fMRI Imaging of Opioid Withdrawal in Healthy Human Volunteers
fMRI Imaging of Opioid Withdrawal in Healthy Human Volunteers
Opioid medications are commonly used for pain relief. When given over time, physical dependence can occur. This results in unpleasant side effects--such as agitation and nausea--if opioid medications are suddenly stopped. However, we do not know how withdrawal affects the brain. We know that a medication named Ondansetron can help ease or prevent symptoms associated with opioid withdrawal. Through imaging of the brain by fMRI, we hope to see how opioid withdrawal, with and without the administration of ondansetron, affects brain activity.
During the study, each participant attended three separate lab-based acute opioid withdrawal sessions. The first session was undertaken in a mock MRI scanner and was designed to determine if participants could tolerate withdrawal in the scanning environment. Participants who were able to successfully and safely tolerate opioid withdrawal while in the scanner were approved to continue with the following study sessions. Participants were then pretreated intravenously (IV) with either 0.9% normal saline placebo or 8mg ondansetron. Later, participants in all sessions received IV naloxone (10mg/70kg) to precipitate opioid withdrawal. Participants were assigned to ondansetron or placebo pretreatment conditions in a randomized, double-blinded, and counter-balanced order. Objective Opioid Withdrawal Scale (OOWS) and Subjective Opioid Withdrawal Scale (SOWS) were assessed throughout the study to quantify withdrawal. Study timeline progressed as follows: T=-165, 8mg ondansetron or placebo infusion, T=-135, Morphine infusion (10mg/70kg), T=-41 preparation for MRI, T=-21, start MRI, T=-13, baseline OOWS/SOWS, T=-9, start of fMRI, T=0 Naloxone induced withdrawal, T=5, OOWS, T=15, OOWS, T=20, Retrospective OOWS.
Inclusion Criteria
Exclusion Criteria