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 (Cardura XL) is for use only in treating benign prostatic hyperplasia and should not be used to treat hypertension.
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).
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.
How to take doxazosin
Take doxazosin exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use this medicine in larger or smaller amounts or for longer than recommended.
Doxazosin lowers blood pressure and may cause dizziness or fainting, especially when you first start taking it, or when you start taking it again.
You may feel very dizzy when you first wake up. Be careful when standing or sitting up from a lying position.
Call your doctor if you have severe dizziness or feel like you might pass out.
While using doxazosin, your blood pressure or prostate may need to be checked often.
If you stop taking doxazosin for any reason, ask your doctor before you start taking it again. You may need a dose adjustment.
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.
Store at room temperature away from moisture and heat.
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;
- headache; or
- feeling weak or tired.