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Pet Health Library

Medications & Supplements

  • Megestrol acetate is given by mouth in the form of a tablet or liquid and is used in dogs or off label in cats to postpone the heat cycle or to treat false pregnancy. It can also be used off label in male dogs to treat prostatic hypertrophy. It should not be used in pregnant pets or pets with uterine disease, diabetes, or breast tumors.

  • Melatonin is given by mouth or as an implant under the skin and is used to treat sleep and behavior disorders, adrenal disease, and non-allergic hair loss, to suppress the heat cycle, and to improve breeding rates. Give as directed. Side effects are not common but may include sleepiness. Do not use in pets that are allergic to it. If a negative reaction occurs, please call your veterinary office.

  • Meloxicam (brand names Metacam, Meloxidyl, Loxicom, OroCAM) is given by mouth in the form of a liquid, capsule, or tablet to treat pain and inflammation in dogs, cats, and other small mammals. Do not use this medication in pets that are allergic to it, or in pets concurrently using corticosteroids or other NSAIDs. If a negative reaction occurs, call your veterinary office.

  • Methazolamide (brand names Neptazane®, GlaucTabs®, Glaumetax®, MZM) is a carbonic anhydrase inhibitor used off label (extra label) to treat open angle glaucoma in dogs and cats. Do not use in pets that are allergic to it, have significant liver, kidney, or adrenal disease, have electrolyte imbalances, have severe obstructive lung disease, or have closed angle glaucoma.

  • Methimazole (brand names Tapazole®, Felimazole®, Felanorm®) is an antithyroid medication used to treat hyperthyroidism in cats. It is given by mouth or applied topically to the skin. Common side effects include vomiting, anorexia, and tiredness, but more severe side effects are possible. It is contraindicated in pregnant or nursing pets, as well as in cats with autoimmune disease, liver or kidney disease, and/or blood and clotting diseases.

  • Methionine (brand name Methio-Form) is a nutritional supplement used to make urine more acidic in cats and dogs. Urine acidifiers help manage certain types of urolithiasis (urinary stones). Methionine comes in gel, chewable, powder, and tablet forms. Monitor urine pH and seek immediate veterinary care if signs of Heinz-body anemia appear in cats (pale gums, red-brown urine, weakness).

  • Methocarbamol is given by mouth or injection and is used on and off label to treat muscle spasms due to injury, inflammation, or certain toxicities. Give as directed by your veterinarian. The most common side effect includes sleepiness. Do not use methocarbamol in pets that are allergic to it. If a negative reaction occurs, please call your veterinary office.

  • Methylprednisolone is given by mouth or injection and is used on and off label to treat inflammatory, immune-mediated, or hormonal conditions. Common side effects include increased drinking, urination, and appetite, dull/dry haircoat, and/or weight gain. Do not use in pets that are allergic to it, receiving NSAIDs, that are recovering from a recent surgery, or in pets with systemic fungal or viral infections, diabetes, Cushing’s disease, stomach or intestinal ulcers. If a negative reaction occurs, please call your veterinary office.

  • Metoclopramide is given by mouth or injection and is used off-label to treat gastrointestinal motility disorders, nausea, and vomiting in dogs, cats, and other animals. Give as directed. Side effects are uncommon but may include restlessness, hyperactivity, muscle twitches, drowsiness, and increased urination. Do not use in pets with intestinal blockage or bleeding, pseudopregnancy, pheochromocytoma, or a history of seizures or head trauma. If a negative reaction occurs, contact your veterinarian.

  • Metoprolol is a beta-blocker used to treat certain heart rhythm problems and hypertension (high blood pressure) in cats and dogs. It has also been used in the treatment of hypertrophic cardiomyopathy (HCM) in cats. It is used off label (extra label) in veterinary medicine.