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Pyrimethamine
From WikEM
Note: As of 2015, pyrimethamine is only available in the US through a special pharmacy program[1]
Contents
Administration
- Type: Antiparasitic, indicated for treatment and prophylaxis of Toxoplasmosis and malaria
- Dosage Forms:
- Routes of Administration: Oral
- Common Trade Names:
Adult Dosing
- 25-200mg PO (weekly or daily, depending on indication), in combination with other antimicrobials
Pediatric Dosing
- 1-3mg/kg PO
Special Populations
- Pregnancy Rating: C
- Lactation risk: Infant risk minimal
- Renal dosing:
Contraindications
- Allergy to class/drug
- megaloblastic anemia due to folate deficiency
Adverse Reactions
Serious
- SJS, TEN
- Pancytopenia, leukopenia, thrombocytopenia, megaloblastic anemia
Common
- Rash
Pharmacology
- Half-life: 52-97 hours
- Metabolism: Hepatic
- Excretion:
Mechanism of Action
- Blocks protozoal dihydrofolate reductase, inhibiting nucleic acid synthesis
