Pharmacologic treatments for nightmares are limited. Increased adrenergic hyperresponsiveness has been postulated as a mechanism in the pathophysiology of Post-Traumatic Stress Disorder (PTSD). Prazosin, a central alpha-1 adrenergic receptor antagonist, has been studied for PTSD-related nightmares.

To review evidence for prazosin to treat PTSD and non-PTSD nightmares.

A systematic review using MEDLINE/PubMed, EMBASE, EBM Review, Google Scholar, and Web of Science. Two authors reviewed abstracts and selected clinical reports of prazosin treatment.

Of 115 abstracts, 19 studies met criteria: 3 randomized, double-blind, placebo controlled trials; 3 open label case series; 5 retrospective chart reviews; and 8 case reports. 183 evaluable patients (135 veterans and 48 civilians; 163 males) were described. Only one study did not confirm a PTSD diagnosis, but commented that their patients had symptoms consistent with PTSD. Common outcome measures were the Clinician Administered PTSD Scale (CAPS) items B2 (“recurrent distressing dreams”) and D1 (“difficulty falling or staying asleep”), and the Clinical Global Impression of Change (CGI-C). The CAPS-B2 and CGI-C consistently showed improvement in patients treated with prazosin. There were reports of patients relapsing with nightmares when they discontinued prazosin. Effective dosages ranged from 1 mg to 16 mg. Common side effects included dizziness, and blood pressure changes were not significantly affected. Prazosin was well tolerated, even by elderly patients.

Despite small sample sizes, the evidence supports the use of prazosin for PTSD-related nightmares. However, there was no evidence for its use in non-PTSD nightmares. Future larger studies would be informative.