Functional Magnetic Resonance 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.

Some participants received ondansetron pretreatment during the second session, and then placebo during the third session.

Some participants received placebo pretreatment during the second session, and then ondansetron pretreatment during the third session.

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.

Brain Regions With Increases or Decreases in Amplitude of Low Frequency Fluctuations (ALFF) Associated With Ondansetron Administration

Changes are reporting using Spearman's correlation coefficient, using within-subject factors of time (pre-naloxone, post-naloxone) and pre-treatment (placebo, ondansetron). Changes in Objective Opioid Withdrawal Scale (OOWS) and Subjective Opioid Withdrawal Scale (SOWS) with correlation coefficient >0.45 are reported. The OOWS consists of 13 observable physical symptoms assessed over a 5-minute observation period and scored as present (score of 1) or absent (score of 0). The total OOWS scores is determined by summing the scores of the 13 items. OOWS scores can range from 0 to 13; lower scores correspond to fewer symptoms. SOWS consists of 16 physical and emotional symptoms rated by the participant on a scale from 0 (not at all) to 4 (extremely), to indicate the extent to which the symptom describes how they are feeling at the time. The total SOWS score is determined by summing the scores of the 16 items. Scores range from 0 to 64; lower scores correspond to fewer symptoms.

The OOWS consists of 13 observable physical symptoms that are assessed over a five-minute observation period and scored as present (score of 1) or absent (score of 0). The total OOWS scores is determined by summing the scores of the 13 items. OOWS scores can range from a low of 0 to a high of 13. A score of 0 would suggest that no objective signs of withdrawal were observed while a score of 13 would suggest that every observable sign of withdrawal was observed.

The OOWS consists of 13 observable physical symptoms that are assessed over a five-minute observation period and scored as present (score of 1) or absent (score of 0). The total OOWS scores is determined by summing the scores of the 13 items. OOWS scores can range from a low of 0 to a high of 13. A score of 0 would suggest that no objective signs of withdrawal were observed while a score of 13 would suggest that every observable sign of withdrawal was observed.

Subjective Opioid Withdrawal Scale (SOWS) Score 20 Minutes Following Ondansetron or Placebo Administration

The SOWS consists of 16 physical and emotional symptoms that are rated by the participant on a scale from 0 (not at all) to 4 (extremely), to indicate the extent to which the symptom describes how they are feeling at the time. The total SOWS score is determined by summing the scores of the 16 items. Scores range from a low of 0 to a high of 64. A score of 0 would suggest that the individual is experiencing no symptoms of withdrawal while a score of 64 would suggest that the individual is experiencing all 16 symptoms of withdrawal to the fullest extent possible.

Inclusion Criteria Patients will be healthy male volunteers, ages 18-35. Exclusion Criteria Females were excluded due to menstrual cycle modulation of opioid response. We will exclude individuals with Raynaud's disease or a history of coronary artery disease.

Compton P, Miotto K, Elashoff D. Precipitated opioid withdrawal across acute physical dependence induction methods. Pharmacol Biochem Behav. 2004 Feb;77(2):263-8. doi: 10.1016/j.pbb.2003.10.017.

Compton P, Athanasos P, Elashoff D. Withdrawal hyperalgesia after acute opioid physical dependence in nonaddicted humans: a preliminary study. J Pain. 2003 Nov;4(9):511-9. doi: 10.1016/j.jpain.2003.08.003.

Stein EA, Pankiewicz J, Harsch HH, Cho JK, Fuller SA, Hoffmann RG, Hawkins M, Rao SM, Bandettini PA, Bloom AS. Nicotine-induced limbic cortical activation in the human brain: a functional MRI study. Am J Psychiatry. 1998 Aug;155(8):1009-15. doi: 10.1176/ajp.155.8.1009.

Krystal JH, Woods SW, Kosten TR, Rosen MI, Seibyl JP, van Dyck CC, Price LH, Zubal IG, Hoffer PB, Charney DS. Opiate dependence and withdrawal: preliminary assessment using single photon emission computerized tomography (SPECT). Am J Drug Alcohol Abuse. 1995 Feb;21(1):47-63. doi: 10.3109/00952999509095229.

Williams TM, Daglish MR, Lingford-Hughes A, Taylor LG, Hammers A, Brooks DJ, Grasby P, Myles JS, Nutt DJ. Brain opioid receptor binding in early abstinence from opioid dependence: positron emission tomography study. Br J Psychiatry. 2007 Jul;191:63-9. doi: 10.1192/bjp.bp.106.031120.

Hui SC, Sevilla EL, Ogle CW. Prevention by the 5-HT3 receptor antagonist, ondansetron, of morphine-dependence and tolerance in the rat. Br J Pharmacol. 1996 Jun;118(4):1044-50. doi: 10.1111/j.1476-5381.1996.tb15504.x.

Pinelli A, Trivulzio S, Tomasoni L. Effects of ondansetron administration on opioid withdrawal syndrome observed in rats. Eur J Pharmacol. 1997 Dec 11;340(2-3):111-9. doi: 10.1016/s0014-2999(97)01349-6.

Lowe AS, Williams SC, Symms MR, Stolerman IP, Shoaib M. Functional magnetic resonance neuroimaging of drug dependence: naloxone-precipitated morphine withdrawal. Neuroimage. 2002 Oct;17(2):902-10.

Chu LF, Lin JC, Clemenson A, Encisco E, Sun J, Hoang D, Alva H, Erlendson M, Clark JD, Younger JW. Acute opioid withdrawal is associated with increased neural activity in reward-processing centers in healthy men: A functional magnetic resonance imaging study. Drug Alcohol Depend. 2015 Aug 1;153:314-22. doi: 10.1016/j.drugalcdep.2015.04.019. Epub 2015 May 27.