Comparative Pharmacology
Head-to-head clinical analysis: SEPTRA DS versus SYNERCID.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SEPTRA DS versus SYNERCID.
SEPTRA DS vs SYNERCID
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
SEPTRA DS is a combination of trimethoprim and sulfamethoxazole. Trimethoprim inhibits bacterial dihydrofolate reductase, while sulfamethoxazole inhibits dihydropteroate synthase, sequentially blocking folate synthesis and ultimately DNA synthesis in susceptible bacteria.
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.
One DS tablet (800 mg sulfamethoxazole/160 mg trimethoprim) orally every 12 hours for 10-14 days.
7.5 mg/kg IV every 8 hours, administered as a 60-minute infusion.
None Documented
None Documented
Trimethoprim: 8-10 hours; sulfamethoxazole: 10-12 hours (prolonged in renal impairment, e.g., creatinine clearance <30 mL/min increases half-life to >20 hours).
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.
Renal excretion of unchanged drugs accounts for 50-70% of trimethoprim and 20-30% of sulfamethoxazole; biliary excretion is minor (<10% total).
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