Side Effects of Megace in Cats

Megestrol acetate, or Megace, is a prescription medication intended for humans that is also prescribed to cats under the name Ovaban. The medication is effective in controlling the heat cycles of female cats. The medication is also used to treat some feline skin problems and is effective to a lesser extent in stopping cats from urinating in improper places in the home. While some pet owners do continue to use this substance, considerable side effects are related to the drug when used in some felines.

  1. Uterine Infections

    • Administering Megace to a cat repeatedly for the purposes of regulating a heat cycle is sometimes considered an alternative to spaying. However, repeated use of the medication for this purpose is known to promote future reproductive problems in the animal, according to Petplace.com. Cats that continue to take this drug for extended periods of time may develop infections in the uterus.

    Addison's Symptoms

    • Megace has a significant affect on the adrenal gland in cats, according to Petplace.com. When the adrenal gland has an adverse reaction to the drug, it slows down or stops production of steroid hormones. This reaction leads to a condition known as Addison's disease, or hypoadrenocortism.

      Addison's disease symptoms may include loss of appetite, weight loss, dehydration, vomiting, shaking, low heart rate and general lethargic behavior.

    Diabetes

    • Many factors contribute to diabetes in cats. This common feline disease happens when the pancreas produces inefficient levels of insulin or when the beta cells within the pancreas do not respond properly to the presence of insulin.

      Obesity, pancreatitis and hyperthyroidism are all contributing factors to diabetes in cats, but the administration of hormone medications such as Megace are also linked to the disease, according to MedicineNet.com.

      If your cat develops diabetes, it may require insulin injections every day. The disease will eventually have a negative affect on all the organs in the cat's system and could shorten its lifespan considerably.

    Cancer

    • Mammary cancer is one of the most common cancers in cats. This cat disease is the equivalent to breast cancer in humans, and it typically strikes its victims between the ages of 10 and 12 years, according to the Mar Vista Animal Medical Center website.

      Administration of the drug Megace has been linked to increased frequency of mammary cancer in female cats. Cats develop tumors that start out the size of a small pea and grow until they break though the skin. Ninety percent of these tumors are malignant in cats. The cancer often spreads to the lymph nodes, chest and brain. Often the cat will succumb to the disease when the tumors make breathing impossible. Chemotherapy and surgical removal of tumors are potential treatments.