Seattle Institute for Biomedical and Clinical Research
Who can join
Adults 18 to 80, any sex, with Alcohol Use Disorder or Posttraumatic Stress Disorder (PTSD). Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Change in Percent Drinking Days (PDD) (Visit 8 PDD - Visit 2 PDD)Primary· Visit 2 (baseline) and visit 8 (last visit). Per the protocol, visit 8 is scheduled to occur 42 days (± 7days) after visit 2. In reality, visit 8 occurred 35 to 76 days after visit 2 with the average of 45 days due to scheduling difficulties.
PDD was calculated based on self-reported drinking history collected via Form-90. Drinking days were defined as days when participants consumed alcohol. Form-90 was completed by participants in visit 2 (baseline) and visit 8 (last visit). Form-90 collected in the baseline visit recorded participants' alcohol consumption from 90 days prior to their baseline visit until the day before their baseline visit. Form-90 collected in the last visit recorded participants' alcohol consumption from baseline until the day before their last visit. This outcome measures changes in PDD between visit 8 and vis
Group
Value
95% CI
Praz/Nal
-37
± 10
Praz/Pl
-9
± 10
Nal/Pl
-14
± 10
Pl/Pl
-15
± 9
Change in Percent Heavy Drinking Days (PHDD) (Visit 8 PHDD - Visit 2 PHDD)Primary· Visit 2 (baseline) and Visit 8 (last visit). Per the protocol, visit 8 is scheduled to occur 42 days (± 7days) after visit 2. In reality, visit 8 occurred 35 to 76 days after visit 2 with the average of 45 days due to scheduling difficulties.
PHDD was calculated based on self-reported drinking history collected via Form-90. Heavy drinking days were defined as days when participants consumed 4 or more drinks for females and 5 or more drinks for males. Form-90 was completed by participants in the baseline and last visit. Form-90 collected in the baseline visit recorded participants' alcohol consumption 90 days prior to their baseline visit. Form-90 collected in the last visit recorded participants' alcohol consumption from baseline until the day before their last visit. This outcome measures changes in PHDD between visit 8 and visit
Group
Value
95% CI
Praz/Nal
-38
± 17
Praz/Pl
-8
± 17
Nal/Pl
-7
± 17
Pl/Pl
-13
± 16
Change in Alcohol Craving (Visit 8 PACS - Visit 2 PACS)Primary· Visit 2 (baseline) and visit 8 (last visit). Per the protocol, visit 8 is scheduled to occur 42 days (± 7days) after visit 2. In reality, visit 8 occurred 35 to 76 days after visit 2 with the average of 45 days due to scheduling difficulties.
Alcohol craving was assessed in visit 2 (baseline) and the last visit (visit 8) using the Pennsylvania Alcohol Craving Scale (PACS). The PACS had 5 questions, where each question had six options presented in Likert Scales from 0 to 6, with 0 being the least and 6 being the highest possible option, thus the possible minimum and maximum values are 0 and 30, respectively. Higher scores mean higher craving. This outcome measures the change in PACS scores between visits 2 and 8 (visit 8 PACS score - visit 2 PACS score). Per the protocol, visit 8 is scheduled to occur 42 days (± 7days) after visit 2
Group
Value
95% CI
Praz/Nal
-10.5
± 2.4
Praz/Pl
-4.6
± 2.4
Nal/Pl
-4.3
± 2.4
Pl/Pl
-3.5
± 2.4
Change in Mean Drinks Per Day of Drinking (Visit 8 - Visit 2)Secondary· Visit 2 (baseline) and visit 8 (last visit). Per the protocol, visit 8 is scheduled to occur 42 days (± 7days) after visit 2. In reality, visit 8 occurred 35 to 76 days after visit 2 with the average of 45 days due to scheduling difficulties.
Average drinks per day of drinking was calculated based on self-reported drinking history collected via Form-90. Drinking days were defined as days when participants consumed alcohol. Form-90 was completed by participants in visit 2 (baseline) and visit 8 (last visit). Form-90 collected in the baseline visit recorded participants' alcohol consumption 90 days prior to their baseline visit. Form-90 collected in the last visit recorded participants' alcohol consumption from baseline until the day before their last visit. This outcome reports the change in the mean drinks between visit 8 and visit
Group
Value
95% CI
Praz/Nal
-5.1
± 1.7
Praz/Pl
-2.2
± 1.7
Nal/Pl
-5.0
± 1.7
Pl/Pl
-3.7
± 1.6
Adverse events — posted to ClinicalTrials.gov
Time frame: Participants went through 8 in-person visits (screening, baseline, and visits 3 to 8). Adverse events were collected after the baseline visit, the visit where participants were randomized and received medications, through 3 safety calls and 6 visits (visits 3 to 8). There was one safety call after the baseline visit, visit 3, and visit 4. Depending on whether a participant completed the study or not, adverse events were collected from 1 to 11 weeks..
Reporting threshold: 0%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
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.
Publications & conference data
2 peer-reviewed publications reference this trial (live from Europe PMC):
NCT05189977 — A Trial to Assess the Effects of Prazosin or Propranolol on Blood Pressure in the Presence of Brexpiprazole/Sertraline
· Phase 1
· terminated
NCT04793685 — Prazosin for Alcohol Use Disorder With Withdrawal Symptoms
· Phase 2
· recruiting
Publications: Europe PMC API search by NCT ID, retrieved 9 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Seattle Institute for Biomedical and Clinical Research
Last refreshed: 29 December 2020
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT02322047.