Felimazole vs. Methimazole for Cats: Comparison Guide

The most typical endocrine condition in cats is hyperthyroidism. Without medication, your cat will working experience a vast assortment of signs or symptoms and not truly feel quite perfectly. 

If you discuss with your veterinarian, they will offer you a couple decisions to treat your cat. Methimazole is a fantastic treatment selection, and there are multiple possibilities for offering your cat this treatment. 

Browse this short article to decipher the discrepancies between brand name title tablets regarded as Felimazole vs. methimazole.

Felimazole Vs. Methimazole: A Swift Comparison Tutorial

Felimazole Methimazole
Style of medicine Antithyroid thioamide Antithyroid thioamide
Active component(s) Methimazole Methimazole
Used to Address Hyperthyroidism (cats) Hyperthyroidism
Out there Varieties Coated tablets Tablets, liquid, transdermal gel
Prescription or OTC Prescription Prescription
Dosing Frequency 1-2 instances for every working day 1-2 occasions for each day
When Does It Start out Doing work? Within 2 weeks In 2-4 weeks
Achievable Side Consequences Vomiting, reduced hunger, a lot less energetic Vomiting, reduced urge for food, much less energetic
Protected for Long-Time period Use? Sure Sure
Fda Accepted Yes Of course

While the chart highlights Felimazole and methimazole, there are two other popular names for the medication. Tapazole is a model identify for methimazole in human medication. Thiamazole is one more name for the lively ingredient methimazole.

Essential Differences in Felimazole and Methimazole for Cats

Methimazole and Felimazole are equivalent in that the lively ingredient is the same in equally prescription drugs. Having said that, the inactive elements are the most important difference. Inactive elements are the parts that make the medication helpful but aren’t the therapeutic component itself. 

Felimazole includes numerous components which includes sugar, coloring, and beeswax that kind the outer coating of the tablets.

Methimazole will come in a variety of sorts together with tablets, liquid, and a transdermal gel (for putting on the underside of the ear). The liquid and transdermal gel need to have to be compounded, or created by pharmacies who focus in getting the first main ingredient and transforming it into other types. Felimazole is only offered in tablet variety.

Methimazole tablets only arrive in 5 mg, 10 mg, and 20 mg strengths (unless compounded). Felimazole will come in two dimensions much better suited for cats – 5 mg and 2.5 mg. A lot of cats commence with a dose of 1.25 mg or 2.5 mg. In addition, the Felimazole tablets are scaled-down and have a sugar coating, producing it less difficult to administer to some felines.

Felimazole and methimazole are Food and drug administration approved for treating hyperthyroidism in cats. However, Felimazole’s package has a number of warnings for people today. Dechra, the organization who helps make Felimazole, felt that the warnings were being needed due to the fact if people get the treatment on their fingers and unintentionally consume some of it, the medicine will get into their units. These warnings are not on generic methimazole since it is a medicine formulated for men and women who have to have to get the medication for wellbeing factors. 

Having said that, whether or not you are offering your cat Felimazole or generic methimazole, you should really consider safety measures when handling this medicine. Persons need to wash their fingers with cleaning soap and drinking water following giving their cat the medication, and put on gloves when cleaning urine, feces (poop), vomit, or litter from their cats. Gloves are also advised if a pill will get moist or broken. 

Even with these warnings, a current examine shown that cat mother and father who gave their cats methimazole by mouth did not have traces of the medication in their urine samples following the study period of time [1].

Execs and Drawbacks: Felimazole Vs. Methimazole

Professionals Downsides
Felimazole Will come in scaled-down dimensions that provide much better dosing possibilities for cats.

Incorporates a sugar coating that masks any disagreeable preferences, generating administering tablets simpler.

A lot more high-priced than generic methimazole.
Methimazole Far more price tag productive than Felimazole.

Can be compounded into a liquid or transdermal gel. Transdermal application of methimazole has been confirmed to be powerful when utilized to the inner pores and skin of the ear [2].

Common tablets can be far more challenging to administer to cats.

Methimazole products get started at 5 mg, which could make obtaining the ideal dose much more demanding.

Effectiveness of Felimazole and Methimazole on Feline Hyperthyroidism

Overall, equally Felimazole and methimazole are powerful at treating hyperthyroidism in cats. In excess of 95 p.c of cats will respond very well to the treatment [3], leading to their thyroid stages to normalize and medical indicators of hyperthyroidism to go absent. 

For oral methimazole, about 80 % of cats will have typical thyroid stages in just two months [4]. For transdermal treatment, it will likely take 4 weeks for your cat’s thyroid levels to normalize. 

Comparing Felimazole and Methimazole Facet Effects

Each methimazole and Felimazole can bring about incredibly comparable aspect effects in cats. Gastrointestinal troubles, or aspect consequences involving the stomach or intestines, can happen together with vomiting, diarrhea, and lowered urge for food. Lethargy, or lessened exercise, may perhaps occur also. 

More mature cats additional usually have underlying kidney ailment, and the kidneys can worsen when having methimazole or Felimazole. Significantly less usually, cats can develop liver illness and might even change a yellow color on their skin and eyes. Extreme itching of the facial area or issues with abnormal bleeding could occur as effectively.

If your cat will take this treatment extended-time period, you might observe facet results these kinds of as behaving withdrawn or depressed, body weight decline, change in the fur coat, weak point, agitation, or diarrhea. Most of these facet outcomes are transient, that means they come and go.

The primary variance involving Felimazole and methimazole is if utilizing transdermal methimazole, cat dad and mom might observe redness or other variations in the skin of the ear the place the medication is utilized. Cats that obtain transdermal methimazole are significantly less likely to have gastrointestinal aspect consequences than Felimazole or methimazole offered by mouth.

Charge Comparison of Felimazole Vs. Methimazole

Felimazole is somewhere around twice the charge of methimazole tablets. Regardless, when compared to the charge of other remedies, Felimazole is comparatively inexpensive at $15 to $20 for every month. Methimazole transdermal or compounded liquid formulations can cost much much more, somewhere around $50 for each thirty day period.

Insurance plan might support with masking your cat’s medicine, but most insurance plan firms do not protect pre-current disorders. This indicates that if your cat was identified with hyperthyroidism prior to obtaining insurance coverage, the enterprise may possibly not go over the price of the treatment. The only way to know for confident is to contact the coverage enterprise you are interested in.

The Base Line

In general, both equally Felimazole and generic methimazole are successful for the remedy of hyperthyroidism in cats. Each can also bring about a myriad of facet outcomes. 

The key variation is that methimazole can be manufactured into liquid or transdermal formulations for pet dad and mom who require an choice to tablets. Even though Felimazole is a far more pricey tablet than generic methimazole, it has a smooth sugar coating that stops cats from tasting the bitter treatment and will come in a more compact dimensions that keeps pet mom and dad from obtaining to lower it for dosing. 

As extended as you’re managing hyperthyroidism, you just cannot go completely wrong with possibly of these drugs.


  1. https://pubmed.ncbi.nlm.nih.gov/35471087/ 
  2. https://pubmed.ncbi.nlm.nih.gov/24174499/ 
  3. https://journals.sagepub.com/doi/pdf/10.1177/1098612X16643252  
  4. https://pubmed.ncbi.nlm.nih.gov/26306818/ 

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