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Methimazole Transdermal Gel and Cream

If your pet is showing signs of weight loss despite her increased appetite, as well as increased thirst and urination, then your pet may be suffering from an overactive thyroid problem (hyperthyroidism). Other signs can include vomiting, diarrhea, hyperactivity, and her coat may appear unkempt, matted, or greasy. If you notice these signs, then you should take her to the veterinarian for a thorough evaluation because treatments are available.

If hyperthyroidism is the diagnosis, then methimazole transdermal (lipoderm) gel and/or cream is a common medicine used by veterinarians to treat the condition.

What Is Methimazole Transdermal Gel or Cream?

Methimazole transdermal gel and/or cream are currently the drug of choice for the treatment of hyperthyroidism in cats. It is often used instead of propylthiouracil because it has a lower incidence of side effects. This medication is not commercially available, so it can only be obtained with a veterinarian’s prescription through a veterinary compounding pharmacy.

Why Methimazole Is Prescribed in Veterinary Medicine

Methimazole is a medication that is used in veterinary medicine to treat hyperthyroidism because it reduces the amount of thyroid hormone being produced by the thyroid gland. The medicine that’s used in the topical gel formulation is the same as that in the commercially manufactured tablets. The only difference is the method of administration. Methimazole is very bitter when taken orally, so this formulation is popular in veterinary medicine because it gets applied across the skin, making it easier to dose the pet.

In addition to being used to treat hyperthyroidism in cats and dogs, methimazole lipoderm gel is also used by veterinarians in cases where the pet is undergoing thyroid surgery or receiving radioactive iodine treatment.

Dosage and Administration of Methimazole

Methimazole transdermal gel is applied topically and should be administered to the pet exactly as prescribed by your veterinarian. The transdermal gel is usually best applied on the inside of the pet’s ear.

If you miss a dose, then give the next dose as soon as you remember or, if it is close to the next scheduled dose, wait and resume with the next regularly scheduled dose. Do not administer a double dose to catch up on a missed dose. When administering the gel, it is important to wear rubber surgical gloves as this medication gets absorbed through the skin and enters the bloodstream. After administering the drug, you should wash your hands thoroughly.

Special Precautions for Using Methimazole Transdermal

This medication should only be administered to the pet it is prescribed for. It should be kept well out of reach of children and pets.

Methimazole should be avoided or used with extra caution in pets that have been diagnosed with liver disease, autoimmune diseases, or pre-existing blood abnormalities. All patients that receive this medication should undergo regular thyroid hormone monitoring to reduce the risk of drug-induced hypothyroidism.

Possible Side Effects of Methimazole Transdermal

Whereas the oral formulation of methimazole can produce GI upset, the topical gel does not. This makes the medication easier to bear for most pets. However, some pets can be sensitive to the drug and can cause injury to the face and neck through scratching. In these cases, the medication will usually be stopped.

Less common, but more severe side effects can include serious changes in the pet’s bone marrow or blood count. Liver problems can also arise in some cases. If blood abnormalities develop, then the pet may require a dose reduction.

In very rare instances, a pet being treated with methimazole lipoderm gel can develop myasthenia gravis, a disease that weakens the muscles.

Known Drug Interactions With Methimazole Transdermal

If your pet is taking other medications, vitamins, herbal therapies, or supplements, you should let the veterinarian know about them. This includes the drug dosages and administration schedules, to help avoid any potential risk of interaction with this medication.

Drugs currently known to have interactions with methimazole include bupropion, digoxin, and warfarin.

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