Centrally acting anticholinergic drug trihexyphenidyl is highly effective in reducing nightmares associated with post‐traumatic stress disorder

INTRODUCTION: Following a case study on scopolamine butyl bromide, an anticholinergic drug, we studied the effect of a central anticholinergic drug on post‐traumatic stress disorder (PTSD)‐related flashbacks and nightmares. METHODS: We administered trihexyphenidyl (TP) to 34 patients with refractory PTSD‐related nightmares and flashbacks (open‐label trial [n = 22]; single‐blind trial [n = 12]), who had previously received psychiatric treatment for approximately 2–15 years, without therapeutic benefits. The effect of TP was determined using the Clinician‐Administered PTSD Scale (CAPS) and the Impact of Event Scale‐Revised (IES‐R). RESULTS: Overall, most patients reported an improvement to none or mild on the CAPS for nightmares (88%) and flashbacks (79%). CONCLUSION: This study is the first to demonstrate the potential efficacy of TP in the treatment of refractory PTSD‐related nightmares and flashbacks. Further double‐blind, randomized control trials are needed to explore the potential clinical benefits of TP in PTSD.