Prazosin and Naltrexone (PaN) Study for Veterans With Alcohol Use Disorders

The purpose of this study is to evaluate whether the combination of prazosin and naltrexone will decrease alcohol cravings and drinking in individuals who have problems with alcohol and have used alcohol at risky levels compare to naltrexone and placebo (Nal/Pl), prazosin and placebo (Praz/Pl), and double-placebo (Pl/Pl). We hypothesize that those assigned to both prazosin and naltrexone would report significantly greater decreases in percent drinking days and heavy drinking days as well as significantly greater reduction in craving from pre to post-treatment than those assigned to either single medication or double-placebo. Prazosin is a medication that is approved by the U.S. Food and Drug Administration (FDA) to treat people with high blood pressure. Some studies have shown that prazosin may also decrease nightmares and improve sleep in Veterans suffering from Posttraumatic Stress Disorder (PTSD). Animal studies have consistently found that prazosin is associated with decreased alcohol consumption and that the combination of prazosin and naltrexone outperforms either medication alone. The current study is evaluating an "off-label" use of prazosin to determine whether it is helpful in decreasing alcohol cravings and consumption among people with alcohol problems. "Off-label" means that the FDA has not approved the use of prazosin for alcohol problems. Naltrexone is a medication that is FDA approved for treating alcohol problems. This study is sponsored by the Department of Defense and the Congressionally Directed Medical Research Program (DoD/CDMRP). We expect approximately 120 participants in this study, which will run over approximately 4 years. Study participants will be involved in the study for 7 weeks, or until they complete the Final Assessment.

In this double-blind, double-dummy, placebo-controlled study of prazosin and naltrexone, we will evaluate the combination of naltrexone and the noradrenergic medication prazosin (Nal/Praz) relative to naltrexone and placebo (Nal/Pl), prazosin and placebo (Praz/Pl), and double-placebo (Pl/Pl). Participants will undergo two craving inductions, one oriented towards relief craving and the other towards reward craving. Daily IVR (Interactive Voice Recording System) data on craving and consumption and PTSD symptomatology will be collected during the 7 days immediately following the initial assessment visit to establish a pre-medication baseline. One hundred twenty individuals with adequate IVR compliance and whose screening lab tests indicate it is safe for them to take the study medications will enter the medication phase of the study within 14 days of the initial assessment initiating prazosin/placebo as well as 50mg naltrexone/placebo treatment. Randomization will be blocked by gender, PTSD status, and desire to abstain vs. desire to cut down. Prazosin will be titrated to three times daily dosing (9 am: 4mg; 3pm: 4 mg; 9pm: 8mg) at the end of two weeks. Naltrexone will be taken once daily 50 mg/day with no titration schedule. The stable dose of both medications will continue for four more weeks and medication compliance will be evaluated through pill counts, the IVR daily monitoring, and riboflavin trace in urine analysis. On approximately day 42 participants will come into the lab for the craving inductions (there will be a two week window after day 42 in which participants may still be seen if scheduling issues arise). The order of the craving inductions will be counterbalanced, and their administration will be separated in time by 30 minutes to minimize carry over between them. Subjective responses to the craving inductions will be obtained via relief oriented craving items and reward oriented craving items from the Desire for Alcohol Questionnaire. Participants will then be assisted in returning their craving levels to baseline prior to debriefing. They will all be offered treatment referrals within the Veterans Affairs (VA) or in the community. Both prazosin and naltrexone can be safely discontinued without tapering.