Traditionally, medical treatment of feline hyperthyroidism has involved daily use of the azole drugs, methimazole or its pro-drug, carbimazole. Many cats require twice daily treatment with these drugs. A novel controlled-release formulation of carbimazole (Vidalta) has been developed by Intervet. These researchers evaluated the efficacy and safety of this new carbimazole formulation via a multi-center study of 44 client-owned cats with hyperthyroidism. Treatment was started at 15 mg/cat once daily, and dose was adjusted as required. Cats were followed for 53 weeks. The median dose over the study period was 10-15 mg/cat once daily. Clinical signs improved in almost all cats within 3 weeks after treatment was started. An increase in blood urea nitrogen (BUN) was noted in 25% of the cats, eosinophilia was noted in 20%, and lymphopenia in 16%. The researchers conclude that once daily administration of controlled-release carbimazole is effective with acceptable tolerance during short and long term treatment of feline hyperthyroidism (Frenais et al, 2009).
1. Frenais, R., et al. (2009) Clinical efficacy and safety of a once-daily formulation of carbimazole in cats with hyperthyroidism. J Small Anim Pract, 50(10): p. 510-5.