Comparative Pharmacology
Head-to-head clinical analysis: PYRIMETHAMINE versus QUININE SULFATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PYRIMETHAMINE versus QUININE SULFATE.
PYRIMETHAMINE vs QUININE SULFATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Pyrimethamine inhibits dihydrofolate reductase (DHFR) in the parasite, blocking the conversion of dihydrofolate to tetrahydrofolate, thereby inhibiting nucleic acid synthesis.
Quinine sulfate is a blood schizonticide effective against the asexual erythrocytic forms of Plasmodium spp. It interferes with the parasite's ability to digest hemoglobin, leading to accumulation of toxic heme and parasite death. Quinine also has mild analgesic and antipyretic effects, and may depress cardiac conduction and contractility.
For toxoplasmosis: 200 mg orally once, then 50-75 mg orally once daily for 4-6 weeks, plus sulfadiazine and folinic acid. For malaria prophylaxis: 25 mg orally once weekly.
324 mg orally every 8 hours for 7 days (for treatment of chloroquine-resistant falciparum malaria, in combination with other antimalarials).
None Documented
None Documented
Clinical Note
moderatePyrimethamine + Fesoterodine
"The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Pyrimethamine."
Clinical Note
moderatePyrimethamine + Artemether
"The risk or severity of QTc prolongation can be increased when Pyrimethamine is combined with Artemether."
Clinical Note
moderatePyrimethamine + Lumefantrine
"The risk or severity of QTc prolongation can be increased when Pyrimethamine is combined with Lumefantrine."
Clinical Note
moderateTerminal elimination half-life is approximately 96 hours (range 80-123 hours) in adults with normal renal function; prolonged in renal impairment (up to 200 hours). This long half-life supports weekly dosing regimens.
Terminal elimination half-life: 18 hours (range 16-21 hours) in healthy adults; prolonged in renal impairment (up to 25-30 hours) and severe hepatic impairment.
Primarily renal (approximately 30% unchanged and 20-30% as metabolites); additional biliary/fecal elimination (20-30% as metabolites). Total urinary excretion of parent drug and metabolites accounts for 60-80% of dose.
Renal: 20% unchanged; hepatic metabolism (CYP3A4, CYP2C9) accounts for 80% with metabolites (primarily 3-hydroxyquinine) excreted renally and fecally. Biliary excretion is minor (<5%).
Category D/X
Category D/X
Antimalarial / Antiprotozoal
Antimalarial
Cyclophosphamide + Pyrimethamine
"The metabolism of Pyrimethamine can be decreased when combined with Cyclophosphamide."