Comparative Pharmacology
Head-to-head clinical analysis: BICILLIN L A versus POLYCILLIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BICILLIN L A versus POLYCILLIN.
BICILLIN L-A vs POLYCILLIN
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.
Polycillin (ampicillin) is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking, leading to cell lysis.
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.
250-500 mg orally every 6 hours or 500 mg intravenously every 4-6 hours for moderate to severe infections.
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 is 0.5-1 hour in adults with normal renal function; prolonged to 7-10 hours in anuria.
Renal: 60-90% unchanged; biliary/fecal: minor (<10%)
Renal excretion of unchanged drug accounts for 60-80% via glomerular filtration and tubular secretion; 20-40% is hepatically metabolized and eliminated in bile/feces.
Category C
Category C
Penicillin Antibiotic
Penicillin Antibiotic