Common use

Doxazosin is an alpha-adrenergic (AL-fa ad-ren-ER-jik) blockers. It relaxes your veins and arteries so that blood can more easily pass through them. It also relaxes the muscles in the prostate and bladder neck, making it easier to urinate. Doxazosin is used to treat hypertension (high blood pressure), or to improve urination in men with benign prostatic hyperplasia (enlarged prostate). The extended-release form of doxazosin is for use only in treating benign prostatic hyperplasia and should not be used to treat hypertension.

Dosage and direction

Take doxazosin exactly as prescribed by your doctor. Do not use this medicine in larger or smaller amounts or for longer than recommended. While using doxazosin, your blood pressure or prostate may need to be checked often.
If you are being treated for high blood pressure, keep using this medicine even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medicine for the rest of your life.

Precautions

To make sure doxazosin is safe for you, tell your doctor if you have: a blockage in your digestive tract (stomach or intestines); severe constipation; liver disease; or low blood pressure.
Doxazosin can affect your pupils during cataract surgery. Tell your eye surgeon ahead of time that you are using this medication. Do not stop using this medicine before surgery unless your surgeon tells you to.
It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.
It is not known whether doxazosin passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Contraindications

You should not use this medicine if you are allergic to doxazosin or similar medicines such as alfuzosin (Uroxatral), prazosin (Minipress), silodosin (Rapaflo), tamsulosin (Flomax), or terazosin (Hytrin).
Doxazosin may cause dizziness or fainting, especially when you first start taking it or when you start taking it again. Be careful if you drive or do anything that requires you to be alert. Avoid standing for long periods of time or becoming overheated during exercise and in hot weather. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.
Drinking alcohol with this medicine can cause side effects.

Possible side effect

Get emergency medical help if you have signs of an allergic reaction to doxazosin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have: a light-headed feeling, like you might pass out; severe ongoing stomach pain or bloating; new or worsening chest pain; trouble breathing; or a penis erection that is painful or lasts 4 hours or longer.
Common doxazosin side effects may include: low blood pressure, dizziness; drowsiness; headache; or feeling weak or tired.

Drug interaction

Tell your doctor about all other medications you use, especially other blood pressure medications including diuretics (water pills). Tell your doctor about all your current medicines and any you start or stop using, especially: an antibiotic; an antidepressant; medicine to treat HIV or AIDS; or sildenafil (Viagra) or other erectile dysfunction medicines.

Missed dose

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose. If you miss your doses for several days in a row, call your doctor before restarting the medication. You may need a lower dose.

Overdose

Overdose symptoms may include extreme dizziness or fainting. Seek emergency medical attention.

Storage

Store at room temperature away from moisture and heat. Keep away from children and pets.