Medetomidine

Medetomidine (active form medetomidine hydrochloride) is a synthetic drug used as both a surgical anesthetic and analgesic. 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 by Pfizer Animal Health under the product name Domitor.

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 (SI) or intravenous injection (II). When delivered intravenously, a significantly decreased dose is used. Some authors suggest a sublingual route is also effective.

Following administration, marked peripheral vasoconstriction and bradycardia are noted. Often the dosage of induction agents (i.e. propofol) may be drastically reduced, as may the volumes of anaesthetic gases (i.e. halothane, isoflurane, sevoflurane) used to maintain general anaesthesia.

It is sometimes used in combination with butorphanol and ketamine (given IM) to produce general anaesthesia for short periods in healthy but fractious felines that will not allow an intravenous induction agent to be given.

Medetomidine has also been used in combination with morphine (or methadone), lignocaine and ketamine in constant rate infusion analgesia in canines. It is often used in so called microdoses for this analgesic effect.

It's effects can be reversed using atipamezole (distributed as Antisedan by Pfizer).