The impact of lofexidine on stress-related opioid craving and relapse: Design and methodology of a randomized clinical trial.

Opioid Use Disorders (OUDs) and drug overdose deaths are increasing at alarmingly high rates in the United States. Stress and dysregulation in biologic stress response systems such as the hypothalamic-pituitary-adrenal axis and noradrenergic system appear to play an important role in the pathophysiology of substance use disorders and relapse to drug use, particularly for women. Alpha-2 adrenergic agonist medications effectively decrease noradrenergic activity and have demonstrated benefit in preventing relapse to substance use and decreasing stress-reactivity and craving in cocaine- and nicotine-dependent women, compared to men. Alpha-2 adrenergic agonists may help decrease stress reactivity in individuals with OUDs and prevent relapse to drug use, but gender differences have yet to be systematically explored. We describe the rationale, study design and methodology of a randomized, double-blind, placebo-controlled clinical trial examining gender differences in stress, craving and drug use among adult men and women with OUD taking methadone or buprenorphine and randomly assigned to an alpha-2 adrenergic agonist, lofexidine, compared to placebo. In addition, we describe methods for measuring daily stress, craving and drug use in participant's natural environment as well as participant's physiological (i.e., heart rate, cortisol) and psychological (i.e., stress, craving) response to laboratory social and drug cue stressors. Lastly, we detail methods adopted to sustain research activity while following guidelines for the COVID-19 pandemic. ClinicalTrials.gov Registration Number: NCT03718065.