Detomidine is an imidazole derivative and α₂-adrenergic agonist, used as a large animal sedative, primarily used in horses. It is usually available as the salt detomidine hydrochloride. It is a prescription medication available to veterinarians sold under the trade name Dormosedan.

Currently, Detomidine is only licenced for use in horses.

Detomidine is a sedative with analgesic properties. α2-adrenergic agonists produce dose-dependent sedative and analgesic effects, mediatated by activation of α2 catecholamine receptors, thus inducing a negative feedback response, reducing production of excitatory neurotransmitters. Due to inhibition of the sympathetic nervous system, detomidine also has cardiac and respiratory effects and an antidiuretic action.

A profound lethargy and characteristic lowering of the head with reduced sensitivity to environmental stimuli (sound, pain, etc.) are seen with detomidine. A short period of reduced coordination is characteristically followed by immobility and a firm stance with front legs spread. Following administration there is an initial increase in blood pressure, followed by bradycardia and second degree atrioventricular block (this is not pathologic in horses). The horse commonly sweats to excess, especially on the flanks and neck. Other side effects reported include pilo erection (hair standing erect), ataxia, salivation, slight muscle tremors, and (rarely) penile prolapse.

Emma Thompson (born 15 April 1959) is a British actress, comedian and screenwriter. She first came to prominence in 1987 in two BBC TV series, Tutti Frutti and Fortunes of War. Her first major film role was in the 1989 romantic comedy The Tall Guy. In 1992, Thompson won multiple acting awards, including an Academy Award and a BAFTA Award for Best Actress, for her performance in the British drama Howards End. The following year Thompson garnered dual Academy Award nominations, as Best Actress for The Remains of the Day and as Best Supporting Actress for In the Name of the Father.

In 1995, Thompson scripted and starred in Sense and Sensibility, a film adaptation of the Jane Austen novel of the same name, which earned her an Academy Award for Best Adapted Screenplay and a BAFTA Award for Best Actress in a Leading Role among other awards. Other notable film and television credits have included the Harry Potter film series, Much Ado About Nothing (1993), Wit (2001), Love Actually (2003), Angels in America (2003), Nanny McPhee (2005), Stranger than Fiction (2006), Last Chance Harvey (2008), An Education (2009) and Nanny McPhee and the Big Bang (2010).