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Silodosin Side Effects

It is possible that some side effects of silodosin may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to silodosin: oral capsule

As well as its needed effects, silodosin may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking silodosin, check with your doctor immediately:

Less common
  • Chills
  • cold sweats
  • confusion
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
Incidence not known
  • Abdominal or stomach pain
  • clay-colored stools
  • dark urine
  • fever
  • headache
  • itching
  • loss of appetite
  • nausea
  • pinpoint red or purple spots on the skin
  • rash
  • skin blisters
  • unpleasant breath odor
  • unusual tiredness or weakness
  • vomiting of blood
  • yellow eyes or skin

Some silodosin side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Change or problem with discharge of semen
Less common
  • Diarrhea
  • muscle aches
  • sore throat
  • stuffy or runny nose

For Healthcare Professionals

Applies to silodosin: oral capsule


Retrograde ejaculation was reversible upon discontinuation of silodosin.[Ref]

Genitourinary side effects have included retrograde ejaculation (28.1%) and one case of priapism in U.S. clinical trials.[Ref]

Nervous system

Nervous system side effects have included dizziness (3.2%), headache (2.4%), and insomnia (1% to 2%) in U.S. clinical trials.[Ref]


Gastrointestinal side effects have included diarrhea (2.6%) and abdominal pain (1% to 2%) in U.S. clinical trials.[Ref]


Cardiovascular side effects have included orthostatic hypotension (2.6%) in U.S. clinical trials. One case of syncope occurred in a patient taking prazosin concomitantly with silodosin.[Ref]


Respiratory side effects have included nasopharyngitis (2.4%), nasal congestion (2.1%), sinusitis (1% to 2%), and rhinorrhea (1% to 2%) in U.S. clinical trials.[Ref]


Ocular side effects including Intraoperative floppy iris syndrome (IRIS) have been observed in some patients undergoing phacoemulsification cataract surgery while being treated with alpha-1 blockers.[Ref]

Most reports were in patients treated with an alpha-1 blocker at the time IFIS occurred, but in some instances the alpha-1 blocker had been stopped prior to surgery. The manufacturer recommends that patients be questioned to determine whether or not they have taken alpha-1 blockers prior to being considered for cataract surgery. If it is determined that the patient has taken an alpha-1 blocker, the patient's ophthalmologist should be prepared for possible modifications to their surgical technique that may be necessary should IFIS be observed during the procedure.[Ref]


Other side effects occurring in 1% to 2% of patients in clinical trials included asthenia and increased PSA levels.[Ref]


Dermatologic side effects reported postmarketing have included toxic skin eruption and purpura.
Postmarketing reports: Pruritus, urticaria[Ref]


Hepatic side effects reported postmarketing have included jaundice and impaired hepatic function associated with increased transaminase values.[Ref]


Postmarketing reports: Immune system disorders including allergic-type reactions, not limited to skin reactions including swollen tongue and pharyngeal edema


1. "Product Information. Rapaflo (silodosin)." Watson Pharmaceuticals, Corona, CA.

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