Effi ciency of Pentazocine for Post-operative Analgesia: A Comparative Prospective Study

Background: Pentazocine a relatively new, potent, opioid analgesic used for post-operative analgesia and appears to be longer lasting and has minimal side effects. Materials and Methodology: Randomized comparative prospective study of 75 patients of the American Society of Anesthesiologist Physical Status I and II, aged between 25 and 45 years, of sexes and requiring general anesthesia particularly for upper abdominal surgery, received pentazocine by different routes. After surgery, when patients had Aldrete recovery score around 9-10 patients received pentazocine 300 mcg by various routes of administration as follow: Epidural, intramuscular, intravenous slow bolus over 10 min, continuous infusion over 12 h and sublingual tablets. The patients were studied for 48 h postoperatively. Observation was made half an hourly for 2 h and then hourly. Data collected, tables formulated as per meaningful duration of action observed and as per need of simplicity for analysis. Respiration, pulse rates and blood pressure was monitored. Assessment of pain was carried out with numeric rating scale. Results: Meaningful duration of analgesia by different routes were as follows; epidural: 30-35 h in 53.33% of group population, intramuscular: 6-8 h in 86.67% of group population, intravenous bolus: 5-6 h in 73.33% of group population, intravenous infusion: 16-20 h in 60% of group population, and sublingual: 5-6 h in 66.66% of group population. Side effects observed due to pentazocine considering whole population as study sample were urinary retention in three patients (4%), nausea in fi ve patients (6.67 %), vomiting in two patients (2.66%). No cardiorespiratory depression was observed in any of the patient and route of administration technique. Conclusion: Pentazocine produces longer duration of meaningful analgesia by all techniques and where epidural route is best.