Felimazole Tablets For Cats
Felimazole (methimazole) Coated Tablets are indicated for the treatment of hyperthyroidism in cats.
Felimazole is the first licensed medical treatment
for feline hyperthyroidism - the most commonly diagnosed endocrine disorder in
cats. Felimazole comes in the form of small sugar coated tablets
containing the active ingredient thiamazole (methimazole). Felimazole blocks
the synthesis of T4 and T3 within the thyroid gland. It also reversibly blocks
activity of the enzyme thyroid peroxidase.
The data sheet's normal recommended dose is a 2.5 mg tablet
given twice a day for 3 weeks initially - the dose should not depend on the
weight of the cat. A cat should be re-assessed at 3, 6, 10 and 20 weeks and
thereafter every 3 months. Assessing the response to treatment in this way
enables the veterinarian to monitor for side-effects and unrelated complications
Felimazole can be used for the long-term treatment of the
condition. Felimazole is also highly effective for pre-operative stabilization
if surgery is the chosen option. In this case, a 3 week course of treatment is
recommended. This improves anesthetic safety and allows for the unmasking of
underlying conditions such as renal failure.
With clinical trials showing 90% success, Felimazole is an
effective treatment for feline hyperthyroidism. Treatment is reversible and
side-effects are minimal.
Dosage and Administration:
The starting dose of FELIMAZOLE Coated Tablets is 2.5 mg
administered every 12 hours. Following 3 weeks of treatment, the dose should be
titrated to effect based on individual serum total T4 (TT4) levels and clinical
response. Dose adjustments should be made in 2.5 mg increments. The maximum
total dosage is 20 mg per day divided, not to exceed 10 mg as a single
Hematology, biochemistry, and TT4 should be evaluated prior to initiating
treatment and monitored after 3 weeks and 6 weeks of treatment. Thereafter,
bloodwork should be monitored every 3 months and the dose adjusted as necessary.
Cats receiving doses greater than 10 mg per day should be monitored more
For oral use in cats only.
Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian.
- Do not use in cats with hypersensitivity to methimazole,
carbimazole or the excipient, polyethylene glycol.
- Do not use in cats with primary liver disease or renal failure.
- Do not use in cats with autoimmune disease.
- Do not use in cats with hematological disorders (such as anemia, neutropenia,
lymphopenia, or thrombocytopenia) or coagulopathies.
- Do not use in pregnant or lactating queens. Laboratory studies in rats and
mice have shown evidence of teratogenic and embryotoxic effects of methimazole.
Methimazole has anti-vitamin K activity and may induce bleeding
diathesis without evidence of thrombocytopenia.
Not for use in humans. Keep out of reach of children. For use
in cats only.
Wash hands with soap and water after administration to avoid exposure to
drug. Do not break or crush tablets. Wear protective gloves to prevent direct
contact with litter, feces, urine, or vomit of treated cats, and broken or
moistened tablets. Wash hands after contact with the litter of treated cats.
Methimazole is a human teratogen and crosses the placenta concentrating in
the fetal thyroid gland. There is also a high rate of transfer into breast milk.
Pregnant women or women who may become pregnant, and nursing mothers should wear
gloves when handling tablets, litter or bodily fluids of treated cats.
Methimazole may cause vomiting, gastric distress, headache, fever, arthralgia,
pruritus, and pancytopenia. In the event of accidental ingestion/overdose, seek
medical advice immediately and show the product label to the physician.
Use of FELIMAZOLE Coated Tablets in cats with renal dysfunction
should be carefully evaluated. Reversal of hyperthyroidism may be associated
with decreased glomerular filtration rate and a decline in renal function,
unmasking the presence of underlying renal disease.
Due to potentially serious adverse reactions such as hepatopathy, immune
mediated anemia, thrombocytopenia, and agranulocytosis, cats on methimazole
therapy should be monitored closely for any sign of illness including fever,
lymphadenopathy or signs of anemia. If a cat becomes ill while on FELIMAZOLE
Coated Tablets, the drug should be stopped and appropriate hematological and
biochemical testing should be done.
Anticoagulants may be potentiated by the anti-vitamin K activity of
FELIMAZOLE Coated Tablets. Concurrent use of phenobarbital may reduce the
clinical effectiveness of FELIMAZOLE Coated Tablets. A reduction in dose of
certain drugs (?-adrenergic blocking agents, digitalis glycosides, and
theophylline) may be needed when the patient becomes euthyroid.
Methimazole is known to reduce the hepatic oxidation of benzimidazole
anthelmintics (e.g. fenbendazole), leading to increased plasma concentration of
these anthelmintics when administered concurrently.
FELIMAZOLE Coated Tablets caused delayed maturation of the testes in young
male cats in the 12-week safety study. The safety of FELIMAZOLE Coated
Tablets has not been evaluated in male cats intended for breeding.
The most common adverse reactions included change in food consumption (increase or decrease), lethargy, vomiting, diarrhea/loose stool, skin lesions, and abnormal vocalization.
Store at controlled room temperature 25°C (77°F) with
excursions between 15°-30°C (59°-86°F) permitted.
Keep the container tightly closed in order to protect from moisture.
Available Sizes: Felimazole Coated Tablets are available in 2.5 mg or 5 mg in
bottles containing 100 tablets.
Rx Medication Sold Only To Licensed Veterinarians & Pharmacies. Current License Must Be On File Prior To Shipping.