Comparative Pharmacology
Head-to-head clinical analysis: BICILLIN L A versus POLYCILLIN N.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BICILLIN L A versus POLYCILLIN N.
BICILLIN L-A vs POLYCILLIN-N
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.
Ampicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking, and activating autolytic enzymes. It is bactericidal against susceptible organisms.
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/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)
Terminal elimination half-life: 0.5-1 hour (normal renal function); increases to 7-10 hours in anuria. Prolonged in neonates (2-4 hours).
Renal: 60-90% unchanged; biliary/fecal: minor (<10%)
Renal: 60-80% unchanged via glomerular filtration and tubular secretion. Biliary: ~20% excreted in bile and feces. Small amount metabolized to penicilloic acid.
Category C
Category C
Penicillin Antibiotic
Penicillin Antibiotic