Evaluation of pentazocine and lysine acetylsalicylate analgesic premedication in intravenous thiobarbiturate anaesthesia in atropinized dogs

In thiopentone intravenous general anaesthesia in atropinized normal dogs, induction time with lysine acetyl salicylate (LAS) or pentazocine analgesic pre-medication was at par. The duration of anaesthesia was more with pentazocine, but recovery was smoother with LAS. Cardio-pulmonary suppression was subdued with pentazocine and minimal with LAS. Only a moderate decrease in rectal temperature signified that the thermo-regulatory mechanisms and metabolic rate were not significantly affected in both treatments. Neuromuscular incoordination was virtually absent with LAS pre-medication. Non-significant increases in serum glutamate-pyruvate transaminse (SGPT) and serum alkaline phosphatase (SAP) attested to absence of hepatic dysfunction. Values of serum total protein and icterus index within the normal range provided the corroborative evidence. Renal function tests further revealed that the glomerular filteration rate (GFR) remained virtually unaffected by the treatments. On the basis of these findings, for short-term surgical intervention either pentazocine or LAS may be used. However, in view of the remarkably smooth recovery, LAS is recommended, especially for ultra short-term procedures in the canine surgical patient.