Early Discontinuation and Suboptimal Dosing of Prazosin: A Potential Missed Opportunity for Veterans With Posttraumatic Stress Disorder

Objective: Clinical Practice Guidelines issued by the US Department of Veterans Affairs (VA) and the Department of Defense recommend prazosin for sleep/nightmares for veterans with posttraumatic stress disorder (PTSD). As existing literature suggests this novel treatment option to be underutilized, we examined a cohort of veterans with PTSD initiating prazosin to characterize their typical duration of use and dosing patterns.

Method: Administrative data from fiscal year 2010 were used to identify veterans with PTSD according to ICD-9 codes extracted from inpatient and outpatient encounters. The longitudinal course of prazosin use following initiation was examined using refill data, and estimated prazosin doses were calculated based upon total milligrams and the day’s supply dispensed.

Results: A total of 12,844 veterans with PTSD initiated prazosin during 2010. Twenty percent of veterans never refilled the initial prescription, and 37.6% persisted on the drug for at least 1 year. Patients more likely to remain on prazosin for at least 1 year were older (ages 40-59 years [OR = 1.28; 95% CI, 1.15-1.45] and ages ≥ 60 years [OR = 1.25; 95% CI, 1.12-1.40]) relative to younger patients and taking more medications (4-6 [OR = 1.40; 95% CI, 1.27-1.55], 7-9 [OR = 1.73; 95% CI, 1.56-1.94], and ≥ 10 [OR = 2.04; 95% CI, 1.83-2.29]) relative to 0-3 medications. The mean maximum prazosin dose reached in the first year of treatment was 3.6 mg/d, and only 14.1% of patients reached the minimum guideline recommended dose of 6 mg/d.

Conclusions: Of patients with PTSD newly initiated on prazosin in 2010, < 40% were still taking the drug 1 year later, and < 20% received the minimum recommended dose according to current VA guidelines. Further investigation is required to determine the precise clinical factors underlying these prescribing patterns and overcome barriers to guideline-concordant treatment.