ATCvet code: QN05CM90
Pharmacodynamics
The active substance of this 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 noradrenalin-mediated nervous impulses. In the animal, the level of consciousness is lowered and the pain threshold is increased. The duration and level of sedation and analgesia are dose dependent.
With detomidine administration, heart rate is decreased, blood pressure is initially elevated, and then a steady decline to normal is seen. A transient change in the conductivity of the cardiac muscle may occur, as evidenced by partial atrioventricular (AV) and sinoatrial (SA) blocks. Respiratory responses include an initial slowing of respiration within a few seconds to 1 - 2 minutes after administration, increasing to normal within 5 minutes. Especially at high doses, sweating, piloerection, salivation and slight muscle tremors are frequently seen. Partial, transient penis prolapse may occur in stallions and geldings. In cattle, reversible, mild tympany and increased saliva secretion have been observed. Blood sugar concentration is increased in both animal species.
Pharmacokinetics
Detomidine is rapidly absorbed after intramuscular injection, and tmax varies from 15 min to 30 min. Detomidine is also rapidly distributed. Vd varies between 0.75 1/kg and 1.89 1/kg. Protein binding is 75 % to 85 %. Detomidine is oxidated mainly in the liver; a small proportion is methylated in the kidneys. Most metabolites are excreted in the urine. T½ is 1 - 2 hours. Excretion of detomidine in milk in cattle is low. No detectable amounts are present 23 h after administration.