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Generic Name: silodosin (SIL oh DOE sin)
Brand Name: Rapaflo

What is silodosin?

Silodosin is an alpha-adrenergic (AL-fa ad-ren-ER-jik) blocker. Silodosin helps relax the muscles in the prostate and bladder neck, making it easier to urinate.

Silodosin is used to improve urination in men with benign prostatic hyperplasia (enlarged prostate).

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

What is the most important information I should know about silodosin?

You should not take silodosin if you have severe kidney or liver disease.

Do not take silodosin together with similar medicines such as alfuzosin, doxazosin, prazosin, tamsulosin, or terazosin.

There are many other drugs that can interact with silodosin. Tell your doctor about all medications you use.

What should I discuss with my healthcare provider before taking silodosin?

You should not take silodosin if you are allergic to it, or if you have:

  • severe liver disease; or

  • severe kidney disease.

Some medicines can interact with silodosin and should not be used at the same time. Your doctor may need to change your treatment plan if you use any of the following drugs:

  • imatinib;

  • isoniazid;

  • nefazodone;

  • an antibiotic--clarithromycin, telithromycin;

  • antifungal medicine--itraconazole, ketoconazole, posaconazole, voriconazole;

  • heart medication--nicardipine, quinidine;

  • antiviral medicine to treat hepatitis C or HIV/AIDS--atazanavir, boceprevir, cobicistat, delavirdine, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir, telaprevir; or

  • medicines similar to silodosin--alfuzosin, doxazosin, prazosin, tamsulosin, or terazosin.

To make sure silodosin is safe for you, tell your doctor if you have:

  • low blood pressure;

  • kidney disease (or if you are on dialysis);

  • heart disease;

  • a history of prostate cancer;

  • a condition for which you take a diuretic or "water pill"; or

  • if you are on a low-salt diet.

Silodosin can affect your pupils during cataract surgery. Tell your eye surgeon ahead of time that you are using this medicine.

Although silodosin is not for use in women, this medicine is not expected to harm an unborn baby or a nursing baby. If you are a woman and you take silodosin, tell your doctor if you are pregnant or breast-feeding.

Silodosin is not approved for use by anyone younger than 18 years old.

How should I take silodosin?

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Silodosin is usually taken once daily with a meal. Follow your doctor's dosing instructions very carefully.

Silodosin lowers blood pressure and may cause dizziness or fainting, especially when you first start taking it. You may feel very dizzy when you first wake up. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

While using silodosin, your blood pressure and prostate will need to be checked often.

Some things can cause your blood pressure to get too low. This includes vomiting, diarrhea, or heavy sweating. Call your doctor if you have a prolonged illness that causes diarrhea or vomiting.

Store at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking silodosin?

This medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Drinking alcohol with this medicine can cause side effects.

Silodosin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • severe dizziness, or if you feel like you might pass out.

Common side effects may include:

  • dizziness;

  • headache;

  • diarrhea;

  • abnormal ejaculation; or

  • stuffy nose, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect silodosin?

Many drugs can interact with silodosin, and some drugs should not be used together. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all medicines you use, and those you start or stop using during your treatment with silodosin. Give a list of all your medicines to any healthcare provider who treats you.

Where can I get more information?

  • Your pharmacist can provide more information about silodosin.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 3.01.

Date modified: October 14, 2016
Last reviewed: November 18, 2015