Penicillin G Potassium

IV penicillin for serious susceptible bacterial infections in horses and small animals; bactericidal against gram-positive and sensitive anaerobes. Penicillin G potassium — narrow-spectrum penicillinase-sensitive penicillin. Mechanism: binds PBPs → inhibits peptidoglycan cross-linking → disrupts cell wall synthesis (bactericidal). IV administration required; sensitive to beta-lactamases. Active against gram-positive cocci (Streptococcus, Staphylococcus), Clostridia, Fusobacterium, Listeria. Key information Do NOT give procaine penicillin IV — fatal CNS toxicity. IV potassium penicillin G only for IV use. Monitor potassium levels with high-dose IV therapy. Refrigerate.

IV: dilute in 0.9% NaCl or D5W; infuse over 30 min. IM: dilute and inject deep IM. Administer q4–6h for time-dependent killing. Store at room temperature; protect from light. If a dose is missed Administer as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and resume the normal schedule. Never double up doses to make up for a missed one. Complete the full antibiotic course.

Hypersensitivity: urticaria, pruritus, angioedema, anaphylaxis. Electrolyte imbalance (high potassium load with high-dose IV penicillin G potassium — 1.7 mEq K+ per million units). Seizures (very high doses — neurotoxicity). Superinfection. Phlebitis (IV).

For animals Avoid in penicillin-hypersensitive animals. IV K+ load: monitor potassium and cardiac function with high-dose therapy (1.7 mEq K+/million units). Reduce dose or extend interval in renal impairment. Time-dependent killing — maintain dosing intervals. For people handling this medication Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Penicillin injectable — serious anaphylaxis risk if penicillin-allergic. Inform your doctor of any penicillin allergy. Injectable — administered by veterinary staff only. Wash hands thoroughly with soap and water after handling. If accidentally self-injected, seek emergency medical attention immediately.

Contact your veterinarian. Penicillin overdose rarely causes serious toxicity — GI signs are most common. High-dose IV potassium penicillin G overdose can cause fatal hyperkalemia.