Adjunctive Sedative Is Safe for Chronic Opioid Users Undergoing Colonoscopy
Diphenhydramine is safe and effective as an adjunctive sedative for chronic opioid users who are undergoing colonoscopy, according to a recent study.
Findings from the study were presented by Dr Salman Nusrat on October 16, 2017, at the World Congress of Gastroenterology at the American College of Gastroenterology (ACG) 2017.
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Chronic opioid use has led to increased tolerance to commonly used sedatives, making sedation difficult in patients on opioids. Due to its hypnotic and sedative properties, diphenhydramine is often used among patients who are difficult to sedate. However, existing data regarding its use in patients taking opioids is conflicting.
For their study, Dr Nusrat and colleagues evaluated individuals on opioids for chronic pain who were scheduled to undergo a colonoscopy. Chronic opioid use was defined as the use of at least 5 mg of morphine or its equivalent at least 3 days per week for more than 3 months.
Participants were randomly assigned to receive either 50 mg diphenhydramine (n = 61) or placebo (n = 58) at the start of the colonoscopy. Intravenous fentanyl and midazolam were administered to participants to help achieve moderate sedation.
Data on baseline characteristics, the amount of fentanyl and midazolam administered, procedure-related time points, and adverse events were collected and recorded. Physicians and nurses assessed the effectiveness of sedation, both qualitatively (inadequate, adequate, over-sedated) and quantitatively (1 = no sedation; 7 = optimal sedation). Furthermore, patients rated pain levels on a 10-point scale (1 = no pain; 10 = severe pain).
Continuous variables were compared using a 2-sided t-test and categorical variables using a chi-square test. The researchers considered a P value of less than 0.05 to be statistically significant.
Baseline characteristics were similar between groups. Results showed that there had been no difference in amount of fentanyl (p = .88) and midazolam (p = .79) used in both groups. However, the mean sedation scores, as well as patient scores for pain and amnesia, had been statistically significant in favor of diphenhydramine.
Qualitative assessment showed that there had been no significant differences between the diphenhydramine and placebo groups. Additionally, they observed no statistical difference in induction time, procedure duration, or recovery times between groups. However, they found that episodes of hypotension were more common among patients on placebo.
“In patients on chronic opioids administration of diphenhydramine at the start of colonoscopy as an adjunct to conventional sedatives improves the quality of sedation without increasing the number of adverse events,” the researchers concluded.
—Christina Vogt
Reference:
Nusrat S. Use of diphenhydramine as an adjunctive sedative for colonoscopy in patients on chronic opioids: a randomized controlled trial. Paper presented at: World Congress of Gastroenterology at ACG2017; October 13-18, 2017; Orlando, FL. https://www.eventscribe.com/2017/wcogacg2017/fsPopup.asp?Mode=presInfo&PresentationID=305005.