About prazosin hydrochloride
Alpha-1 adrenergic blocker
Used for
- High blood pressure
- Urinary symptoms from benign prostate enlargement; use may be off-label
Usual adult dose
High blood pressure: usually 1 mg two or three times daily initially, then adjusted gradually. Prostate symptoms: dosing varies.
Common side effects
- Dizziness or light-headedness, especially when standing
- Fainting, particularly after the first dose or dose increases
- Headache or drowsiness
- Palpitations or nausea
Important warnings
- First-dose fainting can occur; doses are increased gradually.
- Can cause low blood pressure when standing, increasing fall risk.
- Use cautiously with other blood-pressure-lowering medicines or erectile dysfunction drugs.
- Not usually a first-choice medicine for high blood pressure.
Pregnancy
Use only when clearly needed; pregnancy safety information is limited. Blood-pressure treatment should be clinician-directed.
Breastfeeding
Information is limited; discuss use with a healthcare professional, particularly when nursing a newborn or premature infant.
Interactions
- Other blood-pressure-lowering medicines can increase dizziness or fainting.
- Sildenafil, tadalafil, and similar drugs can cause marked low blood pressure.
- Alcohol may worsen dizziness and light-headedness.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.