The Effect of Physostigmine on Cognitive Functioning in the Immediate Period After Sedation for Colonoscopy


The purpose of this study is to determine whether the administration of physostigmine in combination with sedation for colonoscopy can minimize the cognitive decline at the time of hospital discharge

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: Triple (Participant, Care Provider, Outcomes Assessor)
  • Study Primary Completion Date: July 2011

Detailed Description

Physostigmine, a tertiary cholinesterase inhibitor, which prevents the breakdown of ACh by inhibiting the enzyme acetylcholinesterase (AChE), crosses the blood-brain barrier (BBB), and elevates brain ACh levels. Physostigmine has been shown to improve attention, and performance in working memory. It has also been shown to produce analgesia following systemic or central administration. Patients undergoing colonoscopy under sedation of propofol and fentanyl show cognitive decline in the immediate period following the procedure. In this study, half the patients will receive physostigmine in combination with the sedation, and their cognitive functioning at the time of hospital discharge will be assessed by standard neuropsychological tests, and compared to that of patients without physostigmine.


  • Drug: Physostigmine
    • Intravenous bolus of physostigmine 1 mg, 3-5 minutes before completion of the colonoscopy procedure

Arms, Groups and Cohorts

  • Experimental: Physostigmine
    • Colonoscopy sedation with or without physostigmine

Clinical Trial Outcome Measures

Primary Measures

  • Cognitive functioning assessed by standard neuropsychological tests
    • Time Frame: At time of hospital discharge following colonoscopy procedure

Participating in This Clinical Trial

Inclusion Criteria

  • Over18 years old – ASA I-III – Fluency in Hebrew, Russian, or Arabic – Absence of serious hearing or vision impairment Exclusion Criteria:

  • History of head trauma, neurological diseases, alcoholism, drug abuse, consumption of psychotropic drugs or antidepressants – Heart failure (NYHA > 3) – Liver failure – Respiratory problems (asthma, etc.)

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 80 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Rabin Medical Center
  • Provider of Information About this Clinical Study
    • Prof. Benzion Beilin, Hasharon Hospital, Rabin Medical Center
  • Overall Official(s)
    • Bezion Beilin, MD, Principal Investigator, Hasharon Hospital, Rabin Medical Center
  • Overall Contact(s)
    • Benzion Beilin, MD, 972-3-937-2469,

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