Conditions: Substance-Related Disorders
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 15
Healthy volunteers: yes

Brief summary:
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.

Detailed description:
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.

Arms:
arm 1: Some participants received ondansetron pretreatment during the second session, and then placebo during the third session. arm 2: Some participants received placebo pretreatment during the second session, and then ondansetron pretreatment during the third session.

Interventions: intervention 1: Ondansetron
Intervention descriptions: intervention 1: In this cross-over study, the blinded patient will receive saline placebo in one session and ondansetron in the other. The order is decided with a randomization table. If ondansetron is randomly chosen, an 8mg IV Bolus will be given at the start of the study for 30 minutes by the unblinded investigator.

Protocol document: