Comparative Pharmacology
Head-to-head clinical analysis: DIFICID versus SYNERCID.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DIFICID versus SYNERCID.
DIFICID vs SYNERCID
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
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.
200 mg (tablet) orally twice daily for 10 days.
7.5 mg/kg IV every 8 hours, administered as a 60-minute infusion.
None Documented
None Documented
11.7 hours (terminal half-life in healthy subjects); supports twice-daily dosing.
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.
Fecal (primarily as unchanged drug, ~44% of dose); renal (~1.6% unchanged, <1% as metabolites); biliary (minor).
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