ATCvet code: QN05 CM90
Pharmacodynamics
The active substance of the veterinary medicinal product is detomidine. Its chemical structure is 4-(2,3-dimethylbenzyl) imidazole hydrochloride. Detomidine is an alpha-2 adrenoceptor agonist with a central effect inhibiting the transmission of noradrenalinmediated nervous impulses. In the animal, the level of consciousness is lowered and the pain threshold is increased. The duration and level of sedation are dose dependent. In the studies conducted with the recommended 40µg/kg dose of the gel, the time to onset of sedation has been approximately 30-40 min and the duration of sedation 2 to 3 hours. With detomidine administration, heart rate is decreased. A transient change in the conductivity of the cardiac muscle may occur, as evidenced by partial atrioventicular and sinoauricular blocks. Respiratory rate is slightly decreased. In some horses, sweating, salivation and slight muscle tremors may be seen. Partial, transient penis prolapse may occur in stallions and geldings. Blood glucose concentration may be temporally increased.
Pharmacokinetics
At a dose of 40 µg/kg of the veterinary medicinal product, the mean Cmax was 4.3 ng/ml and mean tmax was 1.83 hours (range from 1 to 3 hours). Following sublingual administration, clinical signs of sedation were evident at approximately 30 minutes after dosing.
The bioavailability of detomidine administered as the sublingual gel in the horse is about 22%. If the veterinary medicinal product is swallowed the bioavailability is significantly decreased.
Elimination of detomidine occurs by metabolism with a half-life of about 1.25 hours. Metabolites of the drug are eliminated mainly in the urine.