Jeffrey Panko NP Psychiatry · Patient education
Prazosin
Minipress / Generic capsules
A guide for adults taking prazosin.
Follow the directions on your prescription and your provider's recommendations.
Formulations: Oral capsules have different schedules for blood pressure and nightmares. A low starting dose and gradual adjustment reduce first-dose fainting risk.
What it is used for
Prazosin is approved for high blood pressure. In psychiatry it is used off-label for PTSD-related nightmares. Evidence and guideline support for nightmares do not establish it as treatment for every PTSD symptom.
How it works
It blocks alpha-1 adrenergic receptors, reducing some effects of norepinephrine. Blood vessels relax, which can lower blood pressure and cause dizziness or fainting.
What to expect over time
Nightmares may improve as the dose is adjusted over several weeks. Track frequency, intensity, sleep disruption, and daytime function. Persistent symptoms should prompt review of the broader PTSD and sleep plan.
Taking your medication
- Follow the prescribed schedule; nightmare treatment often begins at bedtime.
- Stand up slowly, particularly after the first dose or a dose increase.
- Do not double a missed dose. After several missed days, ask whether a lower restart dose is needed.
- Do not increase because of one difficult night.
When to get help
Emergency symptoms. Get emergency care for collapse with chest pain, severe injury after fainting, severe allergy, or a painful erection lasting four hours.
Prompt medical advice. Report recurrent dizziness, fainting, falls, or persistent palpitations promptly.
If you feel unsafe or have thoughts of self-harm, call 911 or go to an emergency department.
Possible side effects
- Dizziness or lightheadedness
- Headache, fatigue, or drowsiness
- Low blood pressure or fainting
- Nasal congestion or nausea
Keeping track of treatment
Some side effects resolve with time; others may require a change of medication. Discuss persistent or bothersome side effects with your provider.
Have blood pressure checked, including standing symptoms. Report falls, near-fainting, or a major change in fluid intake or other blood-pressure medicines.
If you take too much
For a suspected overdose, call Poison Control at 1-800-222-1222 immediately, even if you feel well. Call 911 for a seizure, collapse, trouble breathing, or inability to wake.
Before you start
Discuss low blood pressure, fainting, heart disease, and kidney disease. Tell an eye surgeon before cataract surgery, even if you used prazosin in the past.
Discuss pregnancy, pregnancy plans, and breastfeeding with your provider. Treatment decisions should consider both the medication and the condition being treated.
Medicines and interactions
Review all your medications with your provider, including over-the-counter medicines and supplements. Have new medications checked before taking them.
Other blood-pressure drugs, sildenafil or related medicines, alcohol, and dehydration can increase fainting risk.
Review sedatives that may add falls or impaired alertness.
Everyday tips
Keep the route to the bathroom clear.
Record nightmares and dizziness together so benefit and tolerability can be judged.
Your questions answered
Will it treat all of my PTSD?
It targets nightmares for some people. Trauma-focused therapy and other treatments may still be needed.
What if I get up during the night?
Sit at the edge of the bed first, stand slowly, and use adequate lighting to reduce falls.
Storage and safety
Keep medication in its labeled container, away from excess heat and moisture and out of reach of children and pets. Do not share it. Ask a pharmacy about disposal of unused medication.
Sources
About this information
Educational handout; does not replace your prescription or provider's recommendations.
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.