Penicillin G Procaine

General

• Type: Natural Penicillin
• Routes of Administration: IM
• Common Trade Names:

Adult Dosing

Anthrax

• Inhalational (Postexposure Prophylaxis)
  • 1,200,000 units IM q12 hours x 60 days (see below)
  • Info: Total treatment duration = 60 days. Do not give IM for over 2 weeks, switching alternative treatment to complete course
• Cutaneous, Nonsevere (Treatment)
  • 600,000-1,200,000 units/day IM

Endocarditis by susceptible Streptococcus viridans

• 1.2 million units IM q6 hours x 2-4 weeks + aminoglycoside

Neurosyphilis

• 2.4 million units/day IM + 500mg probenecid PO QID x 10-14 days
• Info: Penicillin G aqueous I.V. is preferred

Whipple's Disease

• 1.2 million units/day + streptomycin x 10-14 days
• Followed by trimethoprim/sulfamethoxazole or doxycycline x 1 year

Indications by Disease

Disease	Dose	Context
Syphilis	2.4 million units IM daily	Neurosyphilis

Pediatric Dosing

Avoid use in neonates: increased risk of sterile abscesses and procaine reactions

Indications by Disease

Disease	Dose	Context
Diphtheria	300,000 U/day IM (≤10 kg) or 600,000 U/day IM (>10 kg) x14 days
Syphilis	50,000 units/kg IM daily x 10-14 days	Congenital Syphilis alt

General

• 25,000-50,000 units/kg/day divided 1-2 times/day
• First Dose: 25,000-50,000 units/kg x 1
• Max: 4.8 million units/day

Anthrax

• Inhalational (postexposure prophylaxis)
  • 25,000 units/kg IM q12 hours
  • Max: 1,200,000 units q12 hours
  • Info: Total treatment duration = 60 days. Do not give IM for over 2 weeks, switching alternative treatment to complete course

Syphilis (Congenital)

• 50,000 units/kg/day IM daily x 10 days
• If >1 day of therapy is missed, restart entire course of treatment

Special Populations

• Pregnancy Category: B
• Lactation: Use caution
• Renal Dosing
  • Adult
  • Pediatric
• Hepatic Dosing
  • Adult
  • Pediatric

Contraindications

• Allergy to class/drug
• Avoid use in neonates

Adverse Reactions

Serious

• Procaine reactions: Immediate toxic reactions, particularly when a large single dose is administered (4.8 million units); mental disturbances including anxiety, confusion, agitation, depression, weakness, seizures, hallucinations, combativeness, and fear
• Jarisch-Herxheimer reaction with syphilis treatment
• Pseudomembranous colitis

Common

• Rash, urticaria, exfoliative dermatitis
• Serum-sickness like reaction

Pharmacology

• Half-life: 30m
• Metabolism: Hepatic
• Excretion: Urinary
• Mechanism of Action: Bactericidal; Interferes with cell wall mucopeptide synthesis during active multiplication

See Also

• Antibiotics (Main)