Comparative Pharmacology
Head-to-head clinical analysis: FEXINIDAZOLE versus PYRIMETHAMINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FEXINIDAZOLE versus PYRIMETHAMINE.
FEXINIDAZOLE vs PYRIMETHAMINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fexinidazole is a nitroimidazole derivative that enters the parasite and inhibits DNA synthesis by forming reactive metabolites, leading to cell death. It is active against Trypanosoma brucei gambiense.
Pyrimethamine inhibits dihydrofolate reductase (DHFR) in the parasite, blocking the conversion of dihydrofolate to tetrahydrofolate, thereby inhibiting nucleic acid synthesis.
500 mg orally twice daily for 10 days for trichomoniasis; 2 g orally single dose for giardiasis.
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.
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
moderateApproximately 8-12 hours in adults; prolonged in hepatic impairment.
Terminal 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.
Primarily renal (60-70% unchanged), with 20-30% biliary/fecal.
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.
Category C
Category D/X
Antiprotozoal
Antimalarial / Antiprotozoal
Cyclophosphamide + Pyrimethamine
"The metabolism of Pyrimethamine can be decreased when combined with Cyclophosphamide."