Comparative Pharmacology
Head-to-head clinical analysis: SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH versus TRIMPEX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH versus TRIMPEX.
SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH vs TRIMPEX
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sulfamethoxazole inhibits bacterial dihydropteroate synthase, blocking folic acid synthesis. Trimethoprim inhibits bacterial dihydrofolate reductase, blocking reduction of dihydrofolate to tetrahydrofolate. Sequential blockade produces bactericidal effect.
Inhibits dihydrofolate reductase, blocking the conversion of dihydrofolic acid to tetrahydrofolic acid, thereby inhibiting bacterial thymidine synthesis and DNA replication.
One double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) orally every 12 hours.
5 mg/kg orally every 6 hours for acute infections; 5 mg/kg orally every 12 hours for chronic urinary tract infections.
None Documented
None Documented
Sulfamethoxazole: 9-11 hours; trimethoprim: 8-11 hours. In severe renal impairment (CrCl <15 mL/min), half-life prolongs significantly (up to 30 hours for trimethoprim).
8-11 hours; prolonged in renal impairment (creatinine clearance <10 mL/min: 20-40 hours)
Both sulfamethoxazole and trimethoprim are primarily excreted via the kidneys. Sulfamethoxazole: ~30% as unchanged drug, ~50% as N4-acetyl metabolite; trimethoprim: ~80% as unchanged drug. Fecal elimination is minimal (<5%).
Renal: 40-70% as unchanged drug; biliary/fecal: minimal (10-15% as metabolites)
Category D/X
Category C
Antibiotic
Antibiotic