Flomax – Information, Uses, Side Effects and Dosage


Drug Trade Names: Flomax, Tamsulosin Hydrochloride

Category: Alpha-adrenergic blocker

Generic Name: tamsulosin hydrochloride

Introduction and Quick Information:


Flomax is an anti-adrenergic agent manufactured by Boehringer Ingelheim for the treatment of benign prostate hyperplasia (BPH), in which the prostate gland becomes enlarged. In this disease, there is a non cancerous increase in the size of the prostate gland, making it difficult for the patient to urinate. 

It works by blocking alpha-1 adrenergic receptors, thereby relaxing the muscles of prostate gland and neck of the urinary bladder, which helps in easy urination. It is not approved for use in women and children. 

Is It Approved By U.S. FDA?     

Flomax was approved by FDA on April 15, 1997, on application from BOEHRINGER INGELHEIM and its license expired in October 2009. Then, again on application by IMPAX LABS, FDA approved Flomax on March 2, 2010. Flomax is considered as an effective drug for the treatment of benign prostatic hyperplasia (BPH) by FDA.   

Usage and Benefits of Flomax:

Some of the problems for which Flomax provides an effective solution are listed below:

  • An enlarged prostate as in benign prostatic hyperplasia
  • Frequent urination
  • Incomplete emptying of urinary bladder while urinating
  • Kidney stones

This medication can be used for other uses as well. Consult your doctor or pharmacist for further information. 

Flomax Side Effects:

Some of the side effects of Flomax are:

  • Weakness
  • Drowsiness
  • Sore throat and cough
  • Nasal Congestion
  • Dizziness
  • Nausea
  • Diarrhea
  • Nasal rhinitis
  • Headache
  • Blurred vision
  • Sleep problems 
  • Back pain
  • Abnormal ejaculation
  • Fever or chills

Consult your doctor before using this medication, if you have:

  • Prostate cancer
  • Undergone cataract surgery
  • Coronary artery disease
  • Sulfa allergy

General Recommended Dosages of Flomax:

Flomax is available in capsules of 0.4 mg, which is to be taken orally 30 minutes after the same meal each day. If the response is not adequate by using 0.4 mg after 2-4 weeks of therapy, the dose might be increased to 0.8 mg, once daily. If your therapy gets interrupted in between, you can restart it with 0.4 mg capsule, once daily. 

In Case I Miss the Dose?


If you miss a dose, skip it and take next scheduled dose if it is time for next dose. But if there is enough time for next dose, then take the missed dose when you remember. Do not take an extra dose to make up for the mixed dose.

In Case I Take Overdose?

Seek immediate medical attention in case of overdose.  You may experience some side-effects due to overdose like dizziness, headache etc.   

Drug Interactions of Flomax:

Here is a list of medicines that can react with Flomax and should not be taken together:

  • alfuzosin hydrochloride (Uroxatral)
  • silodosin (Rapaflo)
  • phentolamine mesylate (Oraverse)
  • labetalol hydrochloride (Trandate)
  • clarithromycin (Biaxin)
  • miconazole (Monistat)
  • isoniazid (Liniazid)
  • chlorpromazine hydrochloride (Chlorpromazine hydrochloride)
  • diclofenac sodium (Cambia)
  • pergolide mesylate (Permax)
  • imatinib mesylate (Gleevec)
  • cimetidine (Cimetidine)

Inform your doctor or pharmacist about any medicine that you have been taking before starting Flomax, to avoid the incidence of drug interaction.

Lifestyle and food habits you must follow when on Flomax:

Lifestyle suitable when on Flomax should involve following features:

  • Regular check up of prostate and blood pressure
  • When you are sitting or lying down, don’t get up very quickly.
  • Avoid standing for long hours
  • Avoid alcohol consumption
  • Prevent yourself from falling
  • Do not drive or perform activities requiring alertness

You should also follow a healthy and nutritional diet.

How Safe Is Flomax for Pregnant Women or Nursing Mothers?

Flomax is categorized under pregnancy category B by the U.S. FDA. It has not been approved by the U.S FDA for use in women and children. 

Women are unlikely to use this medicine. Data is not available whether it is excreted in breastmilk or not. Therefore, its effect on lactating women is unknown. 

Complications and Conditions possible due to prolonged use of Flomax:

Prolonged use of Flomax may affect the blood vessels and other tissue of brain causing a severe headache that can last for a long period. It also affects the prostate gland muscles causing abnormal ejaculation. It can also cause dizziness which can make it difficult for the patient to drive or indulge in any other activity that might require alertness. 

Thus, avoid prolonged use of Flomax and follow your doctor’s prescription for best results.

Availability of Flomax:

Flomax in the strength of 0.4 mg and 0.8mg is available on prescription in many U.S. FDA authorized health centers and government hospitals.