Comparative Pharmacology
Head-to-head clinical analysis: COTRIM D S versus SYNERCID.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COTRIM D S versus SYNERCID.
COTRIM D.S. vs SYNERCID
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.
Synercid is a combination of two streptogramin antibiotics, quinupristin and dalfopristin, which bind to the 50S bacterial ribosome and inhibit protein synthesis. Quinupristin binds to the 23S rRNA near the peptidyl transferase center, while dalfopristin binds to a nearby site and enhances quinupristin's binding. The synergistic effect results in irreversible inhibition of bacterial protein synthesis.
160 mg trimethoprim / 800 mg sulfamethoxazole (one double-strength tablet) orally every 12 hours.
7.5 mg/kg IV every 8 hours, administered as a 60-minute infusion.
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.
The terminal elimination half-life is approximately 0.85 hours for dalfopristin and 1.3 hours for quinupristin; however, the active metabolite of quinupristin has a half-life of about 3.5 hours, supporting 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%.
Primarily hepatic metabolism with biliary excretion; approximately 15% of the dalfopristin dose and 32% of the quinupristin dose are excreted unchanged in feces; renal excretion is minor (<5% for both components).
Category C
Category C
Antibiotic
Antibiotic