Health Library

Doxazosin (By mouth)

Doxazosin (dox-AZ-oh-sin)

Treats problems with urination caused by benign prostatic hyperplasia (enlarged prostate). Also treats high blood pressure.

Brand Name(s):

Cardura, Cardura XL

When This Medicine Should Not Be Used:

How to Use This Medicine:

Tablet, Long Acting Tablet

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
• The extended-release tablet should be taken each day with breakfast. The regular-release tablet can be taken in the morning or in the evening.
• Swallow the extended-release tablet whole. Do not crush, break, or chew it.
• If you take the extended-release tablet, part of the tablet may pass into your stools. This is normal and is nothing to worry about.
• Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how doxazosin works. Tell your doctor if you are using any of the following:
  • Atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, or voriconazole
  • Blood pressure medicines
  • Medicine to treat erectile dysfunction

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have liver disease, heart disease, prostate cancer, or stomach or bowel problems (such as a blockage). Tell your doctor if you plan to have cataract surgery.
• This medicine may cause the following problems:
  • New or worsening angina (chest pain)
  • Priapism (painful, prolonged erection)
• This medicine could lower your blood pressure too much, especially when you first use it or if you are dehydrated. This can make you dizzy or lightheaded. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Stand or sit up slowly if you feel lightheaded or dizzy.
• Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Fast, slow, pounding, or uneven heartbeat
• Lightheadedness, dizziness, or fainting
• New or worsening chest pain
• Painful erection or an erection that lasts longer than usual

If you notice these less serious side effects, talk with your doctor:

• Tiredness or weakness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024