Atipamezole (Antisedan) is a synthetic α2 adrenergic receptor antagonist. It has also been researched in humans as a potential anti-Parkinsonian drug.

The affinity of atipamezole for α2-adrenoceptors and its α2/α1 selectivity ratio are considerably higher than yohimbine. Atipamezole is not selective for subtypes of α2-adrenoceptors. It has negligible affinity for 5-HT1, 5-HT2 and I2 bindings sites[1].

Atipamezole is well tolerated in rodents. The cardiovascular effects of atipamezole (0.01–1 mg/kg, i.v.) are rather modest in anesthetized, normotensive rats. Atipamezole is commonly used by veterinarians to awaken animals from sedation or anesthesia. Atipamezole increases sexual activity in rats and monkeys. In animals with sustained nociception, atipamezole increases pain-related responses by blocking the noradrenergic feedback inhibition of pain. Atipamezole at low doses has beneficial effects on alertness, selective attention, planning, learning, and recall in experimental animals while not necessarily on short-term working memory[1].