Comparative Pharmacology
Head-to-head clinical analysis: PENICILLIN G POTASSIUM versus PENICILLIN 2.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PENICILLIN G POTASSIUM versus PENICILLIN 2.
PENICILLIN G POTASSIUM vs PENICILLIN-2
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Bactericidal: inhibits transpeptidases (penicillin-binding proteins) involved in bacterial cell wall synthesis, leading to cell lysis.
Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidase activity, and activating autolytic enzymes.
Streptococcal infectionsPneumococcal infectionsMeningococcal infectionsEndocarditis (in combination with gentamicin)SyphilisClostridial infectionsActinomycosisAnthraxRat bite feverListeria infectionsProphylaxis for rheumatic feverOff-label: Lyme disease, pertussis, leptospirosis
Streptococcal infectionsPneumococcal infectionsMeningococcal infectionsSyphilisLyme diseaseAnthraxActinomycosisProphylaxis for rheumatic fever
1-4 million units IV every 4-6 hours; maximum 24 million units/day
250 mg orally every 6 hours or 500 mg orally every 8 hours for mild to moderate infections; intravenous dosing: 1-2 million units every 4-6 hours.
None Documented
None Documented
0.5-1 hour in normal renal function; prolonged to 3-10 hours in anuria/end-stage renal disease.
30-60 minutes; prolonged in renal impairment (up to 10 hours in anuria)
Mainly renally excreted unchanged (60-90%); minimal hepatic metabolism.
Primarily eliminated unchanged by renal tubular secretion; minor hepatic metabolism to penicilloic acid.
Renal (60-90% as unchanged drug via tubular secretion and glomerular filtration); biliary (minor, <10%); fecal (minimal, <5%).
Renal: 60-80% unchanged; biliary/fecal: minor (10-20%)
Approximately 60% bound primarily to serum albumin.
50-65% bound, primarily to albumin
0.3-0.4 L/kg; low distribution consistent with limited tissue penetration and high water solubility.
0.3-0.5 L/kg; low Vd indicates limited tissue penetration
IM: 60-70%; IV: 100%; Oral: not administered due to acid lability.
Oral: 60-70% (decreased with food); IM: 70-85%
GFR 30-60 mL/min: give 75% of usual dose every 4-6 hours; GFR 10-30 mL/min: give 50% of usual dose every 4-6 hours; GFR <10 mL/min: give 25% of usual dose every 4-6 hours or 100% of usual dose every 8-12 hours
For CrCl 10-50 mL/min: administer every 8-12 hours; for CrCl <10 mL/min: administer every 12-18 hours; hemodialysis: give after dialysis.
No adjustment required for Child-Pugh A, B, or C; primarily renally excreted
No specific Child-Pugh based dose adjustment; use with caution in severe hepatic impairment.
Neonates <7 days: 50,000 units/kg IV every 12 hours; Neonates 7-28 days: 75,000 units/kg IV every 8 hours; Children: 100,000-250,000 units/kg/day IV divided every 4-6 hours (maximum 24 million units/day)
For children >1 month: 25-50 mg/kg/day orally divided every 6-8 hours; severe infections: 100-250 mg/kg/day IV divided every 4-6 hours; maximum 12 g/day.
Initiate at lower end of dosing range; monitor renal function and adjust based on creatinine clearance; typical dose: 1-2 million units IV every 4-6 hours
No specific dose adjustment except for renal function; monitor renal function and adjust dose accordingly.
Rapid IV administration may cause life-threatening arrhythmias or cardiac arrest due to potassium toxicity. Use with caution in patients with renal impairment.
No FDA black box warning.
["Hypersensitivity reactions (anaphylaxis, urticaria, serum sickness-like reactions)","Renal impairment: dose adjustment required","Electrolyte disturbances: hyperkalemia, especially with high doses or renal impairment","CNS toxicity: seizures, especially with high doses or renal impairment (due to penicillin)"]
["Hypersensitivity reactions including anaphylaxis","Severe cutaneous adverse reactions (e.g., Stevens-Johnson syndrome)","Clostridioides difficile-associated diarrhea","Renal impairment requiring dose adjustment","Neurologic toxicity with high doses (seizures)"]
["Hypersensitivity to penicillins","History of immediate hypersensitivity to cephalosporins (cross-reactivity risk)"]
["Hypersensitivity to penicillins","History of severe immediate hypersensitivity reaction to beta-lactam antibiotics"]
Data Pending Review
Data Pending Review
No specific food interactions. Avoid alcohol consumption during treatment as it may reduce therapeutic efficacy.
No significant food interactions. Can be taken with or without food.
No teratogenic effects documented in first trimester; safe in all trimesters. Crosses placenta but no fetal harm.
Penicillin is generally considered low risk; no significant teratogenic effects have been consistently reported in first trimester. Animal studies show no fetal harm. Use is considered safe across all trimesters when indicated.
Compatible with breastfeeding; trace amounts in milk, M/P ratio ~0.04. No adverse effects in infants.
Penicillin is excreted into breast milk in low concentrations (M/P ratio approximately 0.2). It is compatible with breastfeeding; no adverse effects on nursing infants reported. Caution in infants with history of penicillin allergy.
Increased plasma volume may lower serum concentrations. Standard dosing effective; no dose adjustment needed for most indications.
Increased renal clearance in pregnancy may reduce serum concentrations; higher doses may be required for severe infections, but standard dosing is generally adequate. No specific dose adjustment is uniformly recommended; monitor clinical response.
Category A/B
Category C
Administer IV only; avoid intra-arterial or intramuscular injection due to risk of necrosis. Contains potassium (1.7 mEq per million units); monitor serum potassium in renal impairment. Perform rapid IV infusion over 15-30 minutes; avoid continuous infusion due to instability in solution. Check for penicillin allergy history before administration; cross-reactivity with cephalosporins is low but possible. Use within 24 hours when reconstituted; discard unused portions due to rapid degradation.
Penicillin-2 (benzathine penicillin G) is indicated for syphilis and group A streptococcal infections. Intramuscular injection only; avoid intravenous administration. Monitor for Jarisch-Herxheimer reaction. Dose adjustment in renal impairment is not typically required due to slow release.
Report any signs of allergic reaction immediately, such as rash, itching, or difficulty breathing.Complete the full course of therapy even if you feel better.Inform your doctor if you have kidney problems or a high potassium level.This medication is given intravenously (into a vein) and must be administered by a healthcare professional.Do not mix this medication with alcoholic beverages.
Complete the full course as prescribed, even if symptoms improve.Report any rash, difficulty breathing, or swelling immediately.Avoid alcohol during treatment to minimize side effects.Do not stop or change the dose without consulting your doctor.Inform all healthcare providers about this therapy.