Prazosin is a medication that is used off-label to treat nightmares and sleep disturbances associated with post-traumatic stress disorder (PTSD) . PTSD is a disorder that can affect a person if they have experienced or witnessed a traumatic event, and it can cause symptoms such as flashbacks, difficulty sleeping, anxiety, irritability, and feelings of guilt and blame. Prazosin works by blocking the alpha-1 adrenoceptor, which reduces the responsiveness of the central nervous system to noradrenaline, a chemical that is involved in the bodys response to stress. This medication has been shown to be effective and safe in the treatment of nightmares and sleep disturbances associated with PTSD. However, it is important to note that prazosin is not FDA-approved for this purpose, and it is used off-label. The recommended starting dose of prazosin is 1 mg before bed, increasing by 1 mg every 2-3 nights until a clinical response is obtained. The average daily doses of prazosin in the treatment of PTSD achieved 19.6 mg for males and 8.7 mg for females, although there are reports of higher doses being used. Prazosin is generally well-tolerated, but common adverse drug reactions include dizziness, headache, drowsiness, lack of energy, weakness, palpitations, and nausea. A significant potential adverse drug reaction is "first-dose syncope," which occurs with doses of 2 mg or higher.