Pyrimethamine interactions

Pyrimethamine (Daraprim), an antimalarial has 45 documented interactions across the FDA labels and fact sheets we index: 3 major, 37 moderate, 5 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.

Interactions from the label

Major interactions (3)

  • Folic acid (folate)Vitamin and mineralMajor

    Use of the drug is also contraindicated in patients with documented megaloblastic anemia due to folate deficiency. (Pyrimethamine label, Contraindications)

  • Penicillamine should not be used in patients who are receiving concurrently gold therapy, antimalarial or cytotoxic drugs, oxyphenbutazone or phenylbutazone because these drugs are also associated with similar serious hematologic and renal adverse reactions. (Penicillamine label, Precautions)

  • SulfadiazinesulfonamideMajor

    In infants less than 2 months of age (except as adjunctive therapy with pyrimethamine in the treatment of congenital toxoplasmosis). (Sulfadiazine label, Contraindications)

Moderate interactions (37)

  • Acetazolamidecarbonic anhydrase inhibitorModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Articaine and epinephrinelocal anestheticModerate

    …ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, ifosfamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sulfonamides Antimalarials chloroquine, primaquine Anticonvulsants phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine Monoamine Oxidase… (Articaine and epinephrine label, Drug interactions)

  • Atovaquone and proguanilantimalarialModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Brinzolamidecarbonic anhydrase inhibitorModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Bupivacainelocal anestheticModerate

    • Drugs Associated with Methemoglobinemia : Patients are at increased risk of developing methemoglobinemia when concurrently exposed to nitrates, nitrites, local anesthetics, antineoplastic agents, antibiotics, antimalarials, anticonvulsants, and other drugs. (Bupivacaine label, Drug interactions)

  • Bupivacaine and epinephrinelocal anestheticModerate

    • Drugs Associated with Methemoglobinemia : Patients are at increased risk of developing methemoglobinemia when concurrently exposed to nitrates, nitrites, local anesthetics, antineoplastic agents, antibiotics, antimalarials, anticonvulsants, and other drugs. (Bupivacaine and epinephrine label, Drug interactions)

  • Chloroprocainelocal anestheticModerate

    …procaine, ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, ifosfamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sulfonamides Antimalarials chloroquine, primaquine Anticonvulsants Phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine (Chloroprocaine label, Precautions)

  • ChloroquineantimalarialModerate

    Patients infected with a resistant strain of plasmodia as shown by the fact that normally adequate doses have failed to prevent or cure clinical malaria or parasitemia should be treated with another form of antimalarial therapy. (Chloroquine label, Warnings)

  • DapsoneModerate

    Folic acid antagonists such as pyrimethamine may increase the likelihood of hematologic reactions. (Dapsone label, Drug interactions)

  • DarunavirantiretroviralModerate

    Antimalarial : artemether/lumefantrine ↓ artemether ↓ dihydroartemisinin ↑ lumefantrine ↔ darunavir The combination of PREZISTA/ritonavir and artemether/lumefantrine can be used without dose adjustments. (Darunavir label, Drug interactions)

  • Darunavir and cobicistatantiretroviralModerate

    Antimalarial: artemether/lumefantrine artemether: effect unknown lumefantrine: effect unknown Monitor for a potential decrease of antimalarial efficacy or potential QT prolongation. (Darunavir and cobicistat label, Drug interactions)

  • Dichlorphenamidecarbonic anhydrase inhibitorModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Dorzolamidecarbonic anhydrase inhibitorModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Dorzolamide and timololcarbonic anhydrase inhibitorModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Droperidoldopamine antagonistModerate

    Possible pharmacodynamic interactions can occur between droperidol and potentially arrhythmogenic agents such as class I or III antiarrhythmics, antihistamines that prolong the QT interval, antimalarials, calcium channel blockers, neuroleptics that prolong the QT interval, and antidepressants. (Droperidol label, Drug interactions)

  • EfavirenzantiretroviralModerate

    Antimalarials: Artemether/lumefantrine Atovaquone/ proguanil ↓ artemether * ↓ dihydroartemisinin * ↓ lumefantrine * ↓ atovaquone ↓ proguanil Consider alternatives to artemether/ lumefantrine because of the risk of QT interval prolongation. (Efavirenz label, Drug interactions)

  • Antimalarials: Artemether/lumefantrine ↓ artemether ↓ dihydroartemisinin ↓ lumefantrine Consider alternatives to artemether/lumefantrine because of the risk of QT interval prolongation [see Warnings and Precautions (5.16) ] . (Efavirenz, lamivudine, and tenofovir label, Drug interactions)

  • EtravirineantiretroviralModerate

    Antimalarial : artemether/lumefantrine ↔ etravirine ↓ artemether ↓ dihydroartemisinin ↓ lumefantrine Caution is warranted when co-administering Etravirine and artemether/lumefantrine as it is unknown whether the decrease in exposure of artemether or its active metabolite, dihydroartemisinin, could result in decreased antimalarial efficacy. (Etravirine label, Drug interactions)

  • HydroxychloroquineQT-prolonging drugModerate

    Co-administration of PLAQUENIL with other antimalarials known to lower the seizure threshold (e.g., mefloquine) may increase the risk of seizures. (Hydroxychloroquine label, Drug interactions)

  • Lamivudine and zidovudineantiretroviralModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • LeucovorinModerate

    Folinic acid (leucovorin) should be administered in a dosage of 5 to 15 mg daily (orally, IV, or IM) until normal hematopoiesis is restored. (Pyrimethamine label, Warnings)

  • Lidocaine and epinephrinelocal anestheticModerate

    Drugs Associated with Methemoglobinemia: Patients are at increased risk of developing methemoglobinemia when concurrently exposed to nitrates, nitrites, local anesthetics, antineoplastic agents, antibiotics, antimalarials, anticonvulsants, and other drugs. (Lidocaine and epinephrine label, Drug interactions)

  • Lidocaine and prilocainelocal anestheticModerate

    …prilocaine, procaine, ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, isofamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sufonamides Antimalarials chloroquine, primaquine Anticonvulsants Phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine (Lidocaine and prilocaine label, Drug interactions)

  • LorazepambenzodiazepineModerate

    Mild hepatotoxicity has been reported in some patients when lorazepam and pyrimethamine were administered concomitantly. (Pyrimethamine label, Drug interactions)

  • MefloquineantimalarialModerate

    Other Antimalarial Drugs Concomitant administration of mefloquine and other related antimalarial compounds (e.g., quinine, quinidine and chloroquine) may produce electrocardiographic abnormalities and increase the risk of convulsions (see WARNINGS ). (Mefloquine label, Drug interactions)

  • Mepivacainelocal anestheticModerate

    …procaine, ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, ifosfamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sulfonamides Antimalarials chloroquine, primaquine Anticonvulsants phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine (Mepivacaine label, Drug interactions)

  • Methazolamidecarbonic anhydrase inhibitorModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • MethotrexateimmunosuppressantModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • Prilocaine and epinephrinelocal anestheticModerate

    …ropivacaine, tetracaine Antineoplastic Agents cyclophosphamide, flutamide, hydroxyurea, ifosfamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sulfonamides Antimalarials chloroquine, primaquine Anticonvulsants phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine The administration… (Prilocaine and epinephrine label, Drug interactions)

  • RifapentineantibioticModerate

    …quinidine, tocainide Antibiotics Chloramphenicol, clarithromycin, dapsone, doxycycline; Fluoroquinolones (such as ciprofloxacin) Oral Anticoagulants Warfarin Anticonvulsants Phenytoin Antimalarials Quinine Azole Antifungals Fluconazole, itraconazole, ketoconazole Antipsychotics Haloperidol Barbiturates Phenobarbital Benzodiazepines Diazepam Beta-Blockers Propranolol… (Rifapentine label, Drug interactions)

  • Ropivacainelocal anestheticModerate

    …ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, ifosfamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sulfonamides Antimalarials chloroquine, primaquine Anticonvulsants Phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine NAROPIN should be… (Ropivacaine label, Drug interactions)

  • Silver sulfadiazinesulfonamideModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • SulfasalazinesulfonamideModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • TrimethoprimantibioticModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • ZidovudineantiretroviralModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

  • ZonisamideanticonvulsantModerate

    However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. (Pyrimethamine label, Drug interactions)

Minor mentions (5)

  • AtovaquoneantimalarialMinor

    Drug Interactions: Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics. (Pyrimethamine label, Drug interactions)

  • PrimaquineantimalarialMinor

    Drug Interactions: Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics. (Pyrimethamine label, Drug interactions)

  • QuinidineantiarrhythmicMinor

    Pediatric use In antimalarial trials, quinidine was as safe and effective in pediatric patients as in adults. (Quinidine label, Precautions)

  • QuinineantimalarialMinor

    Drug Interactions: Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics. (Pyrimethamine label, Drug interactions)

  • TafenoquineantimalarialMinor

    Drug Interactions: Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics. (Pyrimethamine label, Drug interactions)

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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.