Warfarin interactions

Warfarin Potentiates anticoagulant response and can result in serious or fatal bleeding. (Amiodarone label, Drug interactions)

If anticoagulation with ELIQUIS is discontinued for a reason other than pathological bleeding or completion of a course of therapy, consider coverage with another anticoagulant [see Dosage and Administration (2.5) , Warnings and Precautions (5.1) , and Clinical Studies (14.1) ] . (Apixaban label, Boxed warning)

WARNING: SERIOUS ADVERSE REACTIONS OR DEATH IN PATIENTS WITH COMPLETE DPD DEFICIENCY and INCREASED RISK OF BLEEDING WITH CONCOMITANT USE OF VITAMIN K ANTAGONISTS Increased risk of serious adverse reactions or death in patients with complete DPD deficiency • Test patients for genetic variants of DPYD prior to initiating XELODA unless immediate treatment is necessary. (Capecitabine label, Boxed warning)

To reduce this risk, consider coverage with another anticoagulant if PRADAXA is discontinued for a reason other than pathological bleeding or completion of a course of therapy ( 2.6 , 2.7 , 2.8 , 5.1 ). (Dabigatran label, Boxed warning)

In the ENGAGE AF-TIMI 48 study, nonvalvular atrial fibrillation patients with CrCL > 95 mL/min had an increased rate of ischemic stroke with SAVAYSA 60 mg once daily compared to patients treated with warfarin. (Edoxaban label, Boxed warning)

Heparin-induced thrombocytopenia (HIT): Initial therapy with warfarin sodium in HIT has resulted in cases of amputation and death. (Warfarin label, Warnings and precautions)

…use of indwelling epidural catheters • concomitant use of other drugs that affect hemostasis, such as non-steroidal anti-inflammatory drugs (NSAIDs), platelet inhibitors, or other anticoagulants • a history of traumatic or repeated epidural or spinal puncture • a history of spinal deformity or spinal surgery • Optimal timing between the administration of fondaparinux… (Fondaparinux label, Boxed warning)

Heparin-induced thrombocytopenia (HIT): Initial therapy with warfarin sodium in HIT has resulted in cases of amputation and death. (Warfarin label, Warnings and precautions)

Anticoagulants and Antiplatelets Ticagrelor Contraindicated during and 2 weeks after TOLSURA treatment. (Itraconazole label, Drug interactions)

Additional risk factors for bleeding include: body weight <60 kg, propensity to bleed, concomitant use of medications that increase the risk of bleeding (e.g . , warfarin, heparin, fibrinolytic therapy, chronic use of nonsteroidal anti-inflammatory drugs [NSAIDs]) [see Warnings and Precautions (5.1) ] . (Prasugrel label, Boxed warning)

…Antipsychotics Haloperidol Decrease plasma concentrations by 70% Lurasidone Prevention or Management : Concomitant use is contraindicated (See CONTRAINDICATIONS ) Decrease exposure Oral Anticoagulants Prevention or Management: Perform prothrombin time daily or as frequently as necessary to establish and maintain the required dose of anticoagulant Warfarin Decrease… (Rifampin label, Drug interactions)

Anticoagulant: rivaroxaban ↑ rivaroxaban Avoid concomitant use of rivaroxaban and ritonavir. (Ritonavir label, Drug interactions)

If anticoagulation with XARELTO is discontinued for a reason other than pathological bleeding or completion of a course of therapy, consider coverage with another anticoagulant [see Dosage and Administration (2.3 , 2.4) , Warnings and Precautions (5.1) , and Clinical Studies (14.1) ] . (Rivaroxaban label, Boxed warning)

St. John's wort can weaken these medicines by speeding up their breakdown, which can mean organ rejection, clots, or loss of effect. (NCCIH, St. John's Wort)

SOLTAMOX is contraindicated in patients who require concomitant warfarin therapy or have a history of deep vein thrombosis or pulmonary embolus if the indication for treatment is either reduction of breast cancer incidence in high-risk patients or risk reduction of invasive breast cancer after treatment of DCIS [see Warnings and Precautions (5.2) and Drug Interactions… (Tamoxifen label, Contraindications)

Vitamin K reduces the anticoagulant effect of warfarin; sudden changes in intake from supplements or diet can throw off INR. (NIH Office of Dietary Supplements, Vitamin K)

Chronic oral acetaminophen use at a dose of 4,000 mg/day has been shown to cause an increase in international normalized ratio (INR) in some patients who have been stabilized on sodium warfarin as an anticoagulant. (Acetaminophen label, Drug interactions)

…fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine,… (Warfarin label, Drug interactions)

Upon initiation or discontinuation of Adalimumab-fkjp in patients being treated with CYP450 substrates with a narrow therapeutic index, monitoring of the effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) is recommended and the individual dose of the drug product may be adjusted as needed. (Adalimumab label, Drug interactions)

Alcohol can raise or lower warfarin's effect and increase bleeding risk; keep intake steady and discuss it with the prescriber. (NIAAA, Harmful Interactions: Mixing Alcohol with Medicines)

…fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone,… (Warfarin label, Drug interactions)

…phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine,… (Warfarin label, Drug interactions)

…propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem,… (Warfarin label, Drug interactions)

…propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem,… (Warfarin label, Drug interactions)

Concomitant use of amoxicillin and oral anticoagulants may increase the prolongation of prothrombin time. (Amoxicillin label, Drug interactions)

Concomitant use Amoxicillin and Clavulanate Potassium Extended Release Tablets and oral anticoagulants may increase the prolongation of prothrombin time. (Amoxicillin and clavulanate label, Drug interactions)

…amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen,… (Warfarin label, Drug interactions)

…lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase… (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

…ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine,… (Warfarin label, Drug interactions)

• Proguanil may potentiate anticoagulant effect of warfarin and other coumarin-based anticoagulants. (Atovaquone and proguanil label, Drug interactions)

• Warfarin: Use with azithromycin may increase coagulation times; monitor prothrombin time. (Azithromycin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

There was no effect of BISOPROLOL FUMARATE on prothrombin time in patients on stable doses of warfarin. (Bisoprolol label, Drug interactions)

There was no effect of bisoprolol fumarate on prothrombin times in patients on stable doses of warfarin. (Bisoprolol and hydrochlorothiazide label, Precautions)

…capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine,… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

However, there has been one report of prolonged prothrombin time when buspirone was added to the regimen of a patient treated with warfarin. (Buspirone label, Drug interactions)

…metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol,… (Warfarin label, Drug interactions)

…metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol,… (Warfarin label, Drug interactions)

Inhibitors of CYP2C9, 1A2, and/or 3A4 have the potential to increase the effect (increase INR) of warfarin by increasing the exposure of warfarin. (Warfarin label, Drug interactions)

…cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin,… (Warfarin label, Drug interactions)

Those at risk include patients with renal or hepatic impairment, or poor nutritional state, as well as patients receiving a protracted course of antimicrobial therapy, and patients previously stabilized on anticoagulant therapy. (Cefixime label, Warnings and precautions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

Those at risk include patients with renal or hepatic impairment, or poor nutritional state, as well as patients receiving a protracted course of antibacterial therapy, and patients receiving anticoagulant therapy. (Cephalexin label, Warnings and precautions)

Drug Interactions Cholestyramine for Oral Suspension USP may delay or reduce the absorption of concomitant oral medication such as phenylbutazone, warfarin, thiazide diuretics (acidic), or propranolol (basic), as well as tetracycline, penicillin G, phenobarbital, thyroid and thyroxine preparations, estrogens and progestins, and digitalis. (Cholestyramine label, Drug interactions)

…montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib,… (Warfarin label, Drug interactions)

…miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine,… (Warfarin label, Drug interactions)

…oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine,… (Warfarin label, Drug interactions)

…Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics… (Warfarin label, Drug interactions)

…phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole,… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

Table 3: Drugs that Can Increase the Risk of Bleeding Drug Class Specific Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin,… (Warfarin label, Drug interactions)

Concomitant use of drugs that increase bleeding risk, antibiotics, antifungals, botanical (herbal) products, and inhibitors and inducers of CYP2C9, 1A2, or 3A4. (Warfarin label, Drug interactions)

Coenzyme Q10 may reduce the effectiveness of warfarin. (NCCIH, Coenzyme Q10)

Patients with a susceptibility to deficiencies of vitamin K (e.g., patients on warfarin, patients with malabsorption syndromes) or other fat-soluble vitamins may be at increased risk. (Colesevelam label, Warnings and precautions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir,… (Warfarin label, Drug interactions)

…↑13% [↓1%, ↑30%] Valsartan (320 mg) 20 mg ↓6% [↓24%, ↑16%] ↑5% [↓15%, ↑29%] Simvastatin (40 mg) 20 mg ↔ ↑19% Digoxin (0.25 mg) 20 mg loading dose then 10 mg once daily for 7 days ↔ ↔ Warfarin (25 mg) 20 mg loading dose then 10 mg once daily for 7 days ↔ ↔ ↔ = no change (geometric mean ratio of test: reference within 0.80 to 1.25); ↓ or ↑ = parameter was lower or… (Dapagliflozin label, Drug interactions)

Standard therapeutic prothrombin time monitoring for warfarin should be continued. (Darifenacin label, Drug interactions)

The risk of GI hemorrhage may be increased when administering Exjade in combination with drugs that have ulcerogenic or hemorrhagic potential, such as nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, oral bisphosphonates, or anticoagulants. (Deferasirox label, Warnings and precautions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

…diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics and Antifungals There have been reports… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

Warfarin Clinical Impact: Increased INR and prothrombin time in patients receiving PPIs and warfarin concomitantly. (Dexlansoprazole label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Dicloxacillin may reduce the anticoagulant response to dicumarol and warfarin. (Dicloxacillin label, Drug interactions)

…amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir,… (Warfarin label, Drug interactions)

Table 3: Drugs that Can Increase the Risk of Bleeding Drug Class Specific Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin,… (Warfarin label, Drug interactions)

…sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole,… (Warfarin label, Drug interactions)

Dosage adjustment of amitriptyline/nortriptyline, propofol, warfarin, and zidovudine may be necessary if used concomitantly with Depakote ER ( 7.2 ) (Divalproex (valproate) label, Drug interactions)

Concomitant medications were grouped as ACE inhibitors, oral anticoagulants, calcium channel blockers, beta blockers, cardiac glycosides, inducers of CYP3A4, substrates and inhibitors of CYP3A4, substrates and inhibitors of P-glycoprotein, nitrates, sulphonylureas, loop diuretics, potassium sparing diuretics, thiazide diuretics, substrates and inhibitors of tubular… (Dofetilide label, Drug interactions)

Patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. (Doxycycline label, Drug interactions)

Highly Protein-Bound Drugs : Potential for displacement of other drugs from plasma proteins; monitor for adverse reactions to concomitant narrow therapeutic index drugs (e.g., warfarin, cyclosporine, or amphotericin B) when initiating or increasing the dosage of dronabinol oral solution. (Dronabinol label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

Monitor drug levels of oral medications with a narrow therapeutic index (e.g., warfarin) when concomitantly administered with TRULICITY. (Dulaglutide label, Drug interactions)

…diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics and Antifungals There have been reports of changes in… (Warfarin label, Drug interactions)

Exercise caution with concomitant use of warfarin. (Dutasteride and tamsulosin label, Warnings and precautions)

Concomitant use of drugs that increase bleeding risk, antibiotics, antifungals, botanical (herbal) products, and inhibitors and inducers of CYP2C9, 1A2, or 3A4. (Warfarin label, Drug interactions)

Effect of TRIKAFTA on Other Drugs CYP2C9 Substrates Ivacaftor may inhibit CYP2C9; therefore, monitoring of the international normalized ratio (INR) during concomitant use of TRIKAFTA with warfarin is recommended. (Elexacaftor, tezacaftor, and ivacaftor label, Drug interactions)

…amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib,… (Warfarin label, Drug interactions)

…Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics… (Warfarin label, Drug interactions)

Other antiretrovirals: See prescribing information for specific antiretroviral drugs Warfarin Clinical Impact: Increased INR and prothrombin time in patients receiving PPIs, including esomeprazole, and warfarin concomitantly. (Esomeprazole label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

A number of drugs, including ethacrynic acid, have been shown to displace warfarin from plasma protein; a reduction in the usual anticoagulant dosage may be required in patients receiving both drugs. (Ethacrynic acid label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

• Warfarin: Postmarketing reports of increased INR sometimes associated with bleeding. (Exenatide label, Drug interactions)

Coumarin Anticoagulants: Obtain INR before VYTORIN initiation and monitor INR during VYTORIN dosage initiation or adjustment. (Ezetimibe and simvastatin label, Drug interactions)

…tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil,… (Warfarin label, Drug interactions)

Increased Bleeding Risk with Coumarin Anticoagulants Exercise caution when co-administering anticoagulants with fenofibrate capsules because of the potentiation of coumarin-type anticoagulant effects in prolonging the prothrombin time/International Normalized Ratio (PT/INR). (Fenofibrate label, Warnings and precautions)

Standard therapeutic monitoring for warfarin should be continued [see Clinical Pharmacology (12.3) ] . (Fesoterodine label, Drug interactions)

Table 2: Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol,… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

…atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole,… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

Table 2: Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol,… (Warfarin label, Drug interactions)

Table 2: Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol,… (Warfarin label, Drug interactions)

In separate single or multiple dose pharmacokinetic interaction studies with chlorthalidone, nifedipine, propranolol, hydrochlorothiazide, cimetidine, metoclopramide, propantheline, digoxin, and warfarin, the bioavailability of fosinoprilat was not altered by coadministration of fosinopril with any one of these drugs. (Fosinopril label, Drug interactions)

Some botanicals may cause bleeding events when taken alone (e.g., garlic and Ginkgo biloba) and may have anticoagulant, antiplatelet, and/or fibrinolytic properties. (Warfarin label, Drug interactions)

The dosage of warfarin should be reduced to maintain the prothrombin time at the desired level to prevent bleeding complications. (Gemfibrozil label, Warnings)

Some botanicals may cause bleeding events when taken alone (e.g., garlic and Ginkgo biloba) and may have anticoagulant, antiplatelet, and/or fibrinolytic properties. (Warfarin label, Drug interactions)

Asian ginseng may reduce the blood-thinning effect of warfarin. (NCCIH, Asian Ginseng)

…steroids and androgens, cyclophosphamide, phenyramidol, guanethidine, fluconazole, sulfinpyrazone, tetracyclines, clarithromycin, disopyramide, quinolones, and those drugs that are highly protein-bound, such as fluoxetine, nonsteroidal anti-inflammatory drugs, salicylates, sulfonamides, chloramphenicol, coumarins, probenecid and monoamine oxidase inhibitors. (Glimepiride label, Drug interactions)

…angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, propoxyphene, salicylates, somatostatin analogs (e.g., octreotide), sulfonamide antibiotics, nonsteroidal anti-inflammatory agents, chloramphenicol, probenecid, coumarins, voriconazole, H2 receptor antagonists, and quinolones. (Glipizide label, Drug interactions)

Intervention Monitor patients for unusual bruising or bleeding, as adjustments in warfarin dosage may be required. (Glucagon label, Drug interactions)

Glucosamine, alone or with chondroitin, may increase the effect of warfarin and raise bleeding risk. (NCCIH, Glucosamine and Chondroitin for Osteoarthritis)

Possible interactions between glyburide and coumarin derivatives have been reported that may either potentiate or weaken the effects of coumarin derivatives. (Glyburide label, Drug interactions)

Griseofulvin decreases the activity of warfarin-type anticoagulants, so that patients receiving these drugs concomitantly may require dosage adjustment of the anticoagulant during and after griseofulvin therapy. (Griseofulvin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

The incidence of bleeding was greater in patients receiving concomitant antithrombotic medications, such as aspirin, clopidogrel, or warfarin. (Icosapent ethyl label, Warnings and precautions)

…cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir,… (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Upon initiation or discontinuation of RENFLEXIS in patients being treated with CYP450 substrates with a narrow therapeutic index, monitoring of the effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) is recommended and the individual dose of the drug product may be adjusted as needed. (Infliximab label, Drug interactions)

…cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin,… (Warfarin label, Drug interactions)

Inhibitors of CYP2C9, 1A2, and/or 3A4 have the potential to increase the effect (increase INR) of warfarin by increasing the exposure of warfarin. (Warfarin label, Drug interactions)

Drug Interactions Post-marketing reports of increased INR (International Normalized Ratio) have been rarely reported when ivermectin was co-administered with warfarin. (Ivermectin label, Drug interactions)

…clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole,… (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Warfarin Clinical Impact: Increased INR and prothrombin time in patients receiving PPIs and warfarin concomitantly. (Lansoprazole label, Drug interactions)

Warfarin: Monitor INR as teriflunomide may decrease INR. (Leflunomide label, Drug interactions)

Drug Interactions Reports of INR increase with the use of warfarin have been observed. (Levocarnitine label, Drug interactions)

Warfarin Effect may be enhanced. (Levofloxacin label, Drug interactions)

Examples: NSAIDs, aspirin, and warfarin Strong CYP3A4 Inhibitors Clinical Impact: Concomitant use of FETZIMA with strong CYP3A4 inhibitors increases levomilnacipran exposure [see Pharmacokinetics ( 12.3 )] . (Levomilnacipran label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

Oral Anticoagulants Levothyroxine increases the response to oral anticoagulant therapy. (Levothyroxine label, Drug interactions)

Oral Anticoagulants Liothyronine sodium increases the response to oral anticoagulant therapy. (Liothyronine label, Drug interactions)

However, another HMG-CoA reductase inhibitor has been found to produce a less than two-second increase in prothrombin time in healthy volunteers receiving low doses of warfarin. (Lovastatin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Drug Interactions Anticoagulants (oral): Due to potential inhibition of vitamin K activity by methimazole, the activity of oral anticoagulants (e.g., warfarin) may be increased; additional monitoring of PT/INR should be considered, especially before surgical procedures. β-adrenergic blocking agents: Hyperthyroidism may cause an increased clearance of beta blockers… (Methimazole label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

Anticoagulants Metolazone, as well as other thiazide-like diuretics, may affect the hypoprothrombinemic response to anticoagulants; dosage adjustments may be necessary. (Metolazone label, Drug interactions)

Table 2: Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol,… (Warfarin label, Drug interactions)

…Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine,… (Warfarin label, Drug interactions)

Patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. (Minocycline label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

Warfarin Clinical Impact The concomitant use of warfarin with REMERON/REMERONSolTab may result in an increase in INR [see Clinical Pharmacology (12.3) ] . (Mirtazapine label, Drug interactions)

…ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase Bleeding Risk Examples of drugs known to increase the risk of bleeding are presented… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

…fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide,… (Warfarin label, Drug interactions)

Therefore, the prothrombin time, International Normalized Ratio (INR), or other suitable anticoagulation tests should be closely monitored if a quinolone is administered concomitantly with warfarin or its derivatives [see Adverse Reactions ( 6 , 6.1 ,), Clinical Pharmacology ( 12.3 ), and Patient Counseling Information ( 17 )]. (Moxifloxacin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Oral neomycin sulfate may enhance the effect of coumarin in anticoagulants by decreasing vitamin K availability. (Neomycin label, Drug interactions)

Caution should be observed when niacin extended-release tablets are administered concomitantly with anticoagulants; platelet counts should be monitored closely in such patients. (Niacin label, Warnings and precautions)

Coumarin Anticoagulants There have been rare reports of increased prothrombin time in patients taking coumarin anticoagulants to whom nifedipine was administered. (Nifedipine label, Drug interactions)

Anticoagulants Nintedanib is a VEGFR inhibitor and may increase the risk of bleeding. (Nintedanib label, Drug interactions)

…amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone,… (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

This may result in a prolonged half-life for some drugs that are also metabolized by this system (e.g., cyclosporine, theophylline/methylxanthines, warfarin) when coadministered with quinolones. (Ofloxacin label, Drug interactions)

Patients taking omega-3-acid ethyl esters capsules and an anticoagulant or other drug affecting coagulation (e.g., anti-platelet agents) should be monitored periodically. (Omega-3-acid ethyl esters label, Drug interactions)

…mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine,… (Warfarin label, Drug interactions)

Drug Interactions and Decreased Vitamin Absorption ORLISTAT may interact with concomitant drugs including cyclosporine, levothyroxine, warfarin, amiodarone, antiepileptic drugs, and antiretroviral drugs [see Drug Interactions (7) ]. (Orlistat label, Warnings and precautions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

Warfarin Clinical Impact: Increased INR and prothrombin time in patients receiving PPIs, including pantoprazole, and warfarin concomitantly. (Pantoprazole label, Drug interactions)

…Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics… (Warfarin label, Drug interactions)

DRUG INTERACTIONS Bleeding has been reported in patients treated with pentoxifylline extended-release tablets with or without concomitant NSAIDs, anticoagulants, or platelet aggregation inhibitors. (Pentoxifylline label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

…etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral… (Warfarin label, Drug interactions)

…oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin,… (Warfarin label, Drug interactions)

Polycythemia vera Vasculitis Diabetes mellitus 5.9 Endogenous Factors Affecting INR The following factors may be responsible for increased INR response: diarrhea, hepatic disorders, poor nutritional state, steatorrhea, or vitamin K deficiency. (Warfarin label, Warnings and precautions)

…ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase Bleeding Risk Examples of drugs known to increase the risk of bleeding are presented in Table 3 . (Warfarin label, Drug interactions)

…ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase Bleeding Risk Examples of drugs known to increase the risk of bleeding are presented in Table 3 . (Warfarin label, Drug interactions)

…fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz,… (Warfarin label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

…ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase Bleeding Risk Examples of drugs known to increase the risk of bleeding are presented in Table 3 . (Warfarin label, Drug interactions)

…carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital,… (Warfarin label, Drug interactions)

…acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam,… (Warfarin label, Drug interactions)

…allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone,… (Warfarin label, Drug interactions)

Drug Interactions Anticoagulants (oral): Due to the potential inhibition of vitamin K activity by propylthiouracil, the activity of oral anticoagulants (e.g., warfarin) may be increased; additional monitoring of PT/INR should be considered, especially before surgical procedures. (Propylthiouracil label, Drug interactions)

The anticoagulant effect of a single dose of warfarin (measured by prothrombin time) was not significantly changed by quinapril coadministration twice-daily. (Quinapril label, Drug interactions)

Use with Warfarin : Monitor for increases in INR and prothrombin time ( 5.2 , 7 ). (Rabeprazole label, Warnings and precautions)

Warfarin : Monitor prothrombin time when starting or stopping EVISTA. (Raloxifene label, Drug interactions)

…fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil,… (Warfarin label, Drug interactions)

Warfarin: Monitor INR and prothrombin time; dose adjustment of warfarin may be needed to maintain target INR range. (Rifaximin label, Drug interactions)

Table 7: CRESTOR Effects on Other Drugs Warfarin Prevention or Management: In patients taking warfarin, obtain an INR before starting CRESTOR and frequently enough after initiation, dosage titration or discontinuation to ensure that no significant alteration in INR occurs. (Rosuvastatin label, Drug interactions)

…ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase Bleeding Risk Examples of drugs known to increase the risk of bleeding are presented in Table 3 . (Warfarin label, Drug interactions)

…Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics… (Warfarin label, Drug interactions)

There are postmarketing reports of clinically evident bleeding and/or increased INR in patients taking concomitant statins and warfarin. (Simvastatin label, Drug interactions)

Frequent monitoring of relevant laboratory parameters (e.g., International Normalized Ratio [INR] in patients taking warfarin, blood glucose levels in diabetic patients) or drug concentrations of concomitant medications such as cytochrome P450 substrates with a narrow therapeutic index (e.g., certain immunosuppressants) is recommended to ensure safe and effective… (Sofosbuvir and velpatasvir label, Drug interactions)

Inhibitors of CYP2C9, 1A2, and/or 3A4 have the potential to increase the effect (increase INR) of warfarin by increasing the exposure of warfarin. (Warfarin label, Drug interactions)

…Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam,… (Warfarin label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

• Exercise caution with concomitant administration of warfarin ( 5.2 , 7.4 , 12.3 ) (Tamsulosin label, Warnings and precautions)

…cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine,… (Warfarin label, Drug interactions)

Warfarin: Monitor INR as teriflunomide may decrease INR. (Teriflunomide label, Drug interactions)

Oral Vitamin K Antagonist Anticoagulants Changes in anticoagulant activity may be seen with androgens; therefore, more frequent monitoring of international normalized ratio (INR) and prothrombin time are recommended in patients taking warfarin, especially at the initiation and termination of androgen therapy. (Testosterone label, Drug interactions)

Because the tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. (Tetracycline label, Drug interactions)

Warfarin : No significant differences were observed in the steady-state pharmacokinetics of R-warfarin or S-warfarin with the addition of tiagabine given as a single dose. (Tiagabine label, Drug interactions)

Closely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. (Warfarin label, Drug interactions)

The following drug interactions were reported for metronidazole, a chemically-related nitroimidazole and may therefore occur with tinidazole: Warfarin and other oral coumarin anticoagulants: Anticoagulant dosage may need adjustment during and up to 8 days after tinidazole therapy ( 7.1 ) (Tinidazole label, Drug interactions)

Monitor patients on oral medications dependent on threshold concentrations for efficacy and those with a narrow therapeutic index (e.g., warfarin) when concomitantly administered with ZEPBOUND. (Tirzepatide label, Drug interactions)

…contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan,… (Warfarin label, Drug interactions)

Upon initiation or discontinuation of TOFIDENCE, in patients being treated with these types of medicinal products, perform therapeutic monitoring of effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) and the individual dose of the medicinal product adjusted as needed. (Tocilizumab label, Drug interactions)

Intervention: Frequently reevaluate the prothrombin time of patients on warfarin for signs of an interaction and adjust the dosage of warfarin as needed. (Tramadol label, Drug interactions)

For patients taking warfarin, carefully monitor coagulation indices when initiating, titrating, or discontinuing RALDESY. (Trazodone label, Warnings and precautions)

The pharmacokinetics of R- and S- warfarin and the international normalized ratio (INR) in healthy subjects given a single 25 mg dose of warfarin were unaffected by continuous subcutaneous infusion of treprostinil at an infusion rate of 10 ng/kg/min. (Treprostinil label, Drug interactions)

More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. (Warfarin label, Drug interactions)

The effect of oral anticoagulants may be decreased when used concurrently with hydrochlorothiazide; dosage adjustments may be necessary. (Triamterene and hydrochlorothiazide label, Drug interactions)

Inhibitors of CYP2C9, 1A2, and/or 3A4 have the potential to increase the effect (increase INR) of warfarin by increasing the exposure of warfarin. (Warfarin label, Drug interactions)

Dosage adjustment of amitriptyline/nortriptyline, propofol, warfarin, and zidovudine may be necessary if used concomitantly with valproic acid oral solution (7.2) (Valproic acid label, Drug interactions)

• Effect of Smoking Cessation on Other Drugs: Pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) may be altered, necessitating dose adjustment. (Varenicline label, Drug interactions)

…naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics and Antifungals There have been reports of changes in INR in patients taking warfarin and antibiotics or antifungals, but clinical pharmacokinetic… (Warfarin label, Drug interactions)

…enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin,… (Warfarin label, Drug interactions)

…Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafaxine, vilazodone 7.4 Antibiotics… (Warfarin label, Drug interactions)

Vitamin E can inhibit platelet aggregation and vitamin K-dependent clotting, increasing bleeding risk with anticoagulant and antiplatelet drugs. (NIH Office of Dietary Supplements, Vitamin E)

…Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine,… (Warfarin label, Drug interactions)

• Increased Risk of Bleeding : Concomitant use of aspirin, nonsteroidal anti-inflammatory drugs, other antiplatelet drugs, warfarin, or other drugs that affect coagulation may increase risk ( 5.3 ). (Vortioxetine label, Warnings and precautions)

…CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine,… (Warfarin label, Drug interactions)

Use with Warfarin: IMURAN may inhibit the anticoagulant effect of warfarin. (Azathioprine label, Drug interactions)

Anticoagulants: Direct Oral Anticoagulants (DOACs) rivaroxaban dabigatran edoxaban ↑ DOAC Refer to the DOAC prescribing information for concomitant administration with moderate CYP3A inhibitors and/or P-gp inhibitors. (Bictegravir, emtricitabine, and tenofovir alafenamide label, Drug interactions)

Chlorpromazine diminishes the effect of oral anticoagulants. (Chlorpromazine label, Precautions)

Some reports suggest cranberry products may increase the effect of warfarin; controlled studies have been mixed. Monitor INR if intake changes. (NCCIH, Cranberry)

Some botanicals and foods can interact with warfarin sodium through CYP450 interactions (e.g., echinacea, grapefruit juice, ginkgo, goldenseal, St. (Warfarin label, Drug interactions)

In Vivo Drug Interaction Studies Based on drug interaction studies in healthy patients, ULORIC does not have clinically significant interactions with colchicine, naproxen, indomethacin, hydrochlorothiazide, warfarin or desipramine [see Clinical Pharmacology (12.3) ]. (Febuxostat label, Drug interactions)

Omega-3 supplements may mildly prolong bleeding time; the combination with anticoagulants such as warfarin warrants monitoring, though clinically significant bleeding has not been consistently shown. (NIH Office of Dietary Supplements, Omega-3 Fatty Acids)

Consequently, interactions with other drugs which are highly protein bound (e.g., anticoagulants ) would not be expected. (Flecainide label, Drug interactions)

Examples: Nonsteroidal anti-inflammatory agents and other highly protein-boind drugs, salicylcates, sulfonamides, chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, beta-adrenergic blocking agents; potentially with ciprofloxacin, micronazole. (Glyburide and metformin label, Drug interactions)

Some botanicals and foods can interact with warfarin sodium through CYP450 interactions (e.g., echinacea, grapefruit juice, ginkgo, goldenseal, St. (Warfarin label, Drug interactions)

Neither racemic warfarin nor isradipine binding to plasma proteins in vitro was altered by the addition of the other drug. (Isradipine label, Drug interactions)

Potential pharmacokinetic interactions of or with levetiracetam were assessed in clinical pharmacokinetic studies (phenytoin, valproate, warfarin, digoxin, oral contraceptive, probenecid) and through pharmacokinetic screening in the placebo-controlled clinical studies in epilepsy patients. (Levetiracetam label, Drug interactions)

Oral Anticoagulants: Interaction studies with warfarin failed to identify any clinically important effect on the serum concentrations of the anticoagulant or on its anticoagulant effect. (Moexipril label, Drug interactions)

In Vitro Interaction The plasma protein binding of nicardipine was not altered when therapeutic concentrations of furosemide, propranolol, dipyridamole, warfarin, quinidine, or naproxen were added to human plasma in vitro. (Nicardipine label, Drug interactions)

Phenothiazines can diminish the effect of oral anticoagulants. (Prochlorperazine label, Precautions)

Subtherapeutic prothrombin times with concomitant warfarin and sucralfate therapy have been reported in spontaneous and published case reports. (Sucralfate label, Drug interactions)

Torsemide may affect the efficacy and safety of sensitive CYP2C9 substrates or of substrates with a narrow therapeutic range, such as warfarin or phenytoin. (Torsemide label, Drug interactions)

The anticoagulant effect of warfarin was not significantly changed by trandolapril. (Trandolapril label, Drug interactions)

Other Drug Interactions No pharmacokinetic interactions were observed between vardenafil and the following drugs: glyburide, warfarin, digoxin, an antacid based on magnesium-aluminum hydroxide, and ranitidine. (Vardenafil label, Drug interactions)

Warfarin In a study conducted in 16 male volunteers, anastrozole did not alter the exposure (as measured by C max and AUC) and anticoagulant activity (as measured by prothrombin time, activated partial thromboplastin time, and thrombin time) of both R- and S-warfarin. (Anastrozole label, Drug interactions)

In addition, no dosage adjustment is necessary for substrates of CYP2D6 (e.g., dextromethorphan, fluoxetine, paroxetine, or venlafaxine), CYP2C9 (e.g., warfarin), CYP2C19 (e.g., omeprazole, warfarin), or CYP3A4 (e.g., dextromethorphan) when coadministered with ABILIFY MAINTENA. (Aripiprazole label, Drug interactions)

Anticoagulants Interaction studies in humans have shown bumetanide to have no effect on warfarin metabolism or on plasma prothrombin activity. (Bumetanide label, Drug interactions)

In vitro data in human plasma indicate that Doxazosin has no effect on protein binding of digoxin, warfarin, phenytoin, or indomethacin. (Doxazosin label, Drug interactions)

Warfarin Concomitant administration of dutasteride capsules 0.5 mg/day for 3 weeks with warfarin does not alter the steady-state pharmacokinetics of the S- or R-warfarin isomers or alter the effect of warfarin on prothrombin time [see Clinical Pharmacology (12.3) ]. (Dutasteride label, Drug interactions)

Compounds that have been tested in man have included antipyrine, digoxin, propranolol, theophylline, and warfarin and no clinically meaningful interactions were found. (Finasteride label, Drug interactions)

Warfarin An interaction study (P017) with warfarin showed no clinically significant effect of letrozole on warfarin pharmacokinetics. (Letrozole label, Drug interactions)

Drug Interactions No clinically significant drug interactions have been found in studies of losartan potassium with hydrochlorothiazide, digoxin, warfarin, cimetidine and phenobarbital. (Losartan label, Drug interactions)

No significant interactions were found between nisoldipine and warfarin or digoxin. (Nisoldipine label, Drug interactions)

Drug Interactions No interactions have been observed between nizatidine and theophylline, chlordiazepoxide, lorazepam, lidocaine, phenytoin, and warfarin. (Nizatidine label, Drug interactions)

Warfarin — Warfarin (20 mg single dose) did not affect olanzapine pharmacokinetics [see Drug Interactions ( 7.2 )] . (Olanzapine label, Drug interactions)

…Clinically Significant Drug Interaction with TAMIFLU No dose adjustments are needed for either oseltamivir or the concomitant drug when coadministering oseltamivir with amoxicillin, acetaminophen, aspirin, cimetidine, antacids (magnesium and aluminum hydroxides and calcium carbonates), rimantadine, amantadine, or warfarin [see Clinical Pharmacology (12.3) ] . (Oseltamivir label, Drug interactions)

Table 5: Sevelamer Drug Interactions Oral drugs for which sevelamer did not alter the pharmacokinetics when administered concomitantly Digoxin Enalapril Iron Metoprolol Warfarin Oral drugs that have demonstrated interaction with sevelamer and are to be dosed separately from sevelamer carbonate Dosing Recommendations Ciprofloxacin Take at least 2 hours before… (Sevelamer label, Drug interactions)

CYP2C9 (e.g. Warfarin) — Tadalafil had no significant effect on exposure (AUC) to S-warfarin or R-warfarin, nor did tadalafil affect changes in prothrombin time induced by warfarin. (Tadalafil label, Drug interactions)

Warfarin: Multiple oral doses of zaleplon (20 mg q24h for 13 days) did not affect the pharmacokinetics of warfarin (R+)- or (S-)-enantiomers or the pharmacodynamics (prothrombin time) following a single 25-mg oral dose of warfarin. (Zaleplon label, Drug interactions)