Generic name: Tamsulosin.

Flomax is an alpha-blocker. It smooths muscles in the prostate and the neck of the bladder by blocking the nerve endings (alpha receptors) in the affected area. 

Quick Facts About Flomax


Used to alleviate the urinary symptoms of benign prostatic hyperplasia (BHP).

Flomax Dosage

Take exactly as prescribed at the same time every day, one half hour after a meal. Do not stop treatment suddenly without the permission of your doctor.

  • Usual adult dose: initially — 0.4 milligram once per day. Doctor may increase dose by 0.8 milligrams per day.
  • Usual child dose: not prescribed for children.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses. Inform your doctor if several consecutive doses are missed and resume original dose of 0.4 milligram per day.

Flomax Side Effects

Overdose symptoms:

more severe side effects. If you suspect an overdose, immediately seek medical attention.

More common side effects: dizziness, headache, weakness.

Less common Flomax side effects: abdominal pain, abnormal heart rhythms, anxiety, arthritis, breathing difficulty, bronchitis, chest pain, cold or flu-like symptoms, conjunctivitis, constipation, cough, diarrhea, difficulty sleeping, dry mouth, eye pain, fainting, fever, flushing, frequent urinating, gas, itching, joint pain, low blood pressure, muscle pain, nervousness, nosebleed, pain in back, neck, shoulders, arms, or legs, “pins and needles” in hands and feet, rash, sweating, swelling of the face, arms, or legs, tiredness, urinary infection, vision problems, vomiting, worsening of asthma. Rare side effects: abnormal sexual function or decrease in sex drive, depression, fluid retention, weight gain.


Inform your doctor before combining Flomax with:

beta-blockers such as betaxolol (Betoptic and Kerlone) or timolol (Blocadren); blood-pressure-lowering drugs; clonidine (Catapres); indomethacin (Indocin).

Avoid over-the-counter stimulants. 

Special Cautions

Effects of Flomax on pregnant women and nursing mothers not known. If pregnant, planning to become pregnant, or breastfeeding, inform your doctor immediately. Potential benefits may outweigh potential risks.

Seniors may be more sensitive to side effects.

Not prescribed for children.

  • Should not take if sensitive or allergic to Flomax or any alpha-blockers.
  • Doctor may change dose and recommend taking medication at bedtime if dizziness or fainting are experienced, especially within the first 2 to 6 hours after first dose.
  • May impair your ability to drive a car or operate machinery. Do not take part in any activity that requires mental alertness until adjusted to medication (at least 24 hours).
  • Inform your doctor before taking if you have high blood cholesterol levels.
  • Flomax may improve cholesterol levels and increase the HDL/LDL ratio.


HealthSurvey.org provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Flomax side effects, please contact your healthcare provider.