Nightmares are a highly prevalent and distressing feature of post-traumatic stress
disorder (PTSD). Previous studies have reached mixed conclusions regarding the effects
of prazosin on nightmares, sleep quality and overall PTSD symptoms in patients with
PTSD. MEDLINE, EMBASE, all EBM databases, PsycIFNO and CINAHL were systematically
searched from inception date to October 2018 for randomized clinical trials that included
reporting of nightmares, sleep quality or overall PTSD symptoms. The analysis included
data from eight trials involving 286 PTSD patients in the prazosin group and 289 PTSD
patients in the placebo group. In our meta-analysis, prazosin resulted in a statistically
significant improvement in nightmares (standardized mean difference (SMD) = −1.13,
95% confidence interval (CI) = −1.91 to −0.36), but was not more beneficial than placebo
for overall PTSD symptoms (SMD = −0.45, 95% CI = −0.95 to 0.05) and sleep quality
(SMD = −0.44, 95%CI = −1.44 to 0.55). In terms of acceptability, there was no significant
difference between the prazosin group and the placebo group with respect to discontinuation
for all causes (odds ratio (OR) = 1.00, 95% CI = 0.62–1.62). In conclusion, the use
of prazosin was associated with an improvement of nightmare symptoms. Our findings
indicate that additional studies are needed before considering downgrading the use
of prazosin in the treatment of nightmares in patients with PTSD.