A patient receiving pyrimethamine may develop severe folate deficiency.
Uses of pyrimethamine: treatment of toxoplasmosis, malaria, Pneumocystis
Mechanism of action: binds to dihydrofolate reductase
Situations where folate deficiency may develop:
(1) long-term therapy with poor folate intake
(2) overdose
(3) therapy with another folate antagonist
Manifestations of folate deficiency:
(1) megaloblastic anemia
(2) myelosuppression leading to pancytopenia
(3) bleeding related to thrombocytopenia
(4) low serum folate concentration
Blood count recovery occurs in 6-8 days after discontinuation of pyrimethamine and with folinic acid supplementation.
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Specialty: Nutrition, Pharmacology, clinical
