Penicillin for dogs is most often prescribed as part of treatment for a bacterial infection. It is commonly prescribed for infections of the urinary tract, lungs, and kidneys. A topical penicillin lotion or ointment may be used to treat various skin infections, and penicillin is also sometimes used in treating leptospirosis, wounds, and dental infections.
When prescribing this antibiotic, veterinarians must consider several different factors before determining the dosage to give to the individual dog. He or she will consider how severe the infection is and consider the dog’s size and age. The veterinarian will also try to determine if the dog has any history of or propensity toward an allergic reaction to drugs in the penicillin family. Penicillin may be given as an injection, as an oral liquid or pill, or as a topical ointment or cream.
Owing to several possible serious side effects, veterinarians are prescribing penicillin for dogs with less frequency than they once did. They are more likely to prescribe a different antibiotic if another treatment is available. Possible side effects of penicillin include yeast infections, vomiting, and diarrhea. Dogs are also prone to allergic reactions that can include eczema, swelling, and itching. Even more serious, this antibiotic can sometimes cause kidney damage, liver damage, and a weakened immune system.
Penicillin for dogs can also lead to type I hypersensitivity. This is a severe allergic reaction that can cause anaphylaxis, and the dog may suddenly develop diarrhea, vomiting, and go into shock. Seizures, coma, and even death can quickly follow.
Veterinarians are more likely to prescribe amoxicillin, which is part of the penicillin family, than penicillin for bacterial infections in dogs. While some of the less serious side effects associated with penicillin are possible with amoxicillin, the more serious side effects are uncommon. Other similar drugs in the penicillin family are penicillin G and ticarcillin.
Both penicillin and amoxicillin work to treat infections by impairing production in the bacteria’s cell wall. Drugs in the penicillin family are not effective in treating dogs with viral or parasite infections, though they may be prescribed in some instances to prevent possible secondary bacterial infections from developing. There are also some bacterial infections against which penicillin drugs will be ineffective because the bacteria have developed resistance to the antibiotic.