Cat Antibiotics Side Effects

Cat antibiotics often come in handy to treat infections caused by viruses and bacteria. Basically, the antibiotics kill the bacteria and viruses that cause the infections, but will also kill other organisms that are needed for the proper function of the body. The antibiotics used in cats have some side effects.

Secondary Infections

Secondary infections such as yeast infections are very common in felines after an antibiotic treatment. This is due to the fact that the antibiotics kill all the bacteria in the cat’s body, including the good bacteria and this will facilitate the overgrowth of the other cells such as the yeast cells. These secondary infections will be difficult to treat, since a new cure of antibiotics is not recommended.


Some cats may be allergic to certain types of antibiotics. The allergic reactions to antibiotics are not very common, but when they occur, the cat will present the following symptoms:

  • Rashes
  • Itchy skin
  • Swelling
  • Constricted air ways
  • Impossibility to breathe, but only in rare cases, when the cat develops anaphylactic shock

If your pet is presently suffering from allergic reactions to various other substances such as dust mites or pollens and he has experienced anaphylactic shock, you need to get a test prior to administering the antibiotics your vet prescribes. The test will determine if the cat will be able to get the treatment without developing a negative reaction.

Resistance to Antibiotics

If you don’t administer the treatment for the recommended amount of time and discontinue the cure as you notice your pet is better, he may develop resistance to these antibiotics. This means that the next time he will get the same type of antibiotics, the cat will no longer respond to these.

The cat may respond to other types of antibiotics, but it’s not recommended to interrupt the treatment abruptly and without the recommendation of a vet.

Other Side Effects

The antibiotic treatment in cats may also have other side effects such as:

  • Vomiting, but should be only during the first few days of treatment until the body gets used to the drugs
  • Diarrhea
  • Dehydration
  • Lack of appetite
  • Seizures, if the cat has liver damage and the liver may not assimilate the treatment properly
  • Elevated fever, especially during the first days of treatment
  • Kidney damage, but only after several weeks of treatment
  • Damage to the nervous system
  • Growth abnormalities, if the treatment is administered while the cat is not fully developed

Only administer antibiotics that are prescribed by your vet and don’t give your pet human antibiotics. It’s important to read the labels and ask your vet about the possible side effects of the antibiotics your pet gets. If the side effects you notice in your pet are severe, you should notify the vet, but don’t discontinue the treatment without the doctor’s consent.