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Generic Name: Doxazosin [dox-AY-zo-sin]
Brand Names: Cardura, Cardura XL, Doxadura, Cascor, Carduran
Classification of the Drugs Beta-adrenoreceptor antagonists are antiadrenergic agents that are peripherally acting.

What is Doxazosin?

Doxazosin is one of the alpha-adrenergic (AL-fa Ad-ren-ER-jik) blockers. It relaxes your veins as well as your arteries, allowing blood to flow more easily through them. It also relaxes the muscles of the prostate and bladder neck, which makes it easier to urinate.

Doxazosin helps treat hypertension (high blood pressure) as well as improve the urination rate of men suffering from benign prostatic hyperplasia (enlarged prostate).The extended-release Doxazosin (Cardura XL) is for use exclusively to treat benign prostatic hyperplasia. The drug should not be utilized in the treatment of hypertension.


Doxazosin can affect your pupils during cataract surgery. Inform your eye surgeon prior to surgery that you're using Doxazosin. Do not stop taking this medication prior to surgery unless your doctor tells you otherwise.

It is not recommended to use this medication if you are sensitive to doxazosin or similar medications like alfuzosin (Uroxatral), prazosin (Minipress), silodosin (Rapaflo), tamsulosin (Flomax), or terazosin (Hytrin). Doxazosin could cause dizziness and fainting, particularly at the beginning of your treatment with it or when you begin taking it regularly. Be aware when you drive or do any other activity that requires you to be alert. Avoid standing for prolonged durations or becoming hot during exercise or in hot temperatures. Be careful not to get up too quickly from a lying or sitting position. You may be dizzy.

Inform your doctor about any other medications you are taking, including blood pressure medications such as diuretics (water pills).

Before you Take this Drug

It is not recommended to use this medication if you have an allergy to doxazosin or similar medications like alfuzosin (Uroxatral) or prazosin (Minipress), silodosin (Rapaflo), tamsulosin (Flomax), and terazosin (Hytrin).

To ensure doxazosin's suitability for you, inform your physician if you suffer from:

  • A blockage within your digestive tract (stomach and intestines);
  • Severe constipation;
  • Liver disease
  • Lower blood pressure.

Doxazosin can affect your pupils during cataract surgery. Inform your eye surgeon in advance that you're using this drug. Don't stop using this medication prior to surgery unless your doctor tells you to.

It is unclear if this medicine could cause harm to a baby who is not yet born. Inform your doctor if you are expecting or planning to be pregnant.It isn't known if the doxazosin is absorbed into breast milk or if it can harm the baby who is nursing. It is not suggested to breastfeed while taking this medicine.

How to Take Doxazosin?

Follow the exact dosage as recommended by your physician. Follow all the instructions on the prescription label. The doctor may alter your dosage. Don't take this medication in smaller or larger quantities or for a longer time than the recommended time.

Doxazosin decreases blood pressure and can cause fainting or dizziness, especially at the beginning of use or when taking it for the second time.It is possible to feel dizzy the moment you get up. Be aware when standing up or standing up from a lying position.Contact your doctor if you notice severe dizziness or feel as if you're about to faint.

If you're taking doxazosin for treatment, your blood pressure and prostate could require regular checks.When you decide to stop taking the drug doxazosin for any reason, talk to your doctor before using it again. You might require a dose adjustment.

If you're being treated for high blood pressure, you should continue the medication even if you feel good. High blood pressure can have no signs. It is possible that you will need blood pressure medication throughout your life.Place it in a cool, dry place free of heat and moisture.

What Happens if I Miss the Dose?

Take the missed dose the moment you recall. Avoid any missed doses if you are nearing the time for the next dose. Don't take any extra medication to make up for the missed dose.If you have missed your doses for a few days, contact your doctor prior to starting the medication. It is possible that you will need to lower your dosage.

What Happens If I Overdose?

Get medical attention in an emergency or contact the poison help line at 1-800-222-1222.

Overdose symptoms can include severe dizziness or fainting.

What Should be Avoided?

Doxazosin could affect your brain or reactions. Be cautious when driving or doing any activity that requires you to be aware.To prevent dizziness, stay away from sitting for prolonged periods of time or getting too hot during exercise or during hot weather.

Be careful not to get up too quickly from lying or sitting in a position where you could get dizzy. Begin slowly and steady your body to prevent falling.Alcohol consumption with this medicine may cause unwanted side effects.

Side effects of Doxazosin

See a doctor immediately. If you are experiencing symptoms of an allergy reaction to the doxazosin, such as hives, breathing difficulties, or swelling of your lips, face, and throat,

See your doctor right away. If you are suffering from:

  • A feeling of lightheadedness, as if you're about to pass out.
  • Chronic stomach pain that continues to recur or bloating
  • New or worsening chest pain that isn't getting better or worse;
  • Trouble breathing trouble breathing
  • A penis erection that's painful or lasts for four hours or more

Common doxazosin side effects may include:

  • Low blood pressure, dizziness;
  • Drowsiness;
  • Headaches
  • Feeling tired or weak.

This is not a comprehensive list of all the side effects. Other side effects could occur. Consult your physician to seek medical advice on the effects. You can report any adverse reactions to the FDA at 1-800-FDA-1088.

Details on Dosage

Usual Adult Dose for Hypertension:

Initial dose: 1 mg taken orally at least once per day.
Maintenance dose: 1–16 mg once daily.

Usual Adult Dose for Benign Prostatic Hyperplasia:

Initial dose:
In immediate-release form: 1 mg every day, taken orally.
Extended-release: 4 mg taken orally at least once per day for breakfast.
Maintenance dose:
Instant-release: 1–8 mg taken orally every day.
Extended-release: 4–8 mg daily during breakfast. Based on the patient's symptoms, response, and tolerance, the dosage could rise to 8 mg (the maximum dose recommended). The recommended titration period is 3–4 weeks.
If you are switching from tablets with immediate release to extended release tablets, treatment should be started with the smallest dosage (4 mg every day). Before beginning treatment with doxazosin extended-release tablets, the evening's final dose of tablets for immediate release should not be consumed. If the extended-release tablets of doxazosin have been discontinued for a period of time, the therapy should be reintroduced with the 4 mg daily dosage.

Usual Geriatric Dose for Hypertension:

Initial dosage: 0.5 mg orally once per day.

Interaction with Other Drugs

Inform your doctor about all your medications currently in use and any new medications you begin or stop taking, particularly:

  • An antibiotic
  • An antidepressant
  • Medication for treating HIV or AIDS medicine to treat HIV or AIDS
  • Sildenafil (Viagra) or other medicines for erectile dysfunction.

This list isn't complete. Other medications can interact with doxazosin. These include medications that are prescribed and available over the counter, such as vitamins and herbal products. The interactions of all potential types aren't included in this guideline for medication.



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