Indications
Terazosin is used to relieve urinary symptoms of benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate gland in men that causes a weak stream, frequent urination and difficulty emptying the bladder. It is also used, alone or with other medicines, to treat high blood pressure.
How It Works
Terazosin is an alpha-1 blocker. It relaxes the smooth muscle in the prostate and the neck of the bladder, making it easier to pass urine. It also relaxes blood vessels, which lowers blood pressure.
Dosage and Administration
Treatment starts with 1 mg at bedtime to reduce dizziness from a sudden fall in blood pressure. The dose is then increased slowly by the doctor, often to 2 mg, 5 mg or 10 mg once a day for BPH, and 1 mg to 5 mg (up to 20 mg) a day for high blood pressure. If you miss several days, restart at 1 mg and ask your doctor. Take it at the same time each day, with or without food.
Interactions
- Other blood pressure medicines, diuretics and other alpha blockers: greater fall in blood pressure.
- Sildenafil, Tadalafil, Vardenafil, Avanafil and similar ED medicines: risk of low blood pressure and fainting.
- Alcohol: increases dizziness.
- Verapamil: may increase Terazosin levels and effect.
Contraindications
- Allergy to Terazosin or similar medicines (Prazosin, Doxazosin).
- History of fainting when passing urine (micturition syncope).
Side Effects
Common side effects include dizziness, light-headedness when standing, tiredness, weakness, headache, stuffy nose, swollen ankles, palpitations and blurred vision. Fainting can happen, especially after the first dose or a dose increase.
Get urgent medical help if you faint, have chest pain, a very fast or irregular heartbeat, a painful erection lasting more than 4 hours, or signs of a severe allergic reaction such as swelling of the face or throat or difficulty breathing.
Pregnancy and Lactation
Terazosin is mainly used in men. If needed in pregnancy for high blood pressure, it should only be used if a doctor decides the benefit outweighs the risk. It is not known whether it passes into breast milk; ask your doctor before use while breastfeeding.
Precautions and Warnings
Stand up slowly, especially after the first dose; sit or lie down if you feel dizzy. Avoid driving or dangerous tasks for 12 hours after the first dose or a dose change. Tell your eye surgeon you take it before cataract surgery (risk of floppy iris syndrome). Prostate cancer should be ruled out before treating BPH.
Overdose
An overdose may cause very low blood pressure, severe dizziness, fainting and a fast heartbeat. Lie the person down with legs raised and seek emergency medical help.
Therapeutic Class
Alpha-1 adrenergic blocker; drug for BPH and antihypertensive.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.