Influence of buprenorphine , pentazocine and xylazine analgesia on ketamine anaesthesia in dogs

Abstract

The experiments were conducted in three different parts. In the first part of the experiment the ED50 of the three drugs namely buprenorphine, pentazocine and xylazine was determined using the analgesiometer (tail flick method) in rats and tail clip method in mice. The ED50 of buprenorphine in rats and mice was 0.25 + 0.084 mg/kg and 0.9827 + 0.0751 mg/kg intraperitoneally. The ED50 of pentazocine in rats was 32.60 + 0.071 mg/kg and in mice 48.50 + 0.323 mg/kg. The ED50 of xylazine for analgesia in rats and mice was 1.424 +0.229 mg/kg and 7.523 + 0.47 mg/kg respectively. In the second part of the experiment the influence of buprenorphine, pentazocine and xylazine analgesia on ketamine anaesthesia in dogs were studied. Twenty – four animals divided into four groups (A(K), B(X-K), C(B-K) and D(P-K) were administered with ketamine (20 mg/kg), xylazine (2 mg/kg) plus ketamine (15 mg/kg), buprencrphine (0.03 mg/kg) plus ketamine (15 mg/kg) and pentazocine (2 mg/kg) plus ketamine (15 mg/kg) respectively. The sternal recumbency time, clinical signs, duration of anaesthesia, regaining of sternal recumbency time, mean standing time, total recovery time and haemogram were studied. The sternal recumbency time was minimum in xylazine administered group. Untoward reactions like salivation and rigidity of the muscles were observed in groups A(K) and D(P-K). There was significant reduction in rectal temperature in all the groups. The pulse rate was elevated in group A(K) and depressed in group B(X-K), while a transient increase followed by decrease showed in group C(B-K) and D(P-K) . Respiratory depression was observed in groups C(B-K) and D(P-K). Average duration of anaesthesia was maximum in group B(X-K) while all other groups showed almost similar durations of anaesthesia. The time for regaining of sternal recumbency was also maximum in group B(X-K), then the groups A(K), C(B-K) and D(P-K) respectively. Mean standing time was maximum in group B(X-K). The rest of the groups followed the same pattern as above. The total recovery time was maximum in group C(B-K), then group B(X-K), A(K) and D(P-K) respectively. The study of haemogram showed that, the haemoglobin, packed cell volume and erythrocyte counts decreased at 30 min. after drug administration in groups A(K) and B(X-K) while there was no significant variation in group C(B-K) and D(P-K). The group D(P-K) showed a significant reduction in leucocyte count, while there were no variations in other groups observed. In the third part of the experiment the reversal of anaesthesia using the 2 blocker yohimbine was studied. Twenty-four animals divided into four groups (E,F, G and H) were administered with the same drugs as in the second part of the experiment. Along with that yohimbine (0.25 mg/kg in group E, G and H and 2 mg/kg in group F) was administered 15 min. later. The groups E, F, G and H were designated as K-Y, X-K-Y, B-K-Y and P-K-Y respectively. Uptoward effects exhibited after yohimbine administration were salivation, panting and hyperaesthesia during recovery. Rectal temperature, pulse and respiration were increased in all the groups. The duration of anaesthesia, regaining of sternal recumbency time, mean standing time and total recovery time were significantly reduced in group F(X-K-Y), while there was no variation in the above parameters in group E(K-Y). Only the total recovery time significantly reduced in group G(B-K-Y) and prolongation of standing time and total recovery time was observed in group H(P-K-Y). The haematological changes noticed in the second part of the experiment were completely reversed by yohimbine.