Medetomidine is a synthetic drug used as both a surgical anesthetic and analgesic often used as the hydrochloride salt medetomidine hydrochloride. It is a crystalline white alpha-two adrenergic agonist that can be administered as an intravenous drug solution with sterile water. It is currently approved for dogs in the United States, and distributed in the United States by Pfizer Animal Health and by Novartis Animal Health in Canada under the product name Domitor. Other alpha-two agonists used in veterinary medicine include xylazine and detomidine, but their use is less common in small animal surgery. The marketed product is a racemic mixture of 2 stereoisomers; dexmedetomidine is the compound with more useful effects, and is now marketed as Dexdomitor.

The free base form of medetomidine is distributed by the Swedish company I-Tech AB under the product name Selektope for use as an antifouling substance in marine paints.

It is often used in combinations with opioids (butorphanol, buprenorphine etc) as premedication (before a general anaesthetic) in healthy cats and dogs. It can be given by intramuscular injection (IM), subcutaneous injection (SC) or intravenous injection (IV). When delivered intravenously, a significantly decreased dose is used. Some authors suggest a sublingual route is also effective. It is not recommended for diabetics, it is contraindicated in patients with cardiac disease. Due to its potent sedative effects it is commonly used in more aggressive animals, where a drug/combination with a lesser effect (i.e. Acetylpromazine + an Opioid, an Opioid + a Benzodiapezine) would not allow the administration of the inductive agent without risk to the veterinarian. As such the use of alpha-two agonists is only recommended in healthy animals.