Superiority of split dose midazolam as conscious sedation for outpatient colonoscopy

World J Gastroenterol. 2009 Aug 14;15(30):3783-7. doi: 10.3748/wjg.15.3783.


Aim: To elucidate the efficacy and safety of a split dose of midazolam in combination with meperidine for colonoscopy.

Methods: Eighty subjects undergoing outpatient colonoscopy were randomly assigned to group A or B. Group A (n = 40) received a split dose of midazolam in combination with meperidine. Group B (n = 40) received a single dose of midazolam in combination with meperidine. Outcome measurements were level of sedation, duration of sedation and recovery, degree of pain and satisfaction, procedure-related memory, controllability, and adverse events.

Results: Group A had a lower frequency of significant hypoxemia (P = 0.043) and a higher sedation score on withdrawal of the endoscope from the descending colon than group B (P = 0.043). Group B recovered from sedation slightly sooner than group A (P < 0.002). Scores for pain and memory, except insertion-related memory, were lower in group A one week after colonoscopic examination (P = 0.018 and P < 0.030, respectively). Poor patient controllability was noted by the endoscopist and nurse in group B (P = 0.038 and P = 0.032, respectively).

Conclusion: Split dose midazolam in combination with meperidine resulted in a safer, more equable sedation status during colonoscopic examination and a reduction in procedure-related pain and memory, but resulted in longer recovery time.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Analgesics, Opioid / therapeutic use*
  • Anesthesia Recovery Period
  • Anesthetics, Intravenous / therapeutic use
  • Colonoscopy / adverse effects*
  • Conscious Sedation / methods*
  • Drug Administration Schedule
  • Drug Therapy, Combination
  • Female
  • Humans
  • Hypnotics and Sedatives / therapeutic use*
  • Male
  • Meperidine / therapeutic use*
  • Midazolam / therapeutic use*
  • Pain Measurement
  • Treatment Outcome
  • Young Adult


  • Analgesics, Opioid
  • Anesthetics, Intravenous
  • Hypnotics and Sedatives
  • Meperidine
  • Midazolam