About terazosin
Alpha-1 adrenergic blocker
Used for
- High blood pressure
- Symptoms of an enlarged prostate, such as difficulty urinating
Usual adult dose
High blood pressure: usually 1 mg once daily initially, increased gradually; commonly 1–5 mg daily. Enlarged prostate: usually 1 mg at bedtime initially, increased gradually to 5–10 mg daily.
Common side effects
- Dizziness or light-headedness
- Low blood pressure, especially when standing
- Weakness or tiredness
- Headache or nasal congestion
Important warnings
- Can cause fainting, particularly after the first dose or dose increases.
- Dose increases should be gradual; restarting after several missed days may require a lower dose.
- May cause dizziness; caution with driving until effects are known.
- Seek urgent care for a prolonged, painful erection.
Pregnancy
Not generally used for high blood pressure in pregnancy; discuss treatment options with a clinician.
Breastfeeding
Limited information is available; use only if a clinician considers it necessary.
Interactions
- Other blood-pressure medicines may increase low blood pressure.
- Sildenafil, tadalafil, and similar medicines may cause additional blood-pressure lowering.
- Other alpha-blockers may increase dizziness or fainting risk.
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 It may be incomplete or out of date.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.