Flomax (tamsulosin)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

  • Medical and Pharmacy Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Do I need a prescription for Flomax (tamsulosin)?

Yes

Why is Flomax (tamsulosin) prescribed to patients?

What are the side effects of Flomax (tamsulosin)?

The most common adverse effects of Flomax are

Other side effects include

More serious side effects of Flomax

The following have been observed in male patients during Flomax treatment:

What is the dosage for Flomax (tamsulosin)?

  • The recommended starting dose is 0.4 once daily about 30 minutes after the same meal time each day.
  • When taken on an empty stomach, more of the medication is absorbed.
  • This could cause a greater effect and potentially a drop in blood pressure.
  • The dose may be increased to 0.8 mg once daily after 2 to 4 weeks if the response is not adequate.
  • The capsules should not be crushed, chewed or opened.
Benign Prostatic Hyperplasia Quiz: Test Your BPH IQ

Which drugs or supplements interact with Flomax (tamsulosin)?

The elimination of Flomax from the body may be reduced by:

Reduced elimination may lead to increased side effects of Flomax. PDE-5 inhibitors (for example, vardenafil [Levitra, Staxyn], Adcirca, sildenafil [Viagra, Revatio], tadalafil [Cialis]) add to the blood pressure lowering effects of Flomax and may result in severe blood pressure reduction.

Is Flomax (tamsulosin) safe to use during pregnancy or while breastfeeding?

  • Flomax is not prescribed for women.
  • This medication is used only in men. It is not known if Flomax is secreted into human milk.

What else should I know about Flomax (tamsulosin)?

What preparations of Flomax (tamsulosin) are available?

Capsules: 0.4 mg.

How should I keep Flomax (tamsulosin) stored?

Capsules should be stored at room temperature, 15 C to 30 C (59 F to 86 F).

How does Flomax (tamsulosin) work?
  • In men, the tube which carries urine from the bladder through the penis (called the urethra) passes through the prostate gland. As men get older, the prostate gland enlarges, and the muscle cells within the prostate gland and the neck of the bladder (which controls the flow of urine) tighten. The combination of enlargement and tightening of muscles compresses the urethra and obstructs the flow of urine. This results in difficulty urinating and retention of urine within the bladder. The tightening or contraction of the muscle cells is controlled by nerves. One type of nerve, the alpha adrenergic nerves, cause the muscle cells to tighten by releasing a chemical related to epinephrine (adrenalin). Tamsulosin blocks the effects of this chemical on the muscle cells and causes the muscles to relax. This results in a decrease in obstruction to the flow of urine.
  • There are other drugs that block alpha adrenergic nerves throughout the body and which are used in treating diseases of the heart, blood vessels, and prostate for example, prazosin (Minipress), terazosin (Hytrin), doxazosin (Cardura), and alfuzosin (Uroxatral). Tamsulosin is more active against the alpha adrenergic nerves of the prostate and bladder neck than these other drugs and has a lesser effect on alpha adrenergic nerves elsewhere in the body. For this reason, tamsulosin causes fewer side effects, especially low blood pressure, than other alpha adrenergic blocking drugs. Moreover, tamsulosin therapy can be started at the optimum dose whereas other alpha adrenergic blocking drugs need to be started at low doses with the doses slowly increased over time in order to minimize the side effects.
When was Flomax (tamsulosin) approved by the FDA?

Tamsulosin was approved by the FDA in 1997.

Reference: FDA Prescribing Information

Benign Prostatic Hyperplasia Quiz: Test Your BPH IQ

Summary

Flomax (tamsulosin) is a drug prescribed for the treatment of benign prostatic hyperplasia (BPH, enlarged prostate). Side effects may include:

Drug interactions, warnings and precautions, and pregnancy and breastfeeding information should be reviewed prior to taking any medication.

Treatment & Diagnosis

Medications & Supplements

Prevention & Wellness

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See more info: tamsulosin on RxList
Reviewed on 7/11/2016
References
Reference: FDA Prescribing Information

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