A non-randomized pilot trial of the use of prazosin in the prevention of transition from acute stress disorder to post-traumatic stress disorder.

BACKGROUND

Following a traumatic event, 40-80% of the patients with acute stress disorder (ASD) will develop post-traumatic stress disorder (PTSD), 67% at 6 months. Alpha1-blockers are effective in treating some symptoms of PTSD but their usefulness in acute stress situations remains unclear. We hypothesized that reducing noradrenergic hyperactivity with an alpha1-blocker during the acute phase after a traumatic event could prevent the transition to PTSD in patients with ASD.

OBJECTIVE

To investigate the efficacy and safety of a 1-month course of alpha1-blocker (prazosin) to prevent the transition to PTSD in patients with ASD at 6 months.

METHOD: In a monocentric open-label prospective pilot study, 15 patients with ASD were included within 3-7 days of exposure to a traumatic event. After enrolment, they received prazosin LP at home at bedtime at 2.5 mg/day for 7 days and then 5 mg/day for 21 days. Incidence of PTSD was assessed at 6 months using the Clinician Administrated PTSD Scale (CAPS).

RESULTS

At 6 months, 22% of patients who completed the study (2/9) met the diagnostic criteria for PTSD. This rate was significantly lower than that observed in previous studies (67%; p = .047). The treatment was well tolerated and there were no serious adverse events.

CONCLUSIONS

These preliminary findings indicating the safety of prazosin and suggesting its potential to prevent the development of PTSD in ASD require to be replicated in large-scale randomized placebo-controlled studies.Trial registration: The study was pre-registered on a public database (www.clinicalTrials.gov identifier: NCT03045016).