Penicillin G (parenteral)

C. diff Risk


Oral Bioavailability


Approximate Cost



5 million units IV once, then 2.5 million units IV q4h until delivery

Renally cleared, requires dosage adjustment with changes in renal function. Consult a pharmacist for renal dosing.

General Information

Common Usage

  • Therapy of Streptococcal and other documented susceptible infections

  • Syphilis

Drug Monitoring

Renal and hepatic function, CBC with differential, hypersensitivity reactions and IV site for phlebitis.

Adverse Effects

Allergy/rash (immediate or delayed), seizures, cytopenias, eosinophilia, interstitial nephritis, abnormal liver enzymes, serum sickness


Antimicrobial class: Penicillin

Average serum half life: Neonates: <6 days: 3.2 to 3.4 hours. 7 to 13 days: 1.2 to 2.2 hours. >14 days: 0.9 to 1.9 hours.
Pediatrics: 0.5-1.2 hours.
Adults normal renal function: 30- 50 minutes

Route of Elimination: Renal (58% to 85% unchanged drug)