Doxazosin is used to treat enlarged prostate. It does not shrink the prostate. Works by relaxing bladder and prostate muscles to allow urine to flow easily. It also can treat high blood pressure.
Doxazosin is a prescription medication used to treat high blood pressure and the symptoms of enlarged prostate. Doxazosin belongs to a group of drugs called alpha-blockers. It lowers blood pressure by relaxing veins and arteries so that blood can more easily pass through them. Doxazosin also relieves the symptoms of enlarged prostate by relaxing the muscles of the bladder and prostate.
This medication comes in tablet form and is taken once a day, with or without food.
It also comes in an extended-release tablet form and is taken once a day in the morning with breakfast. Do not chew, divide, cut, or crush extended-release tablets.
Common side effects of doxazosin include dizziness, fatigue, and drowsiness. Do not drive or operate machinery until you know how doxazosin will affect you.
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Doxazosin Cautionary Labels
Uses of Doxazosin
Doxazosin is a prescription medication used to treat high blood pressure (hypertension).
Doxazosin is also used to improve urination in men with benign prostatic hyperplasia (BPH). Symptoms include:
- difficulty starting a urine stream (hesitancy and straining)
- decreased strength of the urine stream (weak flow)
- dribbling after urination
- feeling that the bladder is not completely empty
- an urge to urinate again soon after urinating
- waking at night to urinate
- frequent urination
- a sudden, uncontrollable urge to urinate
- burning or pain during urination
This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.
Doxazosin Brand Names
Doxazosin may be found in some form under the following brand names:
Doxazosin Drug Class
Doxazosin is part of the drug class:
Side Effects of Doxazosin
Serious side effects have been reported. See "Drug Precautions" section.
Common side effects include:
- swelling of feet or hands
- difficulty breathing
- low blood pressure
- abnormal vision
- runny nose
- decreased sexual ability
This is not a complete list of doxazosin side effects. Ask your doctor or pharmacist for more information.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:
- avanafil (Stendra)
- cimetidine (Tagamet)
- sildenafil (Viagra, Revatio)
- tadalafil (Cialis, Adcirca)
- vardenafil (Levitra, Staxyn)
This is not a complete list of doxazosin drug interactions. Ask your doctor or pharmacist for more information.
Serious side effects have been reported including:
- Extremely rarely, doxazosin and similar medications have caused painful erection of the penis, sustained for hours and unrelieved by sexual intercourse or masturbation. This condition, known medically as priapism, is serious, and if untreated it can be followed by permanent inability to have an erection. If you have a prolonged abnormal erection, call your doctor or go to an emergency room as soon as possible.
- If you plan to have surgery for cataracts (clouding of the eye), tell your surgeon if you take or have taken doxazosin. During cataract surgery, a condition called Intraoperative Floppy Iris Syndrome (IFIS) can happen if you take or have taken doxazosin.
- Doxazosin lowers blood pressure and may cause dizziness or fainting, especially when you first start taking it, or when you start taking it again. Call your doctor if you have severe dizziness or feel like you might pass out.
Doxazosin can cause drowsiness. Do not drive or operate heavy machinery until you know how doxazosin affects you.
Do not take doxazosin if you:
- are allergic to doxazosin or any inactive ingredient in this medication
- are allergic to any of the medications related to doxazosin such as alfuzosin (Uroxatral), prazosin (Minipress), and terazosin (Hytrin)
Doxazosin Food Interactions
Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of doxazosin, there are no specific foods that you must exclude from your diet when receiving this medication.
Before taking doxazosin, tell your doctor about all of your medical conditions. Especially tell your doctor if you:
- are allergic to doxazosin or any inactive ingredient in doxazosin
- have or have ever had prostate cancer
- have or have ever had liver disease
- are pregnant or breastfeeding
Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.
Doxazosin and Pregnancy
Tell your doctor if you are pregnant or plan to become pregnant.
The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.
Doxazosin falls into category C. There are no good studies in pregnant women. Doxazosin should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.
Doxazosin and Lactation
Tell your doctor if you are breastfeeding or planning to breastfeed.
It is not known whether doxazosin crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using doxazosin.
- Take doxazosin exactly as prescribed.
- Doxazosin comes in tablet form and is usually taken once daily, at around the same time each day. This medication can be taken with or without food.
- Doxazosin also comes in an extended-release tablet form and is taken once a day in the morning, with breakfast. Do not chew, divide, cut, or crush extended-release tablets.
- If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of doxazosin at the same time.
Take doxazosin exactly as prescribed. Follow the directions on your prescription label carefully.
Doxazosin immediate-release tablet
The recommended starting dose for doxazosin (Cardura) is 1 mg. The dose is gradually increased to manage side effects. The maximum dose for enlarged prostate is 8 mg per day. The maximum dose for the treatment of hypertension is 16 mg per day.
Doxazosin extended-release tablets
The recommended starting dose of doxazosin extended-release tablets (Cardura XL) is 4 mg once daily, in the morning with breakfast.
The dose can be gradually increased based on how you respond and tolerate your medication. The maximum dose of doxazosin extended-release tablets (Cardura XL) for the treatment of enlarged prostate is 8 mg per day.
If your medication is discontinued for several days, therapy should be restarted using the 4 mg once daily dose.
If you take too much of this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.
If this medication is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention
- Store tablets at 25°C (77°F).
- Store away from moisture and heat.
- Keep this and all medications out of the reach of children.