Effect of preoperativeadministration of tramadol controlled release tablets on postoperative acute opioidtolerance in patients after remifentanil-based anesthesia

Abstract

：Objective To investigatethe effect of preoperative administration of tramadol controlled release tablets onpostoperative acute opioid tolerance in patients after remifentanil-basedanesthesia.Methods Sixty ASA Ⅰ or Ⅱ patients aged 18-64 yr undergoing laparoscopiccholecystectomy(LC)under general anesthesia were randomly divided into 2 groups(n = 30each): placebo control group(group C)and tramadol controlled release tablets group(groupT).In group C vitamin C tablets 100 mg was taken orally 48,36,24,12,0.5 h before operationand in group T tramedol controlled release tablets 100 mg was administered orally at thesame time points respectively.Anesthesia was induced and maintained with TCI ofremifentanil(Cp 1.5-6.0 ng/ml)and propofol(Cp 2.5-4.5 μg/ml).The patients wereobserved in PACU for 1 h after LC and then transferred to the ward.Postoperative pain wascontrolled by intermittent iv boluses of fentanyl in PACU.Patient-controlled intravenousanalgesia(PCIA)with fentanyl(loading dose 10 μg,background infusion 20μg/h,bolus dose 5 μg,lockout interval 15 min)wasused in the ward.Fentanyl consumption in PACU during the first hour after operation wasrecorded.Fentanyl consumption of PCIA,the number of successful delivered doses(D_1)and thenumber of attempts(D_2)in the ward during the 48 h after operation were recorded.D_1/D_2ratio was calculated.Results Fentanyl consumption was significantly lower in group T thanin group C during the first hour after operation in PACU(P＜0.05).There was nosignificant difference in fentanyl consumption of PCIA and D_1/D_2 ratio during the48 hafter operation between the two groups(P＞0.05).Conclusion Preoperative administration of tramadolcontrolled release tablets(500 mg)can effectively alleviate early postoperative acuteopioid tolerance induced by remifentanil-based anesthesia. Key words: Tramadol; Delayed-action preparations; Administration,oral; Piperidines; Drug tolerance