NASHVILLE, Tenn. (WZTV) — A drug treating PTSD in our veterans could be killing them. Prazosin is a blood pressure medication commonly prescribed to treat PTSD nightmares,according to a WZTV news investigation. Only two drugs are approved by the FDA to treat PTSD, and Prazosin is not one of them. Retired Sgt. Allen Chapman said he takes 10 pills a day to treat depression, PTSD, and all the other side effects that come with working in a war zone overseas.