Comparative Pharmacology
Head-to-head clinical analysis: COTRIM D S versus NITROFURANTOIN MACROCRYSTALLINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COTRIM D S versus NITROFURANTOIN MACROCRYSTALLINE.
COTRIM D.S. vs NITROFURANTOIN MACROCRYSTALLINE
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.
Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates that inhibit multiple bacterial enzymes involved in carbohydrate metabolism, including acetyl-CoA synthetase, and disrupt cell wall synthesis.
160 mg trimethoprim / 800 mg sulfamethoxazole (one double-strength tablet) orally every 12 hours.
100 mg orally twice daily for 5-7 days (uncomplicated UTI); 100 mg orally every 12 hours for 10-14 days (pyelonephritis: not first-line).
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.
Terminal half-life: 20-60 minutes (short, requires q6h dosing for therapeutic efficacy).
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%.
Renal: 30-40% excreted unchanged in urine. Biliary/fecal: minimal; remainder metabolized or eliminated via other routes.
Category C
Category D/X
Antibiotic
Antibiotic