Interaction Checker

Tamsulosin interactions

Tamsulosin (Flomax), an alpha blocker has 82 documented interactions across the FDA labels and fact sheets we index: 43 major, 25 moderate, 14 minor, and 0 where a label reports no significant interaction. Each entry below quotes the sentence behind it. This drug page is a starting point, not a verdict for your situation.

Major interactions (43)

  • Acetazolamidecarbonic anhydrase inhibitorMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

  • Alfuzosinalpha blockerMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • AmiodaroneantiarrhythmicMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • AprepitantCYP3A4 inhibitorMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Carvedilolbeta blockerMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • CenobamateanticonvulsantMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • CimetidineH2 blockerMajor

    Tamsulosin hydrochloride capsules should be used with caution in combination with cimetidine, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg) [see Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.3 )] Tamsulosin hydrochloride capsules should not be used in combination with other alpha adrenergic blocking agents [see Drug Interactions ( 7.2 )… (Tamsulosin label, Warnings and precautions)

  • Clarithromycinmacrolide antibioticMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • CyclosporineimmunosuppressantMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Diltiazemcalcium channel blockerMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Dorzolamidecarbonic anhydrase inhibitorMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

  • Dorzolamide and timololcarbonic anhydrase inhibitorMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

  • Doxazosinalpha blockerMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • DronedaroneantiarrhythmicMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Dutasteride and tamsulosin5-alpha reductase inhibitorMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • Erythromycinmacrolide antibioticMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • EverolimusimmunosuppressantMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Fluconazoleazole antifungalMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • IloperidoneantipsychoticMajor

    Avoid coadministration of FANAPT with alpha-adrenergic blocking agents and adjust medications that affect blood pressure as needed [see Warnings and Precautions (5.7) ] . (Iloperidone label, Drug interactions)

  • ImatinibCYP3A4 inhibitorMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • IsoniazidantibioticMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Itraconazoleazole antifungalMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • IvacaftorCYP3A4 inhibitorMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Ketoconazoleazole antifungalMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Labetalolbeta blockerMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • Mirabegronbeta-adrenergic agonistMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Nirmatrelvir and ritonavirantiviralMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • PalbociclibCYP3A4 inhibitorMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • PerampanelanticonvulsantMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Posaconazoleazole antifungalMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Prazosinalpha blockerMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • RanolazineQT-prolonging drugMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • RitonavirantiretroviralMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Silver sulfadiazinesulfonamideMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

  • Sulfamethoxazole and trimethoprimsulfonamideMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

  • SulfasalazinesulfonamideMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

  • Suvorexantsedative-hypnoticMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • TadalafilPDE5 inhibitorMajor

    CIALIS is not recommended in combination with alpha-blockers for the treatment of BPH because efficacy of the combination has not been adequately studied and because of the risk of blood pressure lowering. (Tadalafil label, Warnings and precautions)

  • Terazosinalpha blockerMajor

    • Should not be used in combination with other alpha adrenergic blocking agents ( 5.2 , 7.2 , 12.3 ) (Tamsulosin label, Warnings and precautions)

  • Ticagrelorantiplatelet agentMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Verapamilcalcium channel blockerMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • Voriconazoleazole antifungalMajor

    • Should not be used in combination with strong inhibitors of CYP3A4. (Tamsulosin label, Warnings and precautions)

  • ZonisamideanticonvulsantMajor

    If a patient reports a serious or life-threatening sulfa allergy, caution is warranted when administering tamsulosin hydrochloride capsules. (Tamsulosin label, Warnings and precautions)

Moderate interactions (25)

  • Allopurinolxanthine oxidase inhibitorModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • Atenololbeta blockerModerate

    Nifedipine, Atenolol, Enalapril Dosage adjustments are not necessary when tamsulosin hydrochloride capsules are administered concomitantly with nifedipine, atenolol, or enalapril [see clinical pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • AvanafilPDE5 inhibitorModerate

    Caution is advised when alpha adrenergic blocking agents including tamsulosin hydrochloride are coadministered with PDE5 inhibitors. (Tamsulosin label, Warnings and precautions)

  • BupropionantidepressantModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • Butalbital, acetaminophen, and caffeinebarbiturateModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • ClobazambenzodiazepineModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • DarifenacinanticholinergicModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • Digoxindigitalis glycosideModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • DiphenhydramineantihistamineModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • DuloxetineSNRIModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • EnalaprilACE inhibitorModerate

    Nifedipine, Atenolol, Enalapril Dosage adjustments are not necessary when tamsulosin hydrochloride capsules are administered concomitantly with nifedipine, atenolol, or enalapril [see clinical pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • Febuxostatxanthine oxidase inhibitorModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • FluoxetineSSRIModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • Furosemideloop diureticModerate

    While furosemide produced an 11% to 12% reduction in tamsulosin hydrochloride C max and AUC, these changes are expected to be clinically insignificant and do not require adjustment of the tamsulosin hydrochloride capsules dosage [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • Naltrexone and bupropionopioid antagonistModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • Nifedipinedihydropyridine calcium channel blockerModerate

    Nifedipine, Atenolol, Enalapril Dosage adjustments are not necessary when tamsulosin hydrochloride capsules are administered concomitantly with nifedipine, atenolol, or enalapril [see clinical pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • ParoxetineSSRIModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • PentoxifyllinemethylxanthineModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • PropafenoneantiarrhythmicModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • Propranololbeta blockerModerate

    Alpha Blockers: Co-administration of beta-blockers with alpha-blocker (e.g., prazosin) has been associated with prolongation of first dose hypotension and syncope. (Propranolol label, Drug interactions)

  • SildenafilPDE5 inhibitorModerate

    Caution is advised when alpha adrenergic blocking agents including tamsulosin hydrochloride are coadministered with PDE5 inhibitors. (Tamsulosin label, Warnings and precautions)

  • TerbinafineantifungalModerate

    Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors. (Tamsulosin label, Warnings and precautions)

  • TheophyllinemethylxanthineModerate

    Digoxin and Theophylline Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology ( 12.3 )] . (Tamsulosin label, Drug interactions)

  • VardenafilPDE5 inhibitorModerate

    Caution is advised when alpha adrenergic blocking agents including tamsulosin hydrochloride are coadministered with PDE5 inhibitors. (Tamsulosin label, Warnings and precautions)

  • WarfarinanticoagulantModerate

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

Minor mentions (14)

  • Dutasteride5-alpha reductase inhibitorMinor

    Coadministration of dutasteride and tamsulosin resulted in similar changes to serum PSA as dutasteride monotherapy. (Dutasteride label, Warnings and precautions)

  • EpinephrinesympathomimeticMinor

    • Drugs that counter the pressor effects of epinephrine include alpha blockers, vasodilators such as nitrates, diuretics, antihypertensives, and ergot alkaloids. (Epinephrine label, Drug interactions)

  • Esmololbeta blockerMinor

    Use in Patients with Pheochromocytoma If BREVIBLOC injection is used in the setting of pheochromocytoma, give it in combination with an alpha-blocker, and only after the alpha-blocker has been initiated. (Esmolol label, Warnings and precautions)

  • HydralazinevasodilatorMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • Isosorbide dinitratenitrateMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • Isosorbide dinitrate and hydralazinenitrateMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • Isosorbide mononitratenitrateMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • Metoprololbeta blockerMinor

    Pheochromocytoma: Initiate therapy with an alpha blocker. (Metoprolol label, Warnings and precautions)

  • Midodrinealpha-adrenergic agonistMinor

    Alpha-adrenergic blocking agents, such as prazosin, terazosin, and doxazosin, can antagonize the effects of midodrine hydrochloride tablets. (Midodrine label, Drug interactions)

  • MinoxidilvasodilatorMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • NitroglycerinnitrateMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • RiociguatvasodilatorMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • Treprostinilprostaglandin analogMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

  • VericiguatvasodilatorMinor

    Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. (Tamsulosin label, Warnings and precautions)

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Not medical advice. Severity reflects the label's wording, not your circumstances. A "major" flag can be routine under supervision and a "minor" one can matter at high doses. Ask a pharmacist.