Colonoscopy | Diphenhydramine as an Adjunctive Sedative in Patients on Chronic Opioids

Colonoscopy research study

What is the primary objective of this study?

To access the efficacy of adding diphenhydramine as adjunct to improve sedation and to reduce the amount of standard sedatives used during colonoscopy in patients on chronic opioids.

Who is eligible to participate?

Inclusion Criteria: - Patients aged 18-64 years undergoing screening, surveillance, diagnostic and therapeutic colonoscopy - Patient on chronic opioids defined as at least 5 mg of morphine or its equivalent at least 3 days per week for more than 3 months Exclusion Criteria: - Inability to execute informed consent - Allergy to Diphenhydramine, fentanyl or midazolam - Known or suspected pregnancy - Endoscopic procedure without sedation - Patient scheduled to have other endoscopic procedures on the same day - Prior alimentary tract surgery - Severe cardiopulmonary disease (ASA IV) - MOI use within 2 weeks of procedure

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?


Adjunct Anesthesia Medication

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.



Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

DiphenhydramineDiphenhydramine 50 mg IV 3 minutes prior to administration of other sedatives

Placebo0.9% sodium chloride 10 ml IV 3 minuted prior to administration of other sedatives

Study Status

Unknown status

Start Date: December 2013

Completed Date: June 2017

Phase: Phase 4

Type: Interventional


Primary Outcome: Dosage of Fentanyl and Midazolam

Secondary Outcome: Quality of sedation

Study sponsors, principal investigator, and references

Principal Investigator: Salman Nusrat, MD

Lead Sponsor: University of Oklahoma


More information:

Abraham NS, Fallone CA, Mayrand S, Huang J, Wieczorek P, Barkun AN. Sedation versus no sedation in the performance of diagnostic upper gastrointestinal endoscopy: a Canadian randomized controlled cost-outcome study. Am J Gastroenterol. 2004 Sep;99(9):1692-9.

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