Penicillin G is a natural penicillin and is available in several different salt forms. Natural penicillins remain the drugs of choice for a variety of bacteria, including group A beta-hemolytic streptococci, many gram positive anaerobes, spirochetes, gram negative aerobic cocci, and some gram negative aerobic bacilli. Generally, if a bacteria is susceptible to a natural penicillin, either penicillin G or V is preferred for treating that infection as long as adequate penetration of the drug to the site of the infection occurs and the patient is not hypersensitive to penicillins.
Penicillin is mainly of benefit only for cases where birds are infected with Pasteurella spp. and some gram-positive organisms. Pasteurella spp. are commonly found in the oral cavity of dogs, cats and other canine and feline predators.
Storage/Stability: Penicillin G sodium and potassium should be protected from moisture to prevent hydrolysis of the compounds. Penicillin G potassium tablets and powder for oral solution should be stored at room temperature in tight containers; avoid exposure to excessive heat. After reconstituting, the oral powder for solution should be stored from 2-8°C (refrigerated) and discarded after 14 days. Penicillin G sodium and potassium powder for injection can be stored at room temperature (15-30°C). After reconstituting, the injectable solution is stable for 7 days when kept refrigerated (2-8°C) and for 24 hours at room temperature. Penicillin G procaine should be stored at 2-8°C; avoid freezing. Benzathine penicillin G should be stored at 2-8°C.