can a cat overdose on methimazole

Methimazole Overdose Information

One-time overdoses may cause the adverse reactions that are listed above. White blood cell changes, liver disease, low platelet levels and other serious side effects can also be seen. If you suspect an overdose, immediately contact your veterinarian or an animal poison control center.

How is methimazole given?

Oral tablets or liquid formulations of methimazole are used to deliver the medication orally. It can also be applied as a transdermal gel to hairless skin, typically on the inside of the ear flap. It may take several days or weeks for this medication to start taking effect, and sometimes those effects are not immediately apparent.

If your pet vomits or acts sick after taking the medication without food, give it with food or a small treat. The oral form can be given with food or on an empty stomach. Particularly for compounded medications, carefully measure the liquid or gel dosages and adhere to all label instructions. This drug does not cure hyperthyroidism; rather, it manages the condition, so it must be taken for life.

Women who are nursing or planning a pregnancy should wear gloves when handling medication, cat litter, or treated pets’ bodily fluids. Anyone applying the transdermal gel should wear gloves during administration.

Other Precautions for Methimazole

  • In cats who already have blood abnormalities, autoimmune diseases, or liver disease, methimazole should be avoided or used with extra caution.
  • To prevent medication-induced hypothyroidism, thyroid hormone levels must be regularly monitored (under-active thyroid)
  • Cats given methimazole may give birth to kittens with low thyroid levels. Your veterinarian may recommend a milk replacement for your kitten.

Are there any potential side effects?

During the first three months of treatment, nausea, anorexia, and fatigue are the most frequent side effects. Other, less frequent adverse effects, like gastrointestinal problems and slight variations in your pet’s blood cell counts, are typically transient and go away over time.

Itching, facial scratches, significant variations in blood cell counts, liver disease, and immune-mediated disorders—diseases in which the body’s immune system targets itself—can happen in a tiny portion of pets. Rarely, myasthenia gravis, a neuromuscular disease, can occur.

In pets with liver or kidney disease, this short-acting medication may last longer than 24 hours.


Can a cat overdose on thyroid medication?

If your pet ingests thyroxine or is given an obvious overdose, contact your veterinarian immediately. Your veterinarian may instruct you to induce vomiting, however, do not induce vomiting unless instructed to.

What are the symptoms of overdose of methimazole?

Signs and Symptoms of Overdose The common symptoms of methimazole overdosage are nausea, vomiting, epigastric discomfort, fever, joint pain, itching, body aches, and swelling. [30] Other symptoms include the following: Agranulocytosis or aplastic anemia can also develop within hours to days.

What is the maximum dosing of methimazole?

For oral dosage form (tablets): For hyperthyroidism: Adults—At first, 15 to 60 milligrams (mg) per day, given in 3 divided doses about every 8 hours. The maintenance dose is 5 to 15 mg per day.

How long can a senior cat live on methimazole?

Treating with methimazole is not a cure. Most cats that are diagnosed with hyperthyroidism and are treated only with medical management will live an average of 3-5 years before dying of either heart failure or kidney failure. But, those 3-5 years can be good quality years.