Pyrimethamine

Note: As of 2015, pyrimethamine is only available in the US through a special pharmacy program[1]

Administration

Adult Dosing

  • 25-200mg PO (weekly or daily, depending on indication), in combination with other antimicrobials

Pediatric Dosing

  • 1-3mg/kg PO

Special Populations

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

Comments

See Also

References

Authors:

Claire