Comparative Pharmacology
Head-to-head clinical analysis: SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH versus TRIMPEX 200.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH versus TRIMPEX 200.
SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH vs TRIMPEX 200
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.
Trimethoprim inhibits bacterial dihydrofolate reductase, blocking the conversion of dihydrofolic acid to tetrahydrofolic acid, thereby inhibiting bacterial DNA synthesis.
One double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) orally every 12 hours.
200 mg orally once daily, or 100 mg orally twice daily.
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).
Terminal elimination half-life is 8-10 hours in adults with normal renal function; prolonged to 20-30 hours in renal impairment (CrCl <30 mL/min), requiring dose adjustment.
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 excretion of unchanged drug accounts for approximately 60-80% of elimination, with an additional 10-20% as hepatic metabolites excreted in bile and feces.
Category D/X
Category C
Antibiotic
Antibiotic