A prospective, randomized, double blind, comparative study of intramuscular nalbuphine hydrochloride, butorphanol tartrate and pentazocine lactate for post-operative pain relief following abdominal hysterectomy

Abstract

Background: This study aimed to compare the efficacy and safety of intramuscularly administered nalbuphine, butorphanol and pentazocine for post-operative pain relief after abdominal hysterectomy. Methods: Seventy-five adult female patients, aged between 20-50 years, belonging to American Society of Anaesthesiologists (ASA) class 1 and 2, posted for abdominal hysterectomy under spinal anesthesia were included in the study. The subjects were randomly divided into 3 groups (n=25 each) and given – Group A: pentazocine lactate (30 mg, 1mL), Group B: butorphanol tartarate (2 mg, 1 ml) and Group C: nalbuphine hydrochloride (10 mg, 1 mL) when post-operative pain intensity reached ≥4 mm on the Visual analogue scale (VAS). The onset, duration, time to peak effect and adverse events were recorded at regular intervals for 24 hours, postoperatively. Results: The mean time to onset of anesthesia was significantly faster (P<0.05 each) in the nalbuphine (10.2±2.2 minutes) and butorphanol (11.3±2 minutes) groups when compared to the pentazocine group (14±2.7 minutes). Duration of analgesic action was significantly longer (P<0.05 each) in the nalbuphine (236.4±75.1 minutes) and butorphanol (202±59.2 minutes) groups when compared to the pentazocine group (177.4±55.3 minutes). No significant differences in respiratory and cardiovascular parameters were noted between the groups. Nausea and vomiting was seen significantly higher in the pentazocine group (36%) when compared to butorphanol (20%) and nalbuphine (8%) groups (p<0.05 each). Conclusions: Intramuscular nalbuphine and butorphanol provided effective analgesia with rapid onset and longer duration of action, with lower incidence of nausea and vomiting when compared to pentazocine. In particular, nalbuphine can be a suitable agent to provide post-operative pain relief in gynecologic lower abdominal surgery.