Medetomidine (MPV785 free base) is a selective and orally available α2-adrenoceptor agonist, Ki=1.08 nM, with sedative and analgesic effects and vasoconstrictive hypoxic side effects, and is commonly used in small animal anesthesia.

α2-adrenoceptor:1.08 nM (Ki), α1-adrenoceptor:1750 nM (Ki)

Both enantiomers of Medetomidine (dex- and levoMedetomidine) inhibit cytochrome P450-dependent drug-metabolizing activity in rat and human liver microsomes(100 μg/kg ;from 17 to 23 min.; both enantiomers)[1]. In Rainbow trout(i.p. injection;<5 μmol/kg) or water exposure (<50 nM) caused a 2–7 fold increase in hepatic EROD activity[2].

In rat models, Medetomidine exhibits dose-dependent sedative and analgesic effects. High doses (>100 μg/kg) can result in loss of righting reflex and hypothermia[3]. In anesthetized rats, Medetomidine induces transient hypotension and bradycardia. In denervated rats, it shows potent vasopressor activity (PD₅₀ = 1.7 μg/kg) and suppresses sympathetic nerve activity (ID₅₀ = 1.6 μg/kg)[3].