a sexually abused population, participants were mostly female although there are instances where this is not the case. For studies in populations with mixed trauma type, the sex was also generally mixed.


The committee identified a small number of studies examining the effects of prazosin, an alpha-adrenergic blocker, on posttraumatic stress disorder (PTSD). Only two studies met inclusion criteria, and in neither was PTSD the primary outcome. Trauma for participants in both studies was combat-related (primarily from the Vietnam War). The mean age of participants was approximately 55 years. Neither study directly reported the duration of illness but clearly time of exposure was during the war the participant was involved in. In the study that reported race/ethnicity, 73 percent of participants were white (Raskind et al., 2007). The length of treatment in the two studies was 9 and 8 weeks, respectively.

The single randomized trial meeting inclusion criteria was small and focused on nightmares and sleep disturbance as the primary outcomes (Raskind et al., 2007), demonstrating improvement in those completing treatment. Total Clinician Administered PTSD Scale (CAPS) scores were not significantly different between treatment and control patients at the end of the trial. There also was a small (n = 10) crossover study (Raskind et al., 2003) that focused on sleep disturbance with similar results.

Synthesis: The committee found the studies on alpha-adrenergic blockers to be limited in number, and not focused on overall PTSD outcomes. Thus the committee judged the overall body of evidence to be scant and low quality. The committee is uncertain about the presence of an effect, and believes that future well-designed studies will have an important impact on confidence in the effect and the size of the effect.

Conclusion: The committee concludes that the evidence is inadequate to determine the efficacy of prazosin in the treatment of PTSD.


Although the committee judged the evidence inadequate to determine the efficacy of prazosin as a treatment of PTSD in general populations for overall PTSD outcomes, there are two small studies suggesting efficacy for combat-related nightmares and sleep disturbance in veterans.

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