1 What is Flomax?

Brand: Flomax

Generic: Tamsulosin

Flomax is an alpha-adrenergic drug, used to treat the symptoms of benign prostatic hypertrophy (BPH) or enlargement of the prostate gland in men. This medication relaxes the muscles in the bladder and prostate to relieve difficulty in starting your urine flow, weak stream and frequent or urgent urination, particularly at night.

Tamsulosin is also used to remove kidney stones by excreting them through the urine. This medication can also treat bladder disorders in women.


Read your medication guide and follow your doctor’s prescription at all times.

  • Take tamsulosin orally/ by mouth 30 minutes after meals, once a day per doctor’s prescription. Do not break, crush, chew or open the capsule of this medication and swallow it as whole.
  • The dosage depends on your medical condition or treatment response. Do not adjust your dose without your doctor’s recommendation.
  • Avoid alcohol intake and activities that require mental alertness (i.e. driving, operating machineries) because this medication can cause dizziness.
  • Likewise, slowly rise from sitting or lying position to prevent lightheadedness or fainting.
  • Continue taking this medication on regular schedule (same time of the day). Do not stop taking this medication abruptly without consulting your doctor.

Inform your doctor immediately if your condition aggravates or does not improve.

Take your missed dose as soon as possible. However, make sure that the time interval between the missed and the next dose is not too close. Otherwise, stick with the regular schedule and leave out the missed dose. Do not double dose to cover up a missed dose. Record your missed dose and inform your doctor immediately if you missed several doses.


Tamsulosin may interact with:

  • Prazosin, terazosin or other alpha blocker medications
  • Sildenafil, tadalafil or other medications for erectile dysfunction and pulmonary hypertension
  • Ketoconazole or other azole antifungal drugs
  • Clarithromycin or other macrolide antibiotics
  • Nefazodone
  • Ritonavir
  • Telithromycin 
  • Medications that cause drowsiness such as antihistamine (i.e. cetirizine, diphenhydramine), sleeping pills, anti- anxiety drugs (i.e. alprazolam, diazepam), muscle relaxants and narcotic pain relievers (i.e. codeine).

Some drugs may either lessen the beneficial effects or worsen the side effects of tamsulosin. Likewise, tamsulosin may make some drugs less efficient or intensify their side effects.

Make sure to inform your doctor about all other drugs you are currently taking or using (prescribed and non-prescribed medications including vitamins, minerals and herbal products) to check for possible drug interaction with tamsulosin.

Never alter the doses of other medications while on tamsulosin neither stop nor start any medicine without the doctor’s recommendation.

Side Effects

There are no side effects known aside from a possible allergic reaction in people who have previous or unknown hypersensitivity to the drug.

Watch out for signs of allergic reactions such as:

  • Rash
  • Itching
  • Swelling


Before taking tamsulosin tell your health care provider if you have/are:

  • any allergies to any substance, food or medication, particularly to tamsulosin (Flomax)
  • medical history or a present condition such as:
  • pregnant, planning to get pregnant or currently breastfeeding a child ( Tamsulosin has no expected harmful effects to the unborn child and it is unknown if this medication can pass through breast milk that may harm the nursing baby. The risks and benefits of taking this drug upon your pregnancy must be discussed well with your doctor.)

2 Related Clinical Trials