5 Silodosin Side Effects You Should Know About
Key takeaways:
Silodosin (Rapaflo) is a medication that treats benign prostatic hyperplasia. Most people don’t have major issues while taking it, but it can cause some side effects.
Common silodosin side effects include ejaculation problems, dizziness, and headaches. Cold symptoms and diarrhea are also possible. Many silodosin side effects go away on their own as your body gets used to the medication.
You can often treat mild side effects at home. But if your symptoms get worse or become severe, let your healthcare team know.
Table of contents
Silodosin (Rapaflo) is a medication taken by mouth that treats symptoms of an enlarged prostate, or benign prostatic hyperplasia (BPH). Several medications treat BPH.
Silodosin is an alpha blocker that helps with BPH symptoms, but it also has some risks.
Your prescriber will likely review certain precautions with you, such as possible side effects, when you first start taking silodosin. Knowing about silodsin’s side effects can help you understand what to expect and when to seek help.
Silodosin side effects at a glance
Like all medications, silodosin can cause certain side effects. Overall, though, it’s considered well tolerated. Most silodosin side effects are mild, and you can often manage them at home. More serious side effects are possible, but they tend to be rare.
Common silodosin side effects include:
Abnormal ejaculation
Dizziness
Diarrhea
Low blood pressure when changing positions (orthostatic hypotension)
Headache
Runny or stuffy nose
Sore throat
Nasal congestion
Rare but serious silodosin side effects include:
Fainting (syncope)
Intraoperative floppy iris syndrome (a complication that can happen during cataract surgery)
An erection that doesn’t go away (priapism)
Below, we’ll cover five notable silodosin side effects in more detail.
What causes BPH? In many cases, getting older can increase your risk of developing benign prostatic hyperplasia (BPH). But it’s not the only cause of the condition.
Compare options. Silodosin is one treatment for BPH. Learn more about the different BPH medications here.
Things to avoid: Several medications can worsen BPH symptoms. Read more about what not to take.
1. Ejaculation problems
The most commonly reported silodosin side effect is ejaculation problems. Typically, this results in less semen ejaculated, or none at all. Evidence doesn’t suggest silodosin causes problems achieving or maintaining an erection. But it’s common to have mild discomfort during ejaculation. This side effect is also common with other alpha blockers, such as tamsulosin (Flomax).
About 25% of people taking silodosin in clinical trials reported ejaculation problems. But further studies have found it may be even more common. It was reported by up to 70% of participants in one study.
Talk to your prescriber if you have any sexual problems while taking this medication. Stopping silodosin seems to fully reverse any ejaculation problems caused by the medication. But don’t stop taking it without your prescriber’s OK.
2. Dizziness
Dizziness is another common silodosin side effect. Similar to ejaculation problems, dizziness is common when taking alpha blockers. This happens because silodosin can lower your blood pressure. You may notice dizziness more when you first start taking the medication.
You may feel dizzy when standing up from a sitting or lying position. This is a symptom of orthostatic hypotension, another possible silodosin side effect. In severe cases, orthostatic hypotension could cause you to fall or faint.
If you feel dizzy while taking silodosin, find a safe place to sit or lie down. And hold onto a sturdy object when standing. Staying well-hydrated can sometimes help limit or prevent dizziness.
When you first start silodosin, avoid driving or performing other tasks that require focus until you know how it affects you. As your body gets used to the medication, dizziness or lightheadedness should go away. If it doesn’t, talk to your healthcare team for further guidance.
3. Diarrhea
Diarrhea is another possible silodosin side effect. If you have mild diarrhea, you can typically manage the symptoms at home until they resolve.
Avoiding fatty or greasy foods and drinking plenty of fluids can help with diarrhea. You can also try following a bland diet for a few days. Over-the-counter (OTC) antidiarrheal medication can be helpful for some people, but make sure it’s OK with your prescriber before taking one.
There are many possible causes of diarrhea. So if you have diarrhea that gets worse or becomes severe, let your healthcare team know. This isn’t a typical silodosin side effect, and there may be another reason for your symptom.
4. Headache
Some people who take silodosin report headaches. These don’t tend to be severe, and they may happen because silodosin can lower your blood pressure. As your body gets used to the medication, headaches caused by it are likely to go away.
If your symptoms don’t go away, you can try staying hydrated, getting extra rest, and exercising. Your prescriber may also recommend an OTC pain reliever for occasional relief. But if your headaches continue to worsen or become severe, let your healthcare team know right away. You may need additional treatment.
5. Cold symptoms
People taking silodosin in clinical trials reported cold symptoms such as a sore throat, congestion, and runny nose. But a similar percentage of people who received a placebo (a pill without medication) reported these symptoms. So it’s unclear whether silodosin actually causes them.
If you have cold symptoms while taking silodosin, there are several ways to treat your symptoms. OTC decongestants and pain relievers can be helpful if your prescriber is OK with you taking them. Keep in mind that your symptoms could be caused by a cold, which should clear up without treatment within 7 to 10 days. But relieving your symptoms in the meantime can help you feel more comfortable.
If your symptoms are bothersome or aren’t going away, talk to your healthcare team. They may need to evaluate you further to see if there is another cause.
Frequently asked questions
While silodosin does make it easier for you to pee, it doesn’t typically make you pee more. In fact, it’s likely to make you pee less often. One of the symptoms of BPH is needing to pee more frequently because you’re unable to fully empty your bladder.
With silodosin, you may be able to empty your bladder more completely. And this means you shouldn’t need to use the bathroom as often.
Many common, mild silodosin side effects go away after your body gets used to the medication. This could be after a few days or weeks. For example, dizziness and headaches tend to improve over time.
But other side effects like ejaculation problems may continue the entire time you’re taking silodosin. They should go away if you stop silodosin. But don’t stop taking any medications without talking to your prescriber or pharmacist first.
No, silodosin doesn’t seem to cause kidney problems. But your kidneys remove it from the body. This means that you may take a lower dose of silodosin if you have kidney problems. Let your prescriber know if you have a history of kidney issues. And follow their instructions so you take a dose that’s right for you.
Silodosin shouldn’t directly affect sleep. But it may help you get a better night’s rest because you use the bathroom less often. Silodosin is intended to help you urinate less often. So you may not need to get up during the night as often to pee. In fact, one study noted that silodosin improved sleep quality for older men with BPH.
The bottom line
Silodosin (Rapaflo) is a medication used to treat symptoms of benign prostatic hyperplasia. It’s generally well tolerated but still has possible side effects. Common silodosin side effects include ejaculation problems, dizziness, and headaches. Diarrhea and cold symptoms are also possible. Many side effects improve after your body gets used to the medication.
If your symptoms aren’t going away, or if they’re getting worse, talk to your healthcare team. They can recommend next steps to help relieve your symptoms.
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References
Australian Prescriber. (2018). Silodosin for benign prostatic hypertrophy.
Camber Pharmaceuticals. (2024). Silodosin- silodosin capsule [package insert]. DailyMed.
Capogrosso, P., et al. (2015). Effects of silodosin on sexual function – realistic picture from the everyday clinical practice. Andrology.
Curran, M. P. (2012). Silodosin: Treatment of the signs and symptoms of benign prostatic hyperplasia. Drugs.
Kim, Y. W., et al. (2015). The effectiveness of silodosin for nocturnal polyuria in elderly men with benign prostatic hyperplasia: A multicenter study. International Neurology Journal.
Kobayashi, K., et al. (2009). Orgasm is preserved regardless of ejaculatory dysfunction with selective α1A-blocker administration. International Journal of Impotence Research.
National Institute of Diabetes and Digestive and Kidney Diseases. (2024). Enlarged prostate (benign prostatic hyperplasia).
Yamanishi, T., et al. (2015). Six-year follow up of silodosin monotherapy for the treatment of lower urinary tract symptoms suggestive of benign prostatic hyperplasia: What are the factors for continuation or withdrawal? International Journal of Urology.
Zaman, F., et al. (2012). The floppy iris syndrome – what urologists and ophthalmologists need to know. Current Urology.
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