Detomidine
Encyclopedia
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.
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.
and second degree atrioventricular block
(this is not pathologic
in horses). The horse commonly sweat
s 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.
in horses and other large animals, commonly combined with butorphanol
for increased analgesia and depth of sedation. In conjunction with ketamine
it may also be used for intravenous anaesthesia of short duration.
The drug is normally administered by the intravenous route, and is fastest and most efficient when given intravenously . However, in recalcitrant animals, detomidine may be administered by the intramuscular or sublingual
routes. The dose range advised by the manufacturers is 20-40 mcg/kg intravenous for moderate sedation, but this dose may need to be higher if given intramuscularly.
When given intravenously, Detomidine usually takes effect in 2–5 minutes, and recovery is full within 30-60 minutes, (however, this is highly dependent upon the dosage, environment, and the individual animal; some horses are highly resistant to sedation!)
antibiotics is considered particularly dangerous.
Detomidine is a poor premedication when using Ketamine as an anesthetic in horses.
Anesthetic recoveries in horses that have received Ketamine following a Detomidine premedication are often violent with the horse having multiple failures to stand resulting in trauma to itself. Xylazine is a superior premedication with Ketamine resulting in safer recoveries.
Imidazole
Imidazole is an organic compound with the formula C3H4N2. This aromatic heterocyclic is a diazole and is classified as an alkaloid. Imidazole refers to the parent compound, whereas imidazoles are a class of heterocycles with similar ring structure, but varying substituents...
derivative and α2-adrenergic
Alpha-2 adrenergic receptor
The alpha-2 adrenergic receptor is a G protein-coupled receptor associated with the Gi heterotrimeric G-protein. It consists of three highly homologous subtypes, including α2A-, α2B-, and α2C-adrenergic. Some species other than humans express a fourth α2D-adrenergic receptor as well...
agonist
Agonist
An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...
, used as a large animal sedative
Sedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
, primarily used in horses. It is usually available as the salt detomidine hydrochloride
Hydrochloride
In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base . This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid....
. It is a prescription medication available to veterinarians sold under the trade name Dormosedan.
Currently, Detomidine is only licenced for use in horses.
Properties
Detomidine is a sedative with analgesicAnalgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
properties. α2-adrenergic agonists produce dose-dependent sedative and analgesic effects, mediatated by activation of α2 catecholamine
Catecholamine
Catecholamines are molecules that have a catechol nucleus consisting of benzene with two hydroxyl side groups and a side-chain amine. They include dopamine, as well as the "fight-or-flight" hormones adrenaline and noradrenaline released by the adrenal medulla of the adrenal glands in response to...
receptors, thus inducing a negative feedback
Negative feedback
Negative feedback occurs when the output of a system acts to oppose changes to the input of the system, with the result that the changes are attenuated. If the overall feedback of the system is negative, then the system will tend to be stable.- Overview :...
response, reducing production of excitatory neurotransmitters. Due to inhibition of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
, detomidine also has cardiac and respiratory effects and an antidiuretic
Antidiuretic
An antidiuretic is an agent or drug that, administered to an organism, helps control body water balance by reducing urination, opposing diuresis.-Uses:...
action.
Effects
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 bradycardiaBradycardia
Bradycardia , in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their heart...
and second degree atrioventricular block
Atrioventricular block
An atrioventricular block involves the impairment of the conduction between the atria and ventricles of the heart.The causes of pathological AV block are varied and include ischaemia, infarction, fibrosis or drugs. Certain AV blocks can also be found as normal variants, such as in athletes or...
(this is not pathologic
Pathology (disambiguation)
Pathology and -logia, study of) is a medical field specializing in the categorization of diseases. Pathological is the adjective form of the term.Pathology may also refer to:- In science :...
in horses). The horse commonly sweat
SWEAT
SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004.Each of the 13 half-hour episodes of SWEAT features a different outdoor sport: kayaking, mountain biking, ice hockey, beach volleyball, soccer, windsurfing, rowing, Ultimate, triathlon, wakeboarding, snowboarding, telemark...
s to excess, especially on the flanks and neck. Other side effects reported include pilo erection (hair standing erect), ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
, salivation, slight muscle tremors, and (rarely) penile prolapse.
Uses
Sedation and anaesthetic premedicationPremedication
Premedication refer to a drug treatment given to a patient before a medical procedure. These drugs are typically sedative or analgesic....
in horses and other large animals, commonly combined with butorphanol
Butorphanol
Butorphanol is a morphinan-type synthetic opioid analgesic developed by Bristol-Myers. Brand name Stadol was recently discontinued by the manufacturer. It is now only available in its generic formulations, manufactured by Novex, Mylan, Apotex and Ben Venue Laboratories. Butorphanol is most...
for increased analgesia and depth of sedation. In conjunction with ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...
it may also be used for intravenous anaesthesia of short duration.
The drug is normally administered by the intravenous route, and is fastest and most efficient when given intravenously . However, in recalcitrant animals, detomidine may be administered by the intramuscular or sublingual
Sublingual
Sublingual, literally 'under the tongue', from Latin, refers to the pharmacological route of administration by which drugs diffuse into the blood through tissues under the tongue...
routes. The dose range advised by the manufacturers is 20-40 mcg/kg intravenous for moderate sedation, but this dose may need to be higher if given intramuscularly.
When given intravenously, Detomidine usually takes effect in 2–5 minutes, and recovery is full within 30-60 minutes, (however, this is highly dependent upon the dosage, environment, and the individual animal; some horses are highly resistant to sedation!)
Cautions
As detomidine is an arrhythmogenic agent, extreme care should be exercised in horses with cardiac disease, and in the concurrent administration of other arrhythmogenics. The concurrent use of potentiated sulfonamideSulfonamide (medicine)
Sulfonamide or sulphonamide is the basis of several groups of drugs. The original antibacterial sulfonamides are synthetic antimicrobial agents that contain the sulfonamide group. Some sulfonamides are also devoid of antibacterial activity, e.g., the anticonvulsant sultiame...
antibiotics is considered particularly dangerous.
Detomidine is a poor premedication when using Ketamine as an anesthetic in horses.
Anesthetic recoveries in horses that have received Ketamine following a Detomidine premedication are often violent with the horse having multiple failures to stand resulting in trauma to itself. Xylazine is a superior premedication with Ketamine resulting in safer recoveries.