Silodosin belongs to a group of medications known as alpha 1A receptor antagonists. It is used to treat symptoms of enlarged prostate (benign prostatic hyperplasia [BPH]).

As the prostate gland enlarges, it can put pressure on the urethra, the tube that carries urine away from the bladder to be expelled. This causes a weak urine stream or a feeling of not being able to empty the bladder completely. Silodosin helps to relax the muscles in the prostate and the opening of the bladder. This helps the stream of urine to flow more freely and the bladder to be emptied completely.

Silodosin does not shrink the prostate gland. Therefore, although symptoms are improved with treatment, prostate surgery may still be needed some time in the future if the prostate gland continues to enlarge.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended dose of silodosin is 8 mg taken once daily, with a meal.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

If you have problems swallowing whole capsules, silodosin capsules may be carefully opened and the powder inside can be sprinkled on a spoonful of applesauce that is either cool or at room temperature. The powder and applesauce mixture should then be swallowed immediately without chewing. Drink a glass of water immediately afterwards, to make sure all the powder has been swallowed.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to silodosin or any ingredients of this medication
• are taking any of the following medications
• clarithromycin
• itraconazole
• ketoconazole
• ritonavir
• other alpha-blockers (e.g., doxazosin, prazosin, terazosin)
• have severely reduced kidney function
• have severely reduced liver function

This medication is not intended to be taken by women or by children under 18 years old.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• diarrhea
• dizziness
• dry cough
• headache
• nasal congestion (stuffy nose)
• reduced or no semen during sexual intercourse
• sore throat

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• dizziness, lightheadedness, or fainting when rising from a sitting or lying position
• fast or pounding heartbeat
• pneumonia that is not caused by infection (e.g., cough, trouble breathing, fever)
• red or purple discolouration of the skin
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of a severe allergic reaction (e.g., hives; difficulty breathing; swelling of the mouth, tongue, face, or throat)
• symptoms of a serious skin reaction (e.g., skin rash, peeling or redness)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Drowsiness/dizziness: This medication may cause dizziness. Do not drive, operate machinery, or perform other hazardous tasks until you have determined how this medication affects you.

Eye surgery: If you are having eye surgery (such as cataract surgery), inform your eye surgeon that you are taking this medication. This type of medication can cause an eye problem during surgery called Intraoperative Floppy Iris Syndrome (IFIS).

Grapefruit and grapefruit juice: Regularly eating grapefruit or drinking grapefruit juice while taking silodosin may cause an increase in the amount of medication in the body, thereby causing an increase in side effects. You should avoid regularly eating or drinking grapefruit products while taking this medication.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have severely reduced kidney function you should not take this medication.

Liver function: Decreased liver function or liver disease may cause this medication to build up in the body, causing side effects. If you have liver disease or reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have severely reduced liver function you should not take this medication.

Orthostatic hypotension: People taking silodosin may experience orthostatic hypotension, which is low blood pressure on rising from a lying or sitting position. If you experience dizziness or weakness, sit or lie down until the symptoms have disappeared. Fainting is the most severe symptom of orthostatic hypotension.

If you experience fainting, contact your doctor as soon as possible. Do not drive or perform hazardous tasks until you are certain that this medication does not impair your ability to perform these tasks safely.

Prostate cancer: Prostate cancer and BPH cause many of the same symptoms. These two diseases frequently coexist. An evaluation should be done to rule out prostate cancer before silodosin therapy is started. Silodosin is not intended to treat symptoms of prostate cancer.

Pregnancy: This medication is not intended for use by women, including those who are or may be pregnant.

Breast-feeding: Silodosin is not intended for use by women, including those who are breast-feeding.

Children: This medication is not intended for use by children. The safety and effectiveness of silodosin have not been established for use by people in this age group.

Seniors: It is likely that people over the age of 65 will experience more side effects, such as dizziness, and should report any unusual effects to their doctor as soon as possible.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.