Silodosin (Rapaflo) is used to treat symptoms of benign prostatic hyperplasia (BPH), or having an enlarged prostate. This medication is available as a brand-name and generic version, and it comes as a capsule that you take by mouth. The dosage is typically just once daily with a meal, but it can affect your ejaculation as a side effect (for example, causing you to orgasm with less or no semen).
Silodosin (Rapaflo) is an alpha-1 blocker. It specifically blocks the alpha-1 receptor (protein) located on your prostate and bladder. This helps relax those muscles and make it easier for you to urinate.
Source:Â DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Less common
Chills
cold sweats
confusion
dizziness
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Change or problem with discharge of semen
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Helps improve symptoms of BPH
Once-daily dosing
Can open capsules and sprinkle the powder inside on applesauce if it's hard to swallow the capsules whole
Lower-cost generic version available
Has some side effects related to low blood pressure, such as dizziness
Can cause retrograde ejaculation (an orgasm with little or no semen), but is reversible when you stop the medication
Might complicate cataract surgery
Can't use if you have severe kidney or liver problems
Take silodosin (Rapaflo) with a meal. Taking the medication on an empty stomach might lead to more side effects.
If you have a hard time swallowing the capsule, you can open it up and sprinkle the powder inside onto a tablespoon of applesauce (cool or room temperature). Once sprinkled, swallow the spoonful right away without chewing. Then, drink a full glass of water to make sure you've swallowed all of the medication.
You might feel dizzy or lightheaded while you're taking silodosin (Rapaflo), especially when you stand from a lying down or sitting position. This can be dangerous if the dizziness causes you to fall. When you stand up, try to hold onto something like a sturdy table to help support your weight. Don't stand up too quickly.
Avoid drinking alcohol with silodosin (Rapaflo). Both alcohol and silodosin (Rapaflo) can make you dizzy, which could possibly lead to falls.
Avoid driving, using heavy machinery, or doing other activities that require a lot of coordination when you first start silodosin (Rapaflo). This medication can cause side effects like dizziness that make these activities more difficult or dangerous so it's best to wait until you know how it affects your body first.
Make sure you talk to your provider about all the medications you're taking. Your provider can check to see whether there are drug interactions with silodosin (Rapaflo) that can raise your risk of harm. If there are, your provider might need to change the doses of your medications to make sure you're getting the right amount of everything you're prescribed.
Silodosin (Rapaflo) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Have low blood pressure | Taking blood pressure medications | Taking PDE5 inhibitors
Silodosin (Rapaflo) makes your blood pressure drop when you go from sitting to standing. Sometimes, this can cause dizziness or fainting. This blood pressure drop is usually worse when you first start taking silodosin (Rapaflo). Your risk might be higher if you're taking blood pressure medications or PDE5 inhibitors like sildenafil. Avoid driving or using heavy machinery until you know how this medication makes you feel.
You might be at higher risk of side effects from silodosin (Rapaflo) if you have kidney problems. When your kidneys don't work as well as they should, your body can't get rid of the medication from your system as well. As a result, the medication can build up in your body and raise your risk for toxicity. Let your provider know before starting silodosin (Rapaflo) if you have kidney problems. Your provider might recommend a low dose for you to lower your risk for side effects. Tell your provider if you experience any side effects while taking silodosin (Rapaflo). You can't take silodosin (Rapaflo) and will need to take a different medication if you have severe kidney problems.
Silodosin (Rapaflo) interacts with a number of medications. Some medications, like ketoconazole, clarithromycin, and ritonavir, can slow down the breakdown of silodosin (Rapaflo) and cause its levels to go too high in your body. Other medications have similar side effects as silodosin (Rapaflo). For example, be careful if you're also taking PDE5 inhibitors like sildenafil; both silodosin (Rapaflo) and PDE5 inhibitors can lower your blood pressure. Make sure you talk to your providers and pharmacists about all the medications you're taking. They might need to change the doses of the medications you're taking to keep you safe.
Many of the symptoms of prostate cancer and enlarged prostate overlap. Your healthcare provider will examine you for prostate cancer to rule it out before treating you for BPH with silodosin (Rapaflo).
Risk factors: Cataracts surgery
Tell your eye provider if you are or have ever taken silodosin (Rapaflo) in the past. Although rare, some people have experienced a rare eye condition during cataract surgery called floppy iris syndrome (FIS). FIS can raise your risk of having eye problems during and after cataract surgery, and it can happen even after you've stopped taking silodosin (Rapaflo). Let your eye provider know if you're taking silodosin (Rapaflo) so they're aware of your risk for FIS.
The typical dose is 8 mg by mouth once daily with a meal.
Your dose might differ if you have kidney problems.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Severe kidney problems
Severe liver problems
Take certain medications (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir)
Enlarged prostate (benign prostatic hyperplasia, BPH)
Relieves urinary symptoms
Lessens the need for prostate surgery
By providing your email, you consent to receive marketing communications from GoodRx, which may include content and/or data related to men’s health, women's health, reproductive care, or sexual health. You agree to the GoodRx Terms of Use and acknowledge the Privacy Policy. You can unsubscribe at any time.
Alembic Pharmaceuticals Limited. (2023). Silodosin capsule [package insert]. DailyMed.
Capogrosso, P., et al. (2015). Effects of silodosin on sexual function - Realistic picture from the everyday clinical practice. Andrology.
Flach, A. J. (2009). Intraoperative floppy iris syndrome: Pathophysiology, prevention, and treatment. Transactions of the American Ophthalmological Society.
Jung, J. H., et al. (2017). Silodosin for the treatment of lower urinary tract symptoms in men with benign prostatic hyperplasia. The Cochrane Database of Systematic Reviews.
National Cancer Institute. (n.d.). Understanding prostate changes: A health guide for men.
National Institute of Diabetes and Digestive and Kidney Diseases. (2014). Prostate enlargement (benign prostatic hyperplasia).
Sandhu, J. S., et al. (2023). Management of lower urinary tract symptoms attributed to benign prostatic hyperplasia: AUA guideline. Journal of Urology.
Semet, M., et al. (2017). The impact of drugs on male fertility: A review. Andrology.
Sertkaya, Z., et al. (2019). Silodosin has nocebo effect on sexual adverse effects: A randomized controlled trial. The Eurasian Journal of Medicine.
Villa, L., et al. (2019). Silodosin: An update on efficacy, safety and clinical indications in urology. Advances in Therapy.
Yoshida, M., et al. (2011). Safety and efficacy of silodosin for the treatment of benign prostatic hyperplasia. Clinical Interventions in Aging.
Research prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.