Indications
Silodosin is used in men to relieve urinary symptoms caused by an enlarged prostate (benign prostatic hyperplasia, BPH). These include a weak stream, difficulty starting, needing to pass urine often or urgently, and waking at night to urinate. It does not shrink the prostate.
How It Works
Silodosin is an alpha-1 blocker. It relaxes the muscle in the prostate and the neck of the bladder, so urine flows more easily.
Dosage and Administration
Adults: usually 8 mg once a day, taken with food at the same time each day. People with moderate kidney problems usually start with 4 mg once a day. Swallow the capsule whole; if it is hard to swallow, the capsule can be opened and the contents sprinkled on a spoonful of soft food and swallowed straight away without chewing. Improvement is often felt within 1 to 2 weeks.
Interactions
Do not take with strong blockers of the liver enzyme CYP3A4, such as Ketoconazole, Itraconazole, Clarithromycin or Ritonavir, as they raise silodosin levels a lot. Avoid other alpha blockers (such as Tamsulosin, Alfuzosin, Doxazosin). Medicines for erectile dysfunction (Sildenafil, Tadalafil) and blood pressure medicines can add to the fall in blood pressure and cause dizziness.
Contraindications
Allergy to silodosin or any ingredient; severe kidney disease; severe liver disease; and use with strong CYP3A4 blockers. It is not for use in women or children.
Side Effects
Very common: little or no semen at ejaculation (retrograde ejaculation). This is harmless and goes away after stopping, but it may reduce fertility for a while. Other effects: dizziness, especially on standing up, blocked or runny nose, diarrhoea and headache.
Get urgent medical help if you faint, have swelling of the face, lips or throat, difficulty breathing, a severe rash, or a painful erection lasting more than 4 hours.
Pregnancy and Lactation
Silodosin is a medicine for men only and is not used in pregnancy or breastfeeding.
Precautions and Warnings
Stand up slowly, especially after the first doses, and sit or lie down if you feel dizzy or light-headed. Do not drive until you know how it affects you. If you are planning cataract or other eye surgery, tell the eye surgeon you take or have taken silodosin, as it can affect the pupil during surgery. Your doctor should check for prostate cancer before and during treatment, as the symptoms can be similar. Tell your doctor about kidney or liver problems.
Overdose
Too much can cause a large fall in blood pressure, with dizziness or fainting. Lie down with legs raised and get medical help straight away.
Therapeutic Class
Alpha-1 adrenergic blocker (medicine for enlarged prostate).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.