Diphenhydramine as an Adjunctive Sedative in Patients on Chronic Opioids
Condition: Colonoscopy; Adjunct Anesthesia Medication
Study type: Interventional
Phase: Phase 4

Summary: 
      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.
    

Detailed description: 
      Specific Aims:

      The primary aim of our study is to determine if addition of Diphenhydramine to Fentanyl and
      Midazolam will decrease the dose of Fentanyl and Midazolam used during colonoscopy in
      individuals on chronic opioids. Secondarily we will be looking at quality of sedation,
      duration of colonoscopy, time to reach cecum and adverse effects (hypoxia defined as O2
      saturation less than 89% lasting for more than 30 seconds, hypotension defined as systolic BP
      less than 90 mmhg and use of reversal agents i.e Naloxone or Flumazenil).

      Day of Procedure:

      After consent is obtained the medical records of the patients will be reviewed and
      demographic information, co-morbidities, current medication will be extracted and recorded.

      On the day of colonoscopy Alcohol use disorder inventory (AUDIT) will be used to screen for
      alcohol abuse. AUDIT was developed by World Health Organization and has been validated over a
      period of 2 decades. It consist of 10 questions, each question is scored 0-4 on the basis of
      subjects alcohol use. It takes about 2-4 minutes to complete. A score 10 or greater is highly
      specific or alcohol use.

      Subjects will be checked in and prepared according to routine protocols of the VA medical
      center. Participants will be randomly assigned to receive either 50 mg of diphenhydramine or
      10 ml of 0.9% sodium chloride. On the day of colonoscopy randomization will be performed by
      an independent investigator who is a pharmacist at VA medical center using the website
      http://www.randomization.com. She will also prepare and dispense medication. Each endoscopy
      team will consist of an attending gastroenterologist, gastroenterology fellow and two nurses.
      Medications will be administered by one of the nurses under the direct supervision of the
      physician.

      At the start of procedure baseline vitals will be recorded as per our unit's policy. Research
      medication will be administered 3 minutes prior to administration of other medications.
      Neither the patient nor the medical staff including the endoscopist will be aware of the
      contents of the vial. Conscious sedation will be achieved using a combination of intravenous
      midazolam and fentanyl as standard sedative. Rarely, additional diphenhydramine will be
      given, on the basis of the judgment of the endoscopist. During the procedure vital signs
      including oxygen saturation will be monitored at 3-5 minute interval. Procedure related
      complications, including hypotension, desaturation and cardiac arrhythmia will be managed
      according to our endoscopy unit policy and protocols.

      Following the procedure, the nurse and the fellow or the attending will individually rate the
      quality if sedation on a ten-point Likert scale. Qualitative assessment will also be made
      (Under-sedated, adequately sedated, or over-sedated).

      Recovery time will be recorded.

      Day Following the Colonoscopy Twenty-four hour discharge a follow up call will be made and
      the patients will be asked to evaluate the level of sedation on a 10-point scale (1,
      inadequate; 10 completely without discomfort); pain (1, no pain; 10 severe pain), and amnesia
      (10, no memory of the procedure; 1 complete memory).
    

Intervention name(s): Diphenhydramine; Placebo
Intervention type(s): Drug; Drug
Other intervention name(s): Benadryl; Normal Saline; 0.9% sodium chloride
Intervention MeSH terms: Diphenhydramine; Promethazine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Supportive Care
Keywords: Fentanyl; Midazolam; Sedation; Patient tolerance; Duration of colonoscopy