Atipamezole (hydrochloride)

Atipamezole is an antagonist of α_2A-adrenergic receptors (α_2A-ARs; K_i = 1.86 nM).^1,2 It is selective for α_2A-ARs over α_2B- and α₁-ARs (K_is = 1,949.83 and 13,300 nM, respectively), as well as over 40 receptors, ion channels, and transporters (IC₅₀s = 540->10,000 nM). Atipamezole (0.04, 0.08, and 1.2 mg/kg) reverses bradycardia and sedation induced by the α₂-AR agonist medetomidine in dogs.³ It also prevents hypoalgesia induced by the non-steroidal anti-inflammatory drug (NSAID) ketoprofen in sheep.⁴ Atipamezole (0.3 mg/kg) enhances contralateral circling behavior induced by apomorphine or L-DOPA (Item No. 13248) and prolongs the duration of action of L-DOPA in a rat model of Parkinson’s disease.⁵ Formulations containing atipamezole have been used to reverse the sedative and analgesic effects of dexmedetomidine or medetomidine in dogs. Atipamezole is an imidazole that potently antagonizes the α₂-adrenoceptor (K_i = 1.6 nM).^1,2 It shows selectivity over the α₁-adrenoceptor (K_i = 13,300 nM) and is a poor antagonist at a wide variety of other receptors and channels.² Through its effects at the α₂-adrenoceptor, atipamezole reverses the sedative and analgesic effects of α₂-adrenoceptor agonists, alters cognitive functions and sexual behavior, and has neuroprotective effects.² It may also potentiate the effects of dopaminergic drugs used in Parkinson’s disease.^2,5

WARNING This product is not for human or veterinary use.

1. Vacher, B., Funes, P., Chopin, P., et al. Rigid analogues of the α2-adrenergic blocker atipamezole: Small changes, big consequences. J. Med. Chem. 53(19), 6986-6995 (2010).

2. Pertovaara, A., Haapalinna, A., Sirviö, J., et al. Pharmacological properties, central nervous system effects, and potential therapeutic applications of atipamezole, a selective α2-adrenoceptor antagonist. CNS Drug Rev. 11(3), 273-288 (2005).

3. Vainio, O., and Vähä-Vahe, T. Reversal of medetomidine sedation by atipamezole in dogs. J. Vet. Pharmacol. Ther. 13(1), 15-22 (1990).

4. Lizarraga, I., and Chambers, J.P. Involvement of opioidergic and α2-adrenergic mechanisms in the central analgesic effects of non-steroidal anti-inflammatory drugs in sheep. Res. Vet. Sci. 80(2), 194-200 (2006).

5. Haapalinna, A., Leino, T., and Heinonen, E. The α2-adrenoceptor antagonist atipamezole potentiates anti-Parkinsonian effects and can reduce the adverse cardiovascular effects of dopaminergic drugs in rats. Naunyn Schmiedebergs Arch. Pharmacol. 368(5), 342-351 (2003).