Comparative Pharmacology
Head-to-head clinical analysis: NAFCILLIN SODIUM versus UNASYN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NAFCILLIN SODIUM versus UNASYN.
NAFCILLIN SODIUM vs UNASYN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Nafcillin exerts bactericidal activity by inhibiting bacterial cell wall synthesis via binding to penicillin-binding proteins (PBPs), thereby disrupting peptidoglycan cross-linking. It is resistant to staphylococcal beta-lactamases.
Ampicillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs); sulbactam is a beta-lactamase inhibitor that prevents degradation of ampicillin by beta-lactamases.
1-2 g IV every 4 hours; or 1-2 g IM every 4-6 hours.
3 g (ampicillin 2 g + sulbactam 1 g) IV every 6 hours; total daily dose of sulbactam not to exceed 4 g.
None Documented
None Documented
Approximately 0.5 hour (30 minutes) in adults with normal renal function; prolonged to 1-2 hours in neonates or severe renal impairment. Clinically relevant for dosing every 4-6 hours.
Ampicillin: ~1 hour (normal renal function); sulbactam: ~1-1.4 hours (normal renal function); prolonged in renal impairment (ampicillin up to 20 hours, sulbactam up to 10-15 hours in anuria).
Primarily renal (30-40% unchanged) and hepatic/biliary elimination. Approximately 10-15% excreted in bile via feces.
Renal: ampicillin (~75-90% unchanged) and sulbactam (~75-85% unchanged); biliary/fecal: minimal (<5% for each component).
Category A/B
Category C
Penicillin Antibiotic
Penicillin Antibiotic