Comparative Pharmacology
Head-to-head clinical analysis: COTRIM D S versus SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COTRIM D S versus SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH.
COTRIM D.S. vs SULFAMETHOXAZOLE AND TRIMETHOPRIM DOUBLE STRENGTH
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
COTRIM D.S. is a combination of sulfamethoxazole, a competitive inhibitor of dihydropteroate synthase, and trimethoprim, a reversible inhibitor of dihydrofolate reductase. This sequential blockade of folate synthesis leads to bactericidal activity.
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.
160 mg trimethoprim / 800 mg sulfamethoxazole (one double-strength tablet) orally every 12 hours.
One double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) orally every 12 hours.
None Documented
None Documented
Sulfamethoxazole: 9-12 hours (normal renal function). Trimethoprim: 8-11 hours. Both are prolonged in renal impairment (e.g., creatinine clearance <30 mL/min: >24 hours). Clinical context: dosing interval is typically 12 hours; dose adjustment required if CrCl <30 mL/min.
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).
Sulfamethoxazole: ~20% unchanged in urine, remainder as acetylated and glucuronide metabolites. Trimethoprim: ~50-80% unchanged in urine, remainder as oxidative metabolites. Both undergo renal excretion via glomerular filtration and tubular secretion. Total renal elimination: 70-90% of dose combined. Biliary/fecal: <10%.
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%).
Category C
Category D/X
Antibiotic
Antibiotic