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AHFS Consumer Medication Information [Internet]. Bethesda (MD): American Society of Health-System Pharmacists; 2000-2011.

AHFS Consumer Medication Information.

Tamsulosin(tam soo' loe sin)

Last Revision: January 15, 2012.

Why is this medication prescribed?

Tamsulosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH) which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Tamsulosin is in a class of medications called alpha blockers. It works by relaxing the muscles in the prostate and bladder so that urine can flow easily.

How should this medicine be used?

Tamsulosin comes as a capsule to take by mouth. It is usually taken once a day. Take tamsulosin 30 minutes after the same meal each day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tamsulosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow tamsulosin capsules whole; do not split, chew, crush, or open them.

Your doctor will probably start you on a low dose of tamsulosin and may increase your dose after 2 to 4 weeks.

Tamsulosin may help control your condition, but it will not cure it. Continue to take tamsulosin even if you feel well. Do not stop taking tamsulosin without talking to your doctor.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking tamsulosin,

  • tell your doctor and pharmacist if you are allergic to tamsulosin, sulfa medications, or any other medications.

  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take. Be sure to mention any of the following: other alpha blocker medications such as alfuzosin (Uroxatral), doxazosin (Cardura), prazosin (Minipress), and terazosin (Hytrin); anticoagulants ('blood thinners') such as warfarin (Coumadin); cimetidine (Tagamet); and medications for erectile dysfunction (ED) such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra); Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.

  • tell your doctor if you have or have ever had prostate cancer or liver or kidney disease.

  • you should know that tamsulosin is only for use in men. Women should not take tamsulosin, especially if they are pregnant or could become pregnant or are breast-feeding. If a pregnant woman takes tamsulosin, she should call her doctor.

  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking tamsulosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken tamsulosin.

  • you should know that this medication may make you drowsy or dizzy. Do not drive a car, operate machinery, or perform dangerous tasks until you know how this medication affects you.

  • you should know that tamsulosin may cause dizziness, lightheadedness, a spinning sensation, and fainting, especially when you get up too quickly from a lying position. This is more common when you first start taking tamsulosin or after your dose is increased. To help avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. Call your doctor if these symptoms are severe or do not go away.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. If you interrupt your treatment for several days or longer, call your doctor before restarting the medication, especially if you take more than one capsule of tamsulosin a day.

What side effects can this medication cause?

Tamsulosin may cause side effects. Tell your doctor if any of these symptoms or those in the SPECIAL PRECAUTIONS section are severe or do not go away:

  • sleepiness

  • difficulty falling asleep or staying asleep

  • weakness

  • back pain

  • diarrhea

  • runny or stuffy nose

  • pain or pressure in the face

  • sore throat, cough, fever, chills, or other signs of infection

  • blurred vision

  • difficulty ejaculating

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

  • painful erection of the penis that lasts for hours

  • rash

  • itching

  • hives

  • swelling of the eyes, face, tongue, lips, throat, arms, hands, feet, ankles, or lower legs

What storage conditions are needed for this medicine?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

  • dizziness

  • fainting

  • blurred vision

  • upset stomach

  • headache

What other information should I know?

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS® Consumer Medication Information. © Copyright, 2011. The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

The following brand names are from RxNorm, a standardized nomenclature for clinical drugs produced by the National Library of Medicine:

Brand names

  • Flomax

Brand names of combination products

  • Jalyn (containing Dutasteride and tamsulosin)

What works?

  • Fact sheet: Medications for enlarged prostate Fact sheet: Medications for enlarged prostate
    Most men who have prostate problems either wait a while to see how their symptoms develop or take medication. Medication is often used when the symptoms are not bad enough to warrant surgery, but have become too bothersome to cope with. The man might have to get up several times a night to urinate, or constantly feel the need to urinate during the day too because his bladder will no longer empty properly. These typical symptoms of an enlarged prostate can become a real burden.
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