Minipress (prazosin), a drug commonly used to treat high blood pressure and urinary retention, has been shown in some studies to be safe and effective in managing nightmares and sleep disturbances in people with post-traumatic stress disorder (PTSD).

Minipress appears to block the production of norepinephrine, a chemical that triggers the body’s “fight or flight” response to threats, both real and perceived. By doing so, people with PTSD may enjoy fewer nightmares without interfering with their blood pressure (as many sedatives do).

Minipress does not seem to have any effect in reducing nightmares in people without PTSD.

This article explains the causes of nightmares in people with PTSD and how Minipress can help. It also takes a look at the evidence supporting the claims and lists the possible risks and side effects of this off-label PTSD drug.

How Common Is PTSD?

Historically, only veterans coming home from combat were diagnosed with PTSD. Now, clinicians recognize patients who experience other types of traumatic events can also suffer from this debilitating mental condition.

Women are more than twice as likely as men to develop PTSD after experiencing or witnessing a traumatic event. Aside from the triggering event, a diagnosis of PTSD requires symptoms in each of four categories:

  • Re-experiencing the event through unwanted memories, nightmares, flashbacks, or strong reactions to reminders of the event
  • Avoiding reminders of the trauma, including people, places, and objects
  • Negative changes in your mood and thoughts associated with the triggering event
  • Chronic hyperarousal symptoms, which may include irritability, aggression, risk-taking, or hypervigilance

How Prazosin Works to Treat Nightmares

Prazosin blocks norepinephrine, a stress hormone that affects your brain, at specialized chemical receptors called alpha-1 receptors. Receptors are the sites where cells transmit messages to each other. It is not clear how this specifically impacts sleep or dreams.

Other Therapeutic Uses

Clinical studies show prazosin might offer other therapeutic benefits to PTSD patients, but the results are mixed. One study suggested that taking prazosin:

  • Significantly reduced daytime PTSD symptoms when military personnel already taking it took it in the daytime too.May have a beneficial effect on alcohol cravings for participants who were alcohol dependent and trying to stop drinking. This is important when you consider the number of PTSD patients who turn to alcohol for comfort and end up with an alcohol use disorder.

Who Should Not Use Prazosin

There are only a few circumstances where you should not take prazosin or use it with caution:

  • If you have previously had adverse reactions to this or similar medications, don’t take prazosin.
  • If you’re going to have cataract surgery, take prazosin with caution.
  • Prazosin should be used with caution if you have low blood pressure.

Of course, your physician can help you determine whether these circumstances apply to your case.

Common Side Effects

Prazosin can cause side effects. In clinical trials, these included:

  • Drowsiness in 8% of patientsLack of energy in 7% of patientsWeakness in 7% of patientsDizziness in 10% of patientsNausea in 5% of patientsPalpitations (irregular heartbeats) in 5% of patientsHeadache in 8% of patients

Additional side effects of prazosin that occur in 1–4% of patients include:

  • VomitingDiarrhea and/or constipationOrthostatic hypotension (a form of low blood pressure triggered by standing up from a seated position too quickly)DepressionNasal congestionFainting

Safety Precautions

As described above, certain people should use prazosin with caution or not at all. The safety of its use while pregnant or breastfeeding is not known, so these populations should use caution. It may also be important to monitor your blood pressure with prazosin use so that it does not become too low and cause fainting or falls.

A Word From Verywell

If you experience any difficulties, you should be in close contact with your primary healthcare provider. PTSD is a serious condition and it deserves treatment. Don’t suffer in silence: reach out to get the help that you need to sleep more normally. If you suffer from depression or experience thoughts of suicide, dial 988 to contact the 988 Suicide & Crisis Lifeline and connect with a trained counselor. If you or a loved one are in immediate danger, call 911.