Penicillin G

C. diff Risk


Oral Bioavailability


Approximate Cost

$92.22 IM


12-24 million units/day IV in 6 divided doses

Do not use short-acting IV formulation for single dose treatment of syphilis. This requires the long-acting 2.4 mu pen g benzathine formulation. May be single dose or multiple weekly doses depending on stage of syphilis.

ID consultation recommended

General Information

Common Usage

Therapy of Streptococcal and other documented susceptible infections.

Adverse Effects

  • Allergy/rash (immediate or delayed)

  • Seizures

  • Cytopenias

  • Eosinophilia

  • Interstitial nephritis

  • Abnormal liver enzymes

  • Serum sickness

Additional Information

Pen G for IV infusion is not the same as the long acting benzathine IM formualtion. Used for syphilis; double check when ordering or dispensing

IV Administration
Dilute in 100 mL D5W or NS and administer over 30-60 min. (60 min for 4 or 5 mU doses)

EH Prescribing Restrictions

Community IV Formulary (Metro Area)


Antimicrobial class: Penicillin

Pregnancy category: B

Average serum half life: 1 hour

Urine penetration: Therapeutic

Lung penetration: Therapeutic

CSF penetration: Moderate

Biliary penetration: Therapeutic