Comparative Pharmacology
Head-to-head clinical analysis: ATOVAQUONE AND PROGUANIL HYDROCHLORIDE versus PYRIMETHAMINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ATOVAQUONE AND PROGUANIL HYDROCHLORIDE versus PYRIMETHAMINE.
ATOVAQUONE AND PROGUANIL HYDROCHLORIDE vs PYRIMETHAMINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Atovaquone is a mitochondrial electron transport inhibitor that selectively targets the cytochrome bc1 complex, disrupting pyrimidine synthesis in Plasmodium. Proguanil hydrochloride is a prodrug converted to cycloguanil, which inhibits dihydrofolate reductase (DHFR), blocking DNA synthesis. The combination synergistically inhibits plasmodial replication.
Pyrimethamine inhibits dihydrofolate reductase (DHFR) in the parasite, blocking the conversion of dihydrofolate to tetrahydrofolate, thereby inhibiting nucleic acid synthesis.
250 mg atovaquone/100 mg proguanil hydrochloride (1 tablet) orally once daily for prophylaxis; 4 tablets (1000 mg/400 mg) orally once daily for 3 consecutive days for treatment.
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
moderateAtovaquone: terminal half-life 2-3 days (67-83 hours); prolonged to 4-5 days in malaria due to drug accumulation. Proguanil: terminal half-life 12-21 hours; cycloguanil 14-21 hours.
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.
Atovaquone: >94% excreted unchanged in feces via biliary elimination; renal excretion minimal (<1%). Proguanil: ~40-60% excreted renally as unchanged drug and metabolites (primarily cycloguanil and 4-chlorophenylbiguanide).
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 A/B
Category D/X
Antiprotozoal
Antimalarial / Antiprotozoal
Cyclophosphamide + Pyrimethamine
"The metabolism of Pyrimethamine can be decreased when combined with Cyclophosphamide."