Medetomidine is most potent á-2 adrenergic selective agonist, produces consistent sedation, anxiolysis and muscle relaxation, which makes it a popular sedative agent in veterinary anaesthesia. It produces dose dependent sedation and analgesia in animals. In veterinary practice it is used for premedication and as an adjunct to general anaesthesia in several species. Similar to other alpha-2 agonists it exerts its effect through the action on alpha-2 adrenergic receptors. The sedative and anxiolytic effects of á-2 agonists are mediated by agonism of supraspinal autoreceptors situated in the pons, whereas analgesic effects are mediated by agonism of heteroreceptors located in the dorsal horn of the spinal cord. Medetomidine through stimulation of central and peripheral adrenoreceptors, significantly affect cardiovascular function. Medetomidine reduces both rate and depth of respiration. Medetomidine generally used along with butorphanol for premedication prior to induction of general anaesthesia. Medetomidine administration reduces both injectable and inhalant anesthetic requirements in several species.

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Adequate sedation and excellent depth of analgesia were recorded in all the four groups after induction to the end of surgical procedure, however, significantly higher sedation score and depth of analgesia were observed in group D and significantly lower was observed in group A in comparison to other groups. Butorphanol with acepromazine, midazolam, or dexmedetomidine provides adequate sedation and analgesia in the dogs, before induction with propofol, so it made handling of the animals proper and safe before induction. Dexmedetomidine produces most profound sedation and analgesia followed by midazolam and acepromazine along with butorphanol.

Background: Nearly all anaesthetic agent decreases renal and hepatic blood flow, so anaesthetic agents should be selected properly in patients particularly with pre-existing renal and hepatic impairment. The present study conducted to evaluate the effect of acepromazine, midazolam and dexmedetomidine as pre-anaesthetic agent followed by induction with propofol and maintenance with isoflurane on kidney and liver function of client-owned female dogs undergoing elective ovariohysterectomy. Methods: Thirty-two clinically healthy female dogs were randomly divided into four groups with ten animals in the groups A and B and six animals in groups C and D for elective ovariohysterectomy. Animals were premedicated with acepromazine-butorphanol in group A, midazolam-butorphanol in group B, dexmedetomidine (I/M)- butorphanol in group C and dexmedetomidine (I/V)- butorphanol in group D. Animals in all four groups were induced (till effect) with propofol and maintained with isoflurane. Result: All the groups showed non-significant marginal decline in BUN and serum creatinine at 5 minutes after pre-medication. Serum AST and ALT were non-significant decreased in groups A and B and non-significant increase in groups C and D during observations. Serum albumin and globulin gradually but non-significantly decrease in group A after premedication to T20 during anesthesia with isoflurane, then gradually increase upto extubation, but values remained lower in comparison to base values.

The objective of the study was to evaluate the effect of ACE, MID, DEX (IM) and DEX (IV) with butorphanol on quality of induction, induction dose of propofol and incidence of apnoea during anaesthesia in client-owned dogs. Animals were randomly divided into four groups. After pre-medication with atropine sulphate, animals were administered with ACE @ 0.05 mg/kg b.wt IV in group A, MID @ 0.5 mg/kg IV b.wt in group B, DEX @ 15 μg/kg IM b.wt in group C and DEX @ 15 μg/kg IV b.wt in group D along with butorphanol @ 0.2 mg/kg b. wt. I/V. All animals were induced with propofol and maintained with isoflurane till the end of closing last skin suture. Adequate sedation and depth of analgesia was observed in the animals of the all four group and this sedation made handling of the animals proper and safe before induction. Significantly lower dose of propofol was needed for induction in the grous C and D as compared to groups A and B. Incidence of temporary apnoea in groups A and B was 10%, whereas in groups C and D was 30%, but they were managed by assisted ventilation and smoothly maintained with isoflurane without complication. It was found that ACE/MID/DEX with butorphanol has dose-sparing effect and provides adequate sedation and analgesia in the canines. Chances of apnoea may be more with DEX pre-medication, but they can be managed by assisted ventilation without any complication.