Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page: https://medlineplus.gov/druginfo/meds/a609002.html

Silodosin

pronounced as (sye'' lo doe' sin)

Why is this medication prescribed?

Silodosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia; BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Silodosin is in a class of medications called alpha-blockers. It relieves the symptoms of BPH by relaxing the muscles of the bladder and prostate.

How should this medicine be used?

Silodosin comes as a capsule to take by mouth. It is usually taken with food once a day. Do not take silodosin on an empty stomach. Take silodosin at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take silodosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Silodosin controls the symptoms of BPH but does not cure it. Continue to take silodosin even if you feel well. Do not stop taking silodosin without talking to your doctor.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking silodosin,

  • tell your doctor and pharmacist if you are allergic to silodosin or any other medications.
  • tell your doctor if you are taking antifungals such as ketoconazole (Nizoral) and itraconazole (Sporanox); clarithromycin (Biaxin, in Prevpac); HIV protease inhibitors such as indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Fortovase); nefazodone; telithromycin (Ketek). Your doctor will probably tell you not to take silodosin.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: cyclosporine (Neoral, Sandimmune); diltiazem (Cardizem, Dilacor, Tiazac); erythromycin (E.E.S., E-Mycin, Erythrocin); fluconazole (Diflucan); medications for high blood pressure;other alpha blockers such as doxazosin (Cardura), prazosin (Minipress), terazosin (Hytrin), and tamsulosin (Flomax); and verapamil (Calan, Covera, Isoptin, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with silodosin, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor if you have kidney or liver disease. Your doctor will probably tell you not to take silodosin.
  • tell your doctor if you have or have ever had low blood pressure.
  • you should know that silodosin is only for use in men. Women should not take silodosin, especially if they are or could become pregnant or are breast-feeding. If a pregnant woman takes silodosin, she should call her doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking silodosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken silodosin.
  • you should know that silodosin may make you drowsy or dizzy, especially when you first start taking it. Do not drive a car or operate machinery until you know how this medication affects you.
  • you should know that silodosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking silodosin. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. If these symptoms do not improve, call your doctor.

What special dietary instructions should I follow?

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine.

What should I do if I forget a dose?

Take the missed dose with a meal as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Silodosin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • orgasm with little or no semen (fluid)
  • diarrhea
  • dizziness
  • low blood pressure
  • stuffy or runny nose

Some side effects can be serious. If you experience any of these symptoms , call your doctor immediately:

  • painful erection of the penis that lasts for several hours

Silodosin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

  • dizziness
  • fainting
  • lightheadedness
  • blurred vision

What other information should I know?

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand names

  • Rapaflo®
Last Revised - 10/15/2016