penicillin G potassium, a narrow-spectrum antibiotic for parenteral use. 
INDICATIONS: It is prescribed in the treatment of many gram-positive bacterial infections (generally excluding Staphylococcus), some gram-negative infections (e.g., Neisseria), syphilis, and some anaerobes. CONTRAINDICATIONS: Known hypersensitivity to this drug or to any penicillin prohibits its use. ADVERSE EFFECTS: Among the more serious adverse effects are allergic reactions that vary from minor skin rashes to anaphylaxis. Nausea and diarrhea occur frequently.
