Sedation | Randomized Trial of Diphenhydramine Versus Continued Midazolam in "Difficult-to-sedate" Patients Undergoing Colonoscopy

Sedation research study

What is the primary objective of this study?

Patients who are undergoing colonoscopy and are not adequately sedated after initial standard sedation with midazolam 5 mg and fentanyl 100 mcg will be randomly assigned to receive diphenhydramine vs. continued midazolam, and their level of sedation will be assessed. Our hypothesis is that diphenhydramine will provide better sedation than continued administration of midazolam during colonoscopy in patients not achieving adequate sedation with standard doses of midazolam plus fentanyl.

Who is eligible to participate?

Inclusion Criteria: - Patients >18 years-old who are undergoing elective colonoscopy with conscious sedation Exclusion Criteria: - allergy or prior adverse reactions to diphenhydramine - medical contraindications to use of diphenhydramine (e.g. closed angle glaucoma) - pregnancy

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



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.

DiphenhydramineIncrements of 25 mcg to maximum of 3 times (total 75 mcg)

Midazolam1.5 mg increments up to 3 times (maximum 4.5 mg)

Study Status


Start Date: February 2013

Completed Date: April 2016

Phase: N/A

Type: Interventional


Primary Outcome: Number of Patients Who Achieve Adequate Sedation to Allow Colonoscopy (Defined as MOAA/S ≤3)

Secondary Outcome:

Study sponsors, principal investigator, and references

Principal Investigator: Loren Laine, MD

Lead Sponsor: VA Connecticut Healthcare System


More information:

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