Effect of continuous low‐dose intravenous diltiazem on epidural fentanyl analgesia after lower abdominal surgery

Background. The postoperative opioid-sparing effects of systemic L-type calcium channel blockers are controversial. We investigated whether the postoperative analgesic effect of epidural fentanyl was enhanced by i.v. infusion of diltiazem at a rate that would minimize any cardiovascular depressant effect. Methods. After elective lower abdominal gynaecological surgery, 30 patients were randomized to receive continuous i.v. diltiazem 1 µg kg –1  min –1 (diltiazem group) or the same volume of saline (control group) for 24 h. Cumulative postoperative epidural fentanyl consumption, visual analogue scale (VAS) scores and verbal rating scores (VRS) at rest and during mobilization, sedation scores, incidence of side-effects and overall patient satisfaction were assessed. Results. There was no significant difference in cumulative epidural fentanyl consumption between the groups at any period. Although there were no statistically significant differences in VAS scores, VRS, sedation scores, incidence of side-effects and overall patient satisfaction, there was a trend to an increased incidence of nausea in the diltiazem group. Conclusion. Continuous i.v. infusion of diltiazem did not reduce epidural fentanyl consumption when administered at dosages having minimal haemodynamic depressant effects. Br J Anaesth 2003; 90 : 507–9