Tamsulosin (Flomax) Dosages for Adults: Your GoodRx Guide

Tamsulosin (Flomax) is a prescription alpha blocker medication. It’s used to improve urinary symptoms caused by benign prostatic hyperplasia (BPH). This can include using the bathroom frequently and a weak urine stream. Tamsulosin comes as a capsule that you take by mouth.

In this guide, we’ll review the typical tamsulosin dosages. Keep in mind that these recommendations come from the manufacturer. If you have any questions or concerns about your tamsulosin dosage, talk to your healthcare provider or pharmacist.

What’s the typical tamsulosin dosage for adults?

Tamsulosin is available as a 0.4 mg capsule. And it’s only approved for treating urinary symptoms of BPH in adults. Sometimes tamsulosin is used off-label to help you pass a kidney stone. It’s not approved for use in children.

Benign prostatic hyperplasia

To help improve your BPH symptoms, the typical tamsulosin dosage is 0.4 mg by mouth once daily. You should take it at the same time every day, about 30 minutes after a meal.

If this dosage doesn’t improve your symptoms, your healthcare provider may have you take 0.8 mg by mouth once daily. In this case, you’ll take two tamsulosin capsules together for your dose.

It’s important to swallow tamsulosin capsules whole. Don’t crush, chew, or open the capsules.

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Are there any dosage adjustments for medical conditions or interactions?

Sometimes certain medical conditions require a lower medication dosage. This is also the case with certain interactions, too. Below we’ll discuss a few factors that your healthcare provider may consider when determining the best dosage for you.

Kidney and liver problems

There aren't any recommended dosage adjustments for kidney or liver problems. But tamsulosin hasn’t been studied in people with severe kidney or liver disease. Before taking tamsulosin, let your healthcare provider know your full medical history.

Interactions

Certain medications can affect how well your body breaks down and gets rid of tamsulosin. In some cases, these combinations should be avoided. Examples of these medications include ketoconazole and clarithromycin (Biaxin XL).

With other combinations, certain people may need to limit their tamsulosin dosage to 0.4 mg once daily. Examples include erythromycin (Ery-Tab), terbinafine, and paroxetine (Paxil).

Those are just a few examples, though. Be sure that your healthcare provider and pharmacist have a current list of your medications. They can check to see if any of them interact with tamsulosin.

What happens if you miss a dose of tamsulosin?

If you forget to take a dose of tamsulosin, take it as soon as possible the same day. But if you don’t remember until the next day, skip the missed dose and continue with your next scheduled dose. Don’t double your dose or take more than one dose in the same day.

If you’re frequently forgetting to take your dose, you might try medication reminder apps and pill organizers with alerts to help you stay on track.

What should you do if you take too much tamsulosin?

Taking too much of any medication can increase your risk of side effects. If you take too much tamsulosin, you may experience low blood pressure (hypotension). This can cause dizziness or fainting.

If you think you’ve taken too much tamsulosin, contact your healthcare provider, or Poison Control at 1-800-222-1222, right away. If your symptoms feel life-threatening or severe, get immediate medical attention.

How to save on tamsulosin

There are many ways to save on tamsulosin, which is available as both a brand-name and generic medication.

GoodRx can help you save over 60% off the average retail price of the generic version. Generic tamsulosin’s price at certain pharmacies is as low as $4.80 with a free GoodRx discount.

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Written by:

Brian Leonard, PharmD, BCACP, BCGP

Brian Leonard earned his doctorate in pharmacy from the University of Florida College of Pharmacy and is board certified in Ambulatory Care and Geriatric Pharmacy.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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