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Silodosin, Oral Capsule

Highlights for silodosin

  1. Silodosin oral capsule is available as a brand-name drug and a generic drug. Brand name: Rapaflo.
  2. Silodosin comes only as a capsule you take by mouth.
  3. Silodosin is used in adult men to treat benign prostatic hyperplasia (BPH). It helps lessen your BPH symptoms and improve your ability to urinate.
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Important warnings

Important warnings

  • Fainting and dizziness warning: This drug may cause low blood pressure when you stand up after sitting or lying down, which may lead to dizziness and fainting. Don’t drive, use machinery, or perform dangerous tasks until you know how it affects you.
  • Cataract surgery warning: This drug may affect your pupils during cataract surgery. A complication known as intraoperative floppy iris syndrome (IFIS) has occurred in some people who were taking or recently took this type of drug.

About

What is silodosin?

Silodosinis a prescription medication. It comes as an oral capsule.

Silodosin oral capsule is available as the brand-name drug Rapaflo. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in every strength or form as the brand-name drug.

Silodosin may be used as part of a combination therapy. That means you need to take it with other drugs.

Why it's used

Silodosinis used to treat the symptoms of benign prostatic hyperplasia (BPH) in men with an enlarged prostate.

When the prostate is enlarged, it can pinch or squeeze your urethra and affect your ability to urinate. This may cause:

  • nighttime urination (nocturia)
  • sudden urge to urinate
  • frequent urge to urinate
  • difficulties in starting to urinate
  • feeling like you can’t completely empty your bladder
  • weak urine flow
  • straining while urinating
  • dribbling (leaking) after urination

How it works

This drug belongs to a class of drugs called alpha-1 blockers. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Alpha-1 receptors are located in your prostate and bladder. They’re responsible for the contraction of the smooth muscles of the bladder and prostate. Silodosin blocks these receptors, which causes the smooth muscles in the prostate and bladder to relax. This will reduce your BPH symptoms and improve your ability to urinate.

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Side effects

Silodosin side effects

Silodosin oral capsule doesn’t cause drowsiness, but it can cause other side effects.

More common side effects

The more common side effects that occur with silodosin include:

  • dizziness
  • diarrhea
  • low blood pressure when you stand up after sitting or lying down (orthostatic hypotension)
  • headache
  • retrograde ejaculation (occurs when semen enters the bladder instead of out the tip of the penis)
  • common cold
  • stuffy nose

Mild side effects may disappear within a few days or a couple of weeks. Talk to your doctor or pharmacist if they’re more severe or don’t go away.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Allergic (drug hypersensitivity) reaction. Symptoms may include:
    • swelling of your face, lips, tongue, or throat
    • problems with breathing or swallowing
    • skin rash
    • itching
    • hives
    • blisters on your skin or in your mouth, nose, or eyes
    • peeling skin
    • fainting or feeling dizzy
    • very rapid heartbeat
  • Liver problems. Symptoms may include:
    • yellowing of your skin or the whites of your eyes
    • nausea
    • vomiting
    • loss of appetite
    • stomach pain and swelling
    • bruising easily
    • pale stool color
    • dark urine
    • unusual or unexplained tiredness
  • Prolonged erection (priapism). This is an erection that lasts longer than 4 hours.
  • Sudden drop in blood pressure, especially when you stand up after sitting or lying down. Symptoms may include:
    • dizziness
    • feeling lightheaded
    • fainting

    Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we can not guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Interactions

Silodosin may interact with other medications

Silodosin oral capsule can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with silodosin are listed below.

Antifungals

Taking these drugs with silodosin can increase the levels of silodosin in your body. Do not take these drugs with silodosin:

  • itraconazole (Sporanox)
  • ketoconazole (Nizoral)

Taking this drug with silodosin may increase the levels of silodosin in your body:

  • posaconazole (Noxafil)

Blood pressure drugs

Taking calcium channel blockers with silodosin may increase the levels of silodosin in your body. Examples of these drugs include:

  • diltiazem (Cardizem)
  • verapamil (Calan)

Taking any blood pressure medications with silodosin can increase your risk of low blood pressure, a sudden drop in your blood pressure when getting up after sitting or lying down, or fainting.

Antibiotics

Taking clarithromycin (Biaxin) with silodosin increases the levels of silodosin in your body. Do not take this drug with silodosin.

Taking erythromycin with silodosin may increase the levels of silodosin in your body.

Human immunodeficiency virus (HIV) medications

These belong to a drug class called protease inhibitors. Taking these medications with silodosin may increase the levels of silodosin in your body. Examples of these drugs include:

  • atazanavir (Reyataz)
  • darunavir (Prezista, Prezcobix)
  • elvitegravir/cobicistat/emtricitabine/tenofovir (Stribild)
  • fosamprenavir (Lexiva)
  • lopinavir/ritonavir (Kaletra)
  • indinavir (Crixivan)
  • nelfinavir (Viracept)
  • saquinavir (Invirase)

Taking ritonavir (Norvir) with silodosin increases the levels of silodosin in your body. Do not take this drug with silodosin.

Immune-suppressing drug

Taking cyclosporine with silodosin may increase the levels of silodosin in your body.

Hepatitis C drug

Taking boceprevir (Victrelis) with silodosin may increase the levels of silodosin in your body.

Other drugs used to treat benign prostatic hyperplasia (BPH)

These medications may cause your blood pressure to become too low if taken with silodosin. They may also increase your risk of orthostatic hypotension, which isa sudden drop in blood pressure when getting up after sitting or lying down. This condition can cause dizziness or fainting.

Examples of these drugs include:

  • alfuzosin (Uroxatral)
  • doxazosin (Cardura)
  • prazosin (Minipress)
  • terazosin
  • tamsulosin (Flomax)

Blood pressure drugs

These medications may cause your blood pressure to become too low if taken with silodosin. They may also increase your risk of orthostatic hypotension, which is a sudden drop in blood pressure when getting up after sitting or lying down. This condition can cause dizziness or fainting.

Examples of these drugs include:

  • metoprolol
  • carvedilol
  • atenolol
  • lisinopril
  • losartan
  • valsartan
  • amlodipine
  • clonidine

Erectile dysfunction drugs

These medications may cause your blood pressure to become too low if taken with silodosin. They may also increase your risk of orthostatic hypotension, which is a sudden drop in blood pressure when getting up after sitting or lying down. This condition can cause dizziness or fainting.

Examples of these drugs include:

  • avanafil (Stendra)
  • sildenafil (Viagra)
  • tadalafil (Cialis)
  • vardenafil (Levitra)

Pulmonary hypertension drug

Taking sildenafil (Revatio) with silodosin may cause your blood pressure to become too low. It may also increase your risk of orthostatic hypotension, which is a sudden drop in blood pressure when getting up after sitting or lying down. This condition can cause dizziness or fainting.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we can not guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

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Other warnings

Silodosin warnings

This drug comes with several warnings.

Allergy warning

This drug can cause a severe allergic reaction. Symptoms may include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives
  • itching
  • rash

Call 911 or go to the nearest emergency room if you develop these symptoms.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Grapefruit warning

If you drink grapefruit juice while taking silodosin, it may increase the levels of silodosin in your body and possibly cause increased side effects. Talk to your doctor about whether grapefruit products are safe for you.

Alcohol interaction warning

Silodosin can make you dizzy. Consuming alcohol may also make you dizzy and drowsy. You should limit the amount of alcohol you drink.

Warnings for people with certain health conditions

For people with kidney disease: Your body gets rid of this drug partly through your kidneys. If your kidneys aren’t working well, more of the drug may stay in your body. This increases your risk of side effects. This drug isn’t recommended if you have severe kidney disease. If you have moderate kidney disease, your doctor may give you a lower dosage.

For people with liver disease: This drug is processed by your liver. If your liver isn’t working well, more of the drug may stay in your body. This increases your risk of side effects. This drug isn’t recommended if you have severe liver disease, because it hasn’t been studied in people with this condition.

For people with low pressure (hypotension): This drug may cause low blood pressure when you stand up after sitting or lying down, dizziness, and even further lowering of your blood pressure. Don’t drive, use machinery, or perform dangerous tasks until you know how it affects you.

Warnings for other groups

For pregnant women: This drug is used to treat BPH in men. It isn’t intended for women.

This drug is a pregnancy category B drug. That means two things:

  1. Studies of the drug in pregnant animals haven’t shown risk to the fetus.
  2. There aren’t enough studies done in pregnant women to show the drug poses a risk to the fetus.

For women who are breastfeeding: This drug is used to treat BPH in men. It isn’t intended for women. It isn’t known if this drug passes through breast milk.

For seniors: If you’re 65 years or older, you may be at higher risk for low blood pressure when you stand up from sitting or lying down (orthostatic hypotension).

For children: It isn’t known if this drug is safe and effective in children younger than 18 years old. It isn’t recommended for use in children.

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Dosage

How to take silodosin

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Drug forms and strengths

Generic: Silodosin

  • Form: oral capsule
  • Strengths: 4 mg and 8 mg

Brand: Rapaflo

  • Form: oral capsule
  • Strengths: 4 mg and 8 mg

Dosage for benign prostatic hyperplasia

Adult dosage (ages 18–64 years)

The typical dosage is 8 mg taken once per day with a meal.

Child dosage (ages 0–17 years)

The safety and effectiveness of silodosin in children haven’t been established. Silodosin isn’t recommended for children younger than 18 years.

Senior dosage (ages 65 years and older)

As you age, your organs (such as liver or kidneys) may not work as well. Your body may process this drug more slowly. Too much drug in your body can lead to more side effects. Based on how well your liver and kidneys are working, your doctor may decide to adjust your dosage, or not prescribe this drug at all.

Special dosage considerations

For people with kidney disease: Dosing for silodosin depends on your kidney function.

  • Severe kidney disease: Silodosin isn’t recommended.
  • Moderate kidney disease: The dosage may be 4 mg taken once per day with a meal.
  • Mild kidney disease: The dosage may be 8 mg taken once per day with a meal.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we can not guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

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Take as directed

Take as directed

Silodosin is used for long-term treatment. It comes with serious risks if you don’t take it as prescribed.

If you don’t take it at all or stop taking it: If you don’t take or stop taking this drug, you may have increased symptoms of BPH. If you stop or forget to take this medication for several days, talk with your doctor before starting again.

If you take too much: You may experience low blood pressure, especially when you stand up after sitting or lying down. Symptoms may include:

  • feeling dizzy or lightheaded
  • fainting
  • weakness
  • blurry vision
  • confusion

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: If you miss a dose, take it as soon as you can. However, if it’s just a few hours until your next dose, skip the missed dose. Never try to catch up by taking two capsules at once. This could result in dangerous side effects.

How to tell if the drug is working: Your BPH symptoms should improve. You may have an easier time urinating.

Important considerations

Important considerations for taking silodosin

Keep these considerations in mind if your doctor prescribes silodosin for you.

General

  • This drug should be taken with a meal.
  • Taking this drug on an empty stomach may increase your risk for side effects, such as a drop in blood pressure when rising after sitting or lying down.
  • Take this drug at the same time every day. This may help to reduce side effects.
  • If you have trouble swallowing capsules, you can open the capsule carefully and sprinkle the powder inside onto a tablespoonful of applesauce. Swallow the applesauce within 5 minutes without chewing. Drink an 8-ounce glass of cool water to make sure you completely swallowed the powder. The applesauce shouldn’t be hot and it should be soft enough to be swallowed without chewing. Don’t store any of this powder/applesauce mixture for future use.

Storage

  • Store silodosin in temperatures from 59°F to 86°F (15°C to 30°C).
  • Keep it away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

During your treatment with silodosin, your doctor may do certain tests. These tests may include:

  • Prostate-specific antigen blood test: The symptoms of BPH and prostate cancer may be similar. Your doctor may perform an exam and a blood test called a prostate specific antigen (PSA) to make sure you don’t have prostate cancer before prescribing this drug.
  • Blood pressure check: You doctor may check to see if your blood pressure is low. If you have low blood pressure (hypotension), taking this drug may lower your blood pressure even more and may not be safe for you to take.

Your diet

To help reduce the symptoms of BPH, your doctor may instruct you to limit the amount of fluid you drink at night. They may also recommend that you reduce the amount of alcohol and caffeine you drink.

Availability

Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead to make sure your pharmacies carries it.

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

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Alternatives

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained here in is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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