Prazosin
Prazosin is an alpha-1 adrenergic blocker that relaxes blood vessels by preventing the hormone norepinephrine from constricting them. It is primarily prescribed for the treatment of hypertension (high blood pressure) and may also be used for symptoms of benign prostatic hyperplasia (BPH).
Prazosin is a blood pressure medication that works by relaxing blood vessels through alpha-1 receptor blockade.
Key facts at a glance
- ATC
- C02CA01
- RxNorm
- 8629
- Generic
- Prazosin
- Class
- atc-c02
- Brands
- Minipress
- Availability
- rx
- Pregnancy
- C
- Lactation
- caution
- Routes
- oral
- Forms
- capsule, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Prazosin is used to treat hypertension (high blood pressure), and may be prescribed for benign prostatic hyperplasia (BPH) to improve urinary symptoms. It has also been used off-label for PTSD-related nightmares and Raynaud's phenomenon.
Prazosin blocks alpha-1 adrenergic receptors in the walls of blood vessels, preventing norepinephrine from causing vasoconstriction. This leads to smooth muscle relaxation, dilation of blood vessels, and ultimately lowered blood pressure.
A notable side effect is orthostatic hypotension, particularly after the first dose ('first-dose phenomenon'), so it is usually started at low doses taken at bedtime. Patients should rise slowly from sitting or lying positions. Other common effects include dizziness, headache, and palpitations. Inform your doctor of all medications, especially other blood pressure drugs and erectile dysfunction medications.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy