Alpha 2 Agonists
Alpha 2 agonists like Xylazine are the Non-opioid analgesics, these are used as Sedatives and muscle relaxant.
Other Alpha 2 Agonists are Medetomidine, Detomidine, Dexamedatomidine, Romifidine, Clonidine and Azepoxole.
Xylazine
Xylazine is a Sedative analgesic and sedative hypnotic. It has predictable sedative analgesic and muscle relaxant action.
Eliminates muscular hypertonicity in drugs and cats given lactamine.
Most commonly administered sedative analgesia are improved when Xylazine is combine with Ketamine.
Xylazine can be combined with butorphanol, guaifanesin and benzodiazepine.
Major effect develop in approximately 10-15min. after i/m and within 3-5 min. following i/v administration.
A dose dependent sleep like state is usually maintained for 1-3 hrs. but the duration of analgesia lasts only for about 15-30min.
It causes bradycardia, Arrhythmias, decreases cardiac output and Blood pressure.
Anticholinergics are routinely recommended prior to Xylazine in all animals except horses and large ruminants.
It decreases the respiratory tract.
Drooling of saliva is commonly observed in ruminants.
The decreased gastrophageal sphincter pressure may result in gastric reflex in dogs.
S/C and I/M administration induces vomiting in both dogs and cats during the early onset of sedation.
It prolongs the G.I. transit time. Unfasted cattle develops tympany.
In horses, Xylazine causes minimal effect on small intestine(caecum and colon). The large intestine motor responses are inhibited, relaxation of large intestine coupled with alpha 2 mediated analgesia results in allivation of visceral pain.
Acute abdominal distension is caused by aerophagia or may be due to parasympatholytic action causing G.I. atony with accumulation of gas and hence Xylazine is not suitable for upper G.I. radiography.
It increases urinary output. It causes transient hypoinsuliememic and hyperglycemia in animals.
It has oxytocin like effect and indiscriminate use in pregnant animals is not advised.
It causes mydriasis and decreases intraocular pressure.
Painful procedures should be carried out with in 10-15min. after onset of sedation continued painful manipulations will shorter the period of sedation and faster recovery.
Xylazine can be administered epidurally and will have longer duration of analgesia in cattle.