Timing of pre-emptive tenoxican is important for postoperative analgesia

Purpose: In this prospective randomized study a comparison was made between the efficacy of 20 mg tenoxicam, administered either, 30 min preoperatively or at induction of anesthesia, for the relief of postoperative pain in patients undergoing ambulatory breast biopsy. Methods. Seventy-three patients were recruited and all received a standard anesthetic consisting of induction with 2 mg.kg(-1) propofol followed by 5 mug.kg(-1) alfentanyl. No premedication was administered and at the end of the procedure the wounds were infiltrated with 10 ml of bupivacaine (0.5 %). Patients were randomized to receive 20 mg tenoxicam intraveneously either 30 min before surgery or at induction of anesthesia. Results: Demographic criteria were similar in both groups. There were differences in pain scores at 30, 60, 120 and 240 min postoperatively (VAS at 30 min 3.2 +/- 1.2 vs 5.5 +/- 1.8; P < 0.001: VAS at 60 min 1.8 +/- 1.2 vs 3.7 +/- 1.9, P < 0.001: VAS at 120 min 0.9 +/- 0.9 vs 1.7 +/- 1.0: P = 0.003: VAS at 240 min 0.5 +/- 0.5 vs 1.1 +/- 0.8; P < 0.001: Expressed as mean +/- SD). There was a difference in the number of patients requiring additional analgesia, in the first four hours postoperatively (12 (33%) vs 27 (73%); P = 0.001) and a difference in the time to additional analgesia in these patients (87.5 +/- 32.5 vs 55.0 +/- 26.8 min: P = 0.002). Conclusion: Early administration of pre-emptive tenoxicam 30 min before induction of anesthesia improves postoperative analgesia in patients undergoing ambulatory breast biopsy.