Last updated on March 2019

Testing Doxazosin to Treat Stress Mechanisms in Alcoholism


Brief description of study

Double-blind, placebo controlled, randomized controlled trial (RCT) for Alcohol Use Disorder examining the effects of doxazosin, a norepinephrine alpha1 receptor antagonist, on stress reactivity and clinical outcomes.

Detailed Study Description

OBJECTIVES
  1. To translate the preclinical evidence from animal models to stress-induced relapse in humans via direct pharmacological antagonism of the noradrenergic system in abstinent alcoholics with doxazosin, an alpha1 noradrenergic receptor blocker.
  2. To screen the efficacy of doxazosin to target stress-related relapse mechanisms in abstinent alcoholics as a cost-effective first step to repurpose this alpha1 noradrenergic antagonist for relapse prevention in addiction.
    PARTICIPANTS

136 participants with an Alcohol Use Disorder in early abstinence.

STUDY OVERVIEW:

136 adults with an Alcohol Use Disorder in early abstinence (1-8 weeks abstinent) will participate in a randomized controlled trial (RCT) to examine the efficacy of 8 mg doxazosin (vs. placebo, between-subjects) on stress reactivity and clinical outcome measures (e.g., drinks/week, alcohol craving) during a 8 week treatment period. We assess doxazosin's impact on stress-related relapse mechanisms using a well-validated human model of stressor reactivity (No Shock, Predictable Shock, Unpredictable Shock [NPU] task) at baseline (pre-treatment) and after 4 weeks of treatment. The NPU task has strong translational ties to both methods (e.g., unpredictable vs. predictable electric shock) and measures (e.g., startle potentiation) from the preclinical literature in animals. This laboratory stress task serves as an attractive early surrogate endpoint post-treatment to assess treatment efficacy and examine stress mechanisms.

AIMS and HYPOTHESIS:

AIM 1: Examine effects of a therapeutic dose of doxazosin on responses to unpredictable stressors in NPU task. The aim is to obtain preliminary evidence via a laboratory surrogate endpoint to repurpose doxazosin for the treatment of stress-induced relapse mechanisms in alcoholism.

PREDICTIONS: Following four weeks of therapeutic dosing, doxazosin (8 mg vs. placebo, between-subjects) will selectively reduce response to unpredictable (vs. predictable) stressors indexed by physiological defensive reactivity (startle potentiation) and self-reported negative affect and craving in abstinent alcoholics.

AIM 2: Examine effects of a therapeutic dose of doxazosin on early clinical outcome measures. The aim is to obtain additional evidence via clinical outcome measures to repurpose doxazosin for the treatment of stress-induced relapse mechanisms in alcoholism.

PREDICTIONS: Following eight weeks of therapeutic dosing, doxazosin (8 mg vs. placebo, between-subjects) will increase continuous abstinence and decrease drinking days per week and drinks per week during the medication treatment period. Doxazosin will also decrease craving measured during the 8th week of medication use when participants have achieved the maximum dose for 4.5 weeks.

AIM 3: Examine predictive validity of pre-treatment laboratory tests of noradrenergic relevant stress-reactivity on surrogate endpoint and clinical outcome measures. The aim is to link individual differences in stress reactivity at baseline (i.e. pre-treatment) to laboratory surrogate endpoints and early clinical outcome measures following therapeutic dosing.

PREDICTIONS: Higher pre-treatment reactivity during unpredictable stressors will predict poorer surrogate endpoint and clinical outcomes overall. Therapeutic 8 mg dose effects of doxazosin will be greater among alcoholics who display higher pre-treatment reactivity to unpredictable stressors.

AIM 4: Examine if the effects of doxazosin on clinical outcome measures are mediated by a reduction of stress-reactivity as measured by the NPU task. The aim is to identify whether reductions in stress-reactivity (NPU task) is the mechanism through which doxazosin has its effect on drinking behavior (clinical outcome).

PREDICTIONS: The direct effect of doxazosin (vs. placebo) following 8 weeks of therapeutic 8 mg dosing on clinical outcomes (e.g., continuous abstinence, drinking days/week, drinks/week) will be partially mediated by the indirect effect of doxazosin on surrogate endpoint of NPU stress reactivity at 4 weeks.

Clinical Study Identifier: NCT02989493

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University of Wisconsin

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