Intraoperative loading attenuates nausea and vomiting of tramadol patient-controlled analgesia

Purpose: To evaluate the adverse effect profile of tramadol by patient-cont rolled analgesia (PCA) with administration of the loading dose either intra operatively or postoperatively. Methods: Sixty adult patients scheduled for elective abdominal surgery were enrolled into this prospective, randomized, double blind study. The patien ts were anesthetized in a similar manner. At the beginning of wound closure , the patients were randomly allocated to receive 5 mg.k(-1) tramadol (Grou p I) or normal saline (Group 2). In the post-anesthesia care unit (PACU), w hen patients in either group complained of pain, 30 mg.ml(-1) tramadol iv w ere given every three minutes until visual analogue scale (VAS) 3, followed by tramadol PCA with bolus dose of 30 mg and five minute lockout interval. Pain control and adverse effect assessments were done in the PACU and ever y six hours for 48 hr post drug by an independent observer. Results: The loading dose was 290 +/- 45 mg in Group 1 and 315 +/- 148 mg i n Group 2. In PACU, more nausea/vomiting both in terms of incidence (13/30, 43% vs 2/30, 6,6%, P < 0.05) and severity (nausea/vomiting score 2.5 +/- 2 .0 vs 0.2 +/- 0.6, P < 0.05) was observed in patients with postoperative lo ading than in those with intraoperative loading of tramadol. Conclusion: Administering the loading dose of tramadol during surgery decre ases the nausea/vomiting associated with high dose of tramadol and improves the quality of tramadol PCA in the relief of postoperative pain.