Comparative Pharmacology
Head-to-head clinical analysis: COTRIM D S versus DIFICID.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COTRIM D S versus DIFICID.
COTRIM D.S. vs DIFICID
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.
Fidaxomicin is a macrocyclic antibiotic that inhibits bacterial RNA polymerase, leading to RNA synthesis inhibition and cell death. It is bactericidal against Clostridioides difficile and has minimal systemic absorption.
160 mg trimethoprim / 800 mg sulfamethoxazole (one double-strength tablet) orally every 12 hours.
200 mg (tablet) orally twice daily for 10 days.
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.
11.7 hours (terminal half-life in healthy subjects); supports twice-daily dosing.
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%.
Fecal (primarily as unchanged drug, ~44% of dose); renal (~1.6% unchanged, <1% as metabolites); biliary (minor).
Category C
Category C
Antibiotic
Antibiotic