Penicillin G

Penicillin G



General Information


  • IM deep injection into upper outer quadrant of buttock
  • 20 million unit dosage form administered by continuous IV infusion only
  • Intermittent IV infused over 15-30 minutes

Preparation IM

  • 5 million unit vial reconstituted with 8.2mL SWFI or NS (concentration 500,000 units/mL)
  • 3.2mL diluent for concentration 1,000,000 units/mL
  • Final concentration up to 100,000 units/mL for less IM discomfort


  • Same vial dilutions as above for 5 million unit vial, diluted further to 50,000 to 145,000 units/mL before infusion
  • 20 million unit vial reconstituted with 11.5mL SWFI or NS to final concentration 1,000,000 units/mL further diluted in 1-2L of IV solution

Therapy of Streptococcal and other documented susceptible infections.

  • Endocarditis
  • Meningitis
  • Neurosyphilis
  • Tetanus
  • Toxic shock syndrome

Tier 1 Protected Antimicrobial

  • Narrow spectrum, possible transition for discharge, IV to PO
  • Strategy: Total EBM duration set (inpatient and outpatient)

If an order for Penicillin G is ordered for GBS prophylaxis, pharmacy will automatically substitute to ampicillin 2 gm loading dose followed by 1 gm IV Q4H until delivery

Periodically with prolonged use

  • Electrolytes
  • Hepatic enzymes
  • Renal function
  • Cardiac function
  • Hematologic function

Seizure activity in older adults and patients with decreased renal function

  • Allergy/rash (immediate or delayed)
  • Seizures
  • Cytopenias
  • Eosinophilia
  • Interstitial nephritis
  • Abnormal liver enzymes
  • Serum sickness

No major interactions to report

Antimicrobial class: Penicillin

Pregnancy category: B

Average serum half life: 1 hour

  • Neonates: 3.1 hours if <6 days old, 1.4 hours if 14 days or older

Biliary penetration: Therapeutic

CSF penetration: Poor-Moderate, improved with inflamed meninges

Lung penetration: Therapeutic

Urine penetration: Therapeutic

Bicillin, Pfizerpen