Comparative Pharmacology
Head-to-head clinical analysis: COTRIM D S versus SULFAMETHOXAZOLE AND TRIMETHOPRIM SINGLE STRENGTH.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COTRIM D S versus SULFAMETHOXAZOLE AND TRIMETHOPRIM SINGLE STRENGTH.
COTRIM D.S. vs SULFAMETHOXAZOLE AND TRIMETHOPRIM SINGLE 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 folate synthesis. Trimethoprim inhibits bacterial dihydrofolate reductase, blocking tetrahydrofolate synthesis. Together, they provide sequential blockade of folate metabolism, leading to bactericidal activity.
160 mg trimethoprim / 800 mg sulfamethoxazole (one double-strength tablet) orally every 12 hours.
1 double-strength tablet (800 mg sulfamethoxazole/160 mg trimethoprim) orally every 12 hours for most infections; single-strength tablet (400 mg/80 mg) is used for prophylaxis: 1 tablet orally daily.
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: 10-12 hours (prolonged in renal impairment); Trimethoprim: 8-11 hours (prolonged in hepatic impairment).
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%.
Sulfamethoxazole: primarily renal (70-90% as unchanged drug and acetylated metabolite); Trimethoprim: renal (50-60% unchanged, rest as metabolites); small biliary/fecal elimination (<5% each).
Category C
Category D/X
Antibiotic
Antibiotic