Doxazosin is in a group of drugs called alpha-adrenergic blockers. Doxazosin 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).

Doxazosin may also be used for other purposes not listed in this medication guide.

Doxazosin can affect your pupils during cataract surgery. Tell your eye surgeon ahead of time that you are using doxazosin. Do not stop using this medicine before surgery unless your surgeon tells you to.

You should not use this medication 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.