Terazosin (Hytrin®) is an alpha blocker used for treatment of symptoms of prostate enlargement (BPH). It also acts to lower the blood pressure, so is a drug of choice for men with hypertension and prostate enlargement.
It works by blocking the action of adrenaline on smooth muscle of the bladder and the blood vessel walls.
Most common side effects include dizziness, drowsiness, headache, constipation, loss of appetite, fatigue, nasal congestion or dry eyes, but they generally go away after only a few days of use. Sexual side effects are rare, but may include priapism or erectile dysfunction.
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Terazosin - Familydoctor.org - Information for patients in English and Spanish.