Hyperthyroidism is a condition when the amount of thyroid hormone exceeds the normal limit in the blood circulation. The usual cause of this condition is the enlargement of the thyroid gland(s) or a hormone producing thyroid tumor. In feline, this condition is rare and in approximately 80% of the cats, it is observed that hyperthyroidism involves enlargement of both glands. However, in the other 15% only one is enlarged. Hyperthyroidism causes intense activity in the cats causing them to move around with increased speed and playing a vital role in decrement of their health.

The most commonly used medication for the treatment of hyperthyroidism in cats is known as methimazole, and is also called thiamazole. The trade name for this medication is Tapazole. The former name of the medication used was propylthiouracil.

The main mechanism of this medicine is theinhibition of the production of T4/T3 hormones. Methimazole requires a time period of at least 2 to 4 weeks to affect the thyroid level. This medicine also has a few side effects however they are not very serious in nature. But it is advised that constant monitoring of the patient is done to avoid any deterioration of feline health. The size of the thyroid doesn’t decrease but instead, has a chance of increase

The most recent advancement in compounded methimazole for cats has been the production of transdermal methimazole. In a research conducted on 6 cats, this new medication was applied transdermally. Only one of these cats absorbed it completely. It was observed that transdermal methimazole has a positive effect tod hyperthyroidism in cats. This medication is a success as it makes the administration easier and relieves the cat from oral intake. Transdermal methimazole will show improvement even at low doses and assists in avoiding hepatic first pass effect. The skin is an ideal area to administer the drug and thus the drug transportation in the blood stream becomes easier. Some cats might experience cutaneous reactions however, it is highly uncommon. Similarly, in some cases precipitation is also observed. Thus it is to conclude that transdermal methimazole for cats,is the best choice if they otherwise show to methimazole oral intake.

Following are the advantages of methimazole:

  • This medicine a less expensive than radiotherapy or even surgery.
  • Whenever the cats present negative effects, the medication can be discontinued.
  • Normally there are no severe side effects, especially during the first three months. The chances after these 3 months are relatively less.

Following are the disadvantages of methimazole for cats:

  • The dosing frequency of methimazole is twice a day. This dosage is sometimes difficult to give to the cats because of difficulty is administering of the drug this frequently
  • Side effects occur in about 15% of the cats who are on methimazole.Patients experience signs of lethargy, decrease in appetite and nausea/vomiting. The methimazole is usually discontinued until these issues are resolved.
  • In some felines, issues of facial itching have been observed. The medication is instantly discontinued to avoid decline in health.
  • Some cats also show signs of serious liver failure and in such cases methimazole treatment is ceased.