Felimazole
Felimazole is a brand-name veterinary medication containing methimazole, used to treat hyperthyroidism in cats. It works by reducing the production of thyroid hormones to bring elevated hormone levels back to normal.
Felimazole is an antithyroid medication for cats used to manage overactive thyroid gland.
Key facts at a glance
- RxNorm
- 861969
- Generic
- Felimazole
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Felimazole is indicated for the treatment of hyperthyroidism in cats, a condition where the thyroid gland produces excessive thyroid hormones, leading to symptoms such as weight loss, increased appetite, hyperactivity, and coat deterioration.
The active ingredient methimazole inhibits thyroid peroxidase, an enzyme essential for the synthesis of thyroid hormones (T3 and T4). By blocking this process, it reduces excessive thyroid hormone production.
Felimazole is for veterinary use only in cats. Side effects may include vomiting, lethargy, anorexia, and occasionally more serious effects. Regular monitoring of thyroid levels and blood work is required. Must be used with caution in cats with pre-existing liver or blood disorders.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy