Single bolus of midazolam versus bolus midazolam plus meperidine for colonoscopy: a prospective, randomized, double-blind trial

Background: The aim of this study was to determine whether a single bolus of meperidine in addition to midazolam improves patient tolerance during colonoscopy. Methods: Consecutive patients undergoing outpatient colonoscopy were randomly assigned in double-blind fashion to receive a single rapid intravenous bolus of 5 mg of midazolam and placebo (Group A, n = 125) or 5 mg midazolam plus 50 mg meperidine (Group B, n = 128). Tolerance (4-point scale: 1 excellent, 4 unbearable), pain (4-point scale: 1 none, 4 severe) and willingness to undergo another colonoscopy were assessed 24 to 48 hours later in a telephone interview conducted by an independent observer blinded to the regimen of sedative medication. Results: Significantly more patients in Group A reported moderate or severe pain (28% vs. 9%; p < 0.001), poor or unbearable tolerance (18% vs. 6%; p < 0.01) and unwillingness to undergo colonoscopy again in the future (14% vs. 5%; p < 0.05). By multivariate analysis, randomization to the midazolam group and younger age were the only variables independently associated with the risk of reporting at least one of these outcomes. Recovery time, frequency of oxygen desaturation, and need for supplemental oxygen were not significantly different between the 2 groups. Conclusions: The addition of a single bolus of meperidine to midazolam improves patient tolerance and lessens pain during colonoscopy without significantly increasing the frequency of side effects or prolonging recovery time.