{"id":"pyrimethamine-pyr","safety":{"commonSideEffects":[{"rate":null,"effect":"Megaloblastic anemia"},{"rate":null,"effect":"Thrombocytopenia"},{"rate":null,"effect":"Leukopenia"},{"rate":null,"effect":"Rash"},{"rate":null,"effect":"Gastrointestinal disturbances"},{"rate":null,"effect":"Folate deficiency"}]},"_chembl":{"chemblId":"CHEMBL36","moleculeType":"Small molecule","molecularWeight":"248.72"},"_dailymed":{"setId":"fdeff3ed-e783-411a-8317-57e8b0e931e0","title":"PYRIMETHAMINE TABLET [NORTHSTAR RX LLC]"},"mechanism":{"_ai_source":"claude-haiku-4.5","explanation":"Pyrimethamine is a competitive inhibitor of dihydrofolate reductase (DHFR), an enzyme essential for converting dihydrofolate to tetrahydrofolate in the one-carbon transfer pathway. By blocking this enzyme, it depletes tetrahydrofolate pools, which are critical cofactors for nucleotide synthesis. This mechanism is particularly effective against parasites and certain bacteria that cannot salvage preformed nucleotides from their host, making them dependent on de novo synthesis.","oneSentence":"Pyrimethamine inhibits dihydrofolate reductase, blocking the synthesis of tetrahydrofolate and thereby preventing DNA synthesis in parasites and certain microorganisms.","_ai_confidence":"high"},"_scrapedAt":"2026-03-28T05:24:03.627Z","_scrapedBy":"cloudflare-swarm","_wikipedia":null,"indications":{"approved":[{"name":"Malaria (treatment and prophylaxis)"},{"name":"Toxoplasmosis"},{"name":"Pneumocystis jirovecii pneumonia (PCP) prophylaxis and treatment"}]},"trialDetails":[{"nctId":"NCT07384624","phase":"PHASE1, PHASE2","title":"Combining Latency Reversing Agents to Address the HIV Reservoir","status":"NOT_YET_RECRUITING","sponsor":"Erasmus Medical Center","startDate":"2026-04","conditions":"HIV (Human Immunodeficiency Virus), HIV -1 Infection","enrollment":30},{"nctId":"NCT02511054","phase":"PHASE1","title":"Sanaria PfSPZ Challenge With Pyrimethamine Chemoprophylaxis (PfSPZ-CVac Approach): Phase 1 Trial to Determine Safety and Protective Efficacy of Sanaria PfSPZ Challenge With Concurrent Pyrimethamine Treatment That Inhibits Development of Asexual B...","status":"COMPLETED","sponsor":"National Institute of Allergy and Infectious Diseases (NIAID)","startDate":"2015-07-21","conditions":"Malaria","enrollment":57},{"nctId":"NCT00452907","phase":"PHASE4","title":"ACT MALI: Treatment of Malaria Based on Combination Therapies","status":"COMPLETED","sponsor":"Sanofi","startDate":"2005-07","conditions":"Malaria","enrollment":780}],"_emaApprovals":[],"_faersSignals":[],"_approvalHistory":[],"publicationCount":141,"rwe":[],"genericFilers":[],"relatedDrugs":[],"labelChanges":[],"biosimilarFilings":[],"pricing":[],"formularyStatus":[],"manufacturing":[],"companionDiagnostics":[],"competitors":[],"timeline":[],"patents":[],"ownershipHistory":[],"trials":[],"biosimilars":[],"latestUpdates":[],"references":[],"tags":[],"ecosystem":[],"genericManufacturerList":[],"offLabel":[],"developmentCodes":[],"aliases":[],"phase":"marketed","status":"active","brandName":"Pyrimethamine (PYR)","genericName":"Pyrimethamine (PYR)","companyName":"Erasmus Medical Center","companyId":"erasmus-medical-center","modality":"Small molecule","firstApprovalDate":"","aiSummary":"Pyrimethamine inhibits dihydrofolate reductase, blocking the synthesis of tetrahydrofolate and thereby preventing DNA synthesis in parasites and certain microorganisms. Used for Malaria (treatment and prophylaxis), Toxoplasmosis, Pneumocystis jirovecii pneumonia (PCP) prophylaxis and treatment.","enrichmentLevel":3,"visitCount":0,"trialStats":{"total":0,"withResults":0},"verificationStatus":"verified","dataCompleteness":{"mechanism":true,"indications":true,"safety":true,"trials":true,"score":4}}