Comparative Pharmacology
Head-to-head clinical analysis: BICILLIN L A versus NAFCILLIN SODIUM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BICILLIN L A versus NAFCILLIN SODIUM.
BICILLIN L-A vs NAFCILLIN SODIUM
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Penicillin G benzathine is a slow-release formulation that provides prolonged tissue concentrations. It inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation, and activating autolytic enzymes, leading to cell lysis.
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.
1.2 million units intramuscularly as a single dose for treatment of streptococcal pharyngitis; for syphilis, 2.4 million units intramuscularly weekly for 1-3 weeks depending on stage.
1-2 g IV every 4 hours; or 1-2 g IM every 4-6 hours.
None Documented
None Documented
Terminal half-life: 30-60 hours (prolonged due to slow absorption from IM depot; clinically allows single-dose regimen for syphilis)
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.
Renal: 60-90% unchanged; biliary/fecal: minor (<10%)
Primarily renal (30-40% unchanged) and hepatic/biliary elimination. Approximately 10-15% excreted in bile via feces.
Category C
Category A/B
Penicillin Antibiotic
Penicillin Antibiotic