From the Guidelines
Prazosin should be prescribed at a dose of 1-15 mg per night for treating nightmares associated with PTSD or trauma, with a mean dose of 13 ± 3 mg/day being effective in reducing distressing dreams by over 50% compared to placebo 1. The dose of prazosin can be gradually increased as needed and tolerated, with most patients finding benefit at this range.
Key Considerations
- The medication should be taken 30-60 minutes before bedtime for optimal effect.
- Start with the lowest dose to minimize side effects like dizziness, lightheadedness, or low blood pressure, which are most common when beginning treatment or increasing the dose.
- The first dose should be taken when the patient can remain lying down for several hours afterward to avoid falls.
- Prazosin works by blocking alpha-1 adrenergic receptors in the brain, which helps reduce the norepinephrine activity that contributes to nightmares and sleep disturbances.
Monitoring and Precautions
- Blood pressure should be monitored regularly while taking prazosin, especially when adjusting doses.
- Patients should rise slowly from sitting or lying positions to prevent dizziness.
- Improvement may be noticed within days to weeks, but consistent use is important for maintaining benefits.
Evidence Summary
- A position paper from the American Academy of Sleep Medicine found that prazosin was effective in reducing nightmare frequency and distressing dreams in adults with PTSD-associated nightmares 1.
- The study reported a mean dose of prazosin of 13 ± 3 mg/day, with a decrease in distressing dreams item of over 50% compared to placebo.
- Other studies have reported effective doses ranging from 1 to 15 mg per night, with some studies finding no significant difference in outcome measures between prazosin and placebo 1.
From the Research
Dose of Prazosin Associated with Nightmares
- The dose of Prazosin associated with nightmares is usually initiated at 1 mg, with monitoring for hypotension after the first dose, and then gradually increased to maintenance levels of 2-6 mg at night 2.
- Studies of military patients with PTSD have used higher doses, such as 10-16 mg at night 2.
- A therapeutic benefit has been reported with Prazosin dosages as low as 1 mg daily, and suppression of nightmare symptoms has occurred within one week of Prazosin initiation 3.
- The maximum dosage recommendation is 20 mg at bedtime and 5 mg midmorning 4.
- The dose of Prazosin has been found to range from 1 to 16 mg/d in various studies 5.
Efficacy of Prazosin in Treating Nightmares
- Prazosin has been shown to be effective in reducing nightmares related to posttraumatic stress disorder (PTSD) 2, 3, 4, 5.
- Prazosin has been found to be beneficial in treating nightmares associated with burn trauma in the hospital setting 6.
- The efficacy of Prazosin in treating nightmares has been consistently reported in open-label trials, retrospective chart reviews, and single case reports 5.