FDA-filed SPL labeling · retrieved through openFDA

Tamsulosin

Tamsulosin is an alpha-1 blocker used to treat the signs and symptoms of benign prostatic hyperplasia (BPH), or enlarged prostate, in men.

Brand name Flomax
Drug classes ⓘ Adrenergic Alpha-antagonists
Rx Form 1 Route Oral
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 73 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

At a glance
Linked label effectiveJul 25, 2024
Clinical labels in scope ⓘ73
AvailabilityRx
Earliest approval/marketing year ⓘ1997
FDA-listed product records ⓘ184
Boxed warningNone found in compared labels
How we combine label and product data →
✓No current FDA shortage listed · checked Sep 15, 2026
⭐ Tamsulosin at a glance The quick version — the full detail is in the Patient Information Guide below.
💊
HelloPharmacist Editorial Team Bottom Line
Tamsulosin (Flomax) is an effective once-daily oral treatment for the urinary symptoms of BPH, helping relax the muscles in the prostate and bladder neck to improve urine flow. Take it 30 minutes after the same meal each day, and swallow the capsule whole. The most important things to watch for are dizziness when standing, and — though very rare — a prolonged painful erection, which requires emergency care.
How we write & review this content — our editorial policy →

📖 Tamsulosin: Patient Information Guide

A plain-language walkthrough of Tamsulosin — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.

🎯What it's used for▾

Tamsulosin is approved to treat the urinary signs and symptoms of benign prostatic hyperplasia (BPH) — an enlarged prostate — in adult men.

  • Flomax capsules (oral): treats signs and symptoms of BPH
  • Tamsulosin hydrochloride capsules (oral, generic): treats signs and symptoms of BPH
  • Neither Flomax nor tamsulosin hydrochloride capsules are approved to treat high blood pressure
⚙️How it works▾

BPH causes two types of urinary blockage. One is the physical bulk of an enlarged prostate pressing on the urethra. The other — often more important for symptoms — is that muscles in the prostate and bladder neck stay too tense, squeezing off urine flow. Tamsulosin is an alpha-1 adrenoceptor blocker: it selectively attaches to receptors (mainly the alpha-1A subtype, which makes up about 70% of alpha-1 receptors in the prostate) and stops nerve signals that keep those muscles tight. When the muscles relax, urine can flow more freely and BPH symptoms ease.

Because tamsulosin targets prostate receptors selectively, it has less effect on blood vessels elsewhere in the body compared to less selective alpha-blockers — though blood pressure effects can still occur.

💊How it's taken▾

Tamsulosin capsules are taken once daily by mouth, approximately 30 minutes after the same meal each day. Keeping a consistent food routine helps limit the chance of blood-pressure dips. If your doctor adjusts your dose upward and you then go several days without taking it, you should restart at the lower starting dose rather than jumping back to the higher one. Always swallow the capsule whole — crushing, chewing, or opening it is not safe.

  • Take at the same time each day, linked to the same meal
  • Do not crush, chew, or open the capsule
  • Restart at the lower dose if treatment is interrupted for several days
  • Follow your prescriber's guidance — do not adjust your own dose
🤒Side effects — in detail▾

The most commonly reported side effects with tamsulosin capsules include:

  • Dizziness — particularly when standing up quickly (affects roughly 15–17% of patients in studies)
  • Headache
  • Runny or stuffy nose (rhinitis)
  • Abnormal ejaculation — including decreased, absent, or retrograde (backward) ejaculation; more common at higher doses
  • Fatigue or weakness (asthenia)
  • Back pain
  • Diarrhea or nausea
  • Drowsiness

Serious reactions are less common but require prompt attention: fainting or a dangerous blood-pressure drop upon standing, a prolonged painful erection (priapism — seek emergency care immediately), or signs of a severe allergic reaction such as swelling of the face or throat, hives, or difficulty breathing.

⚠️Warnings & precautions▾
  • Dizziness and fainting (orthostatic hypotension): Standing up quickly can cause a sudden drop in blood pressure. Avoid activities where fainting could be dangerous, especially when first starting treatment.
  • Priapism (rare but serious): A persistent, painful erection unrelated to sexual activity has been reported rarely. If not treated promptly, it can cause permanent erectile dysfunction. Go to an emergency room immediately.
  • Intraoperative Floppy Iris Syndrome (IFIS): Tamsulosin — even if stopped before surgery — can cause a complication during cataract or glaucoma eye surgery in which the iris becomes floppy and hard to manage. Tell any eye surgeon about your tamsulosin use well in advance.
  • Prostate cancer screening: BPH and prostate cancer can coexist. Get screened before starting tamsulosin and periodically during treatment.
  • Sulfa allergy: Rare allergic reactions have been reported in patients with a sulfa allergy. Tell your doctor if you have one.
🔀What it interacts with▾

Tamsulosin is broken down in the liver by enzymes called CYP3A4 and CYP2D6. Anything that slows those enzymes can raise tamsulosin levels in your blood and increase side effects.

  • Strong CYP3A4 inhibitors (e.g., ketoconazole): Do NOT combine — levels of tamsulosin can more than double, raising the risk of dangerous blood-pressure drops
  • Moderate CYP3A4 inhibitors (e.g., erythromycin): Use with caution
  • Strong CYP2D6 inhibitors (e.g., paroxetine): Use with caution — raises tamsulosin exposure
  • Moderate CYP2D6 inhibitors (e.g., terbinafine): Use with caution
  • Cimetidine (heartburn medication): Use with caution, especially at higher tamsulosin doses, as it raises blood levels
  • Other alpha-blocker medications: Do not combine — additive blood-pressure lowering is expected
  • PDE5 inhibitors (e.g., sildenafil, tadalafil for erectile dysfunction): Both drug types lower blood pressure; combining them can cause a dangerous drop
  • Warfarin (blood thinner): Use with caution — a possible interaction exists; monitor closely

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

📋Before taking it▾
  • Tell your doctor if you are allergic to tamsulosin or any ingredient in the capsules, or if you have a sulfa allergy
  • Tell your eye surgeon that you take or have taken tamsulosin before any cataract or glaucoma surgery, even if you stopped taking it
  • Share a complete medication list with your doctor — especially antifungals, antibiotics, antidepressants, or erectile dysfunction drugs
  • Not approved for women or children — tamsulosin is indicated only in adult men with BPH
  • Older adults generally tolerate tamsulosin well, but may be more sensitive to dizziness and blood-pressure effects
  • Severe liver disease: Tamsulosin has not been studied in patients with severe hepatic impairment — discuss the risk with your doctor
  • End-stage kidney disease: Not studied in this group — discuss with your doctor
  • You should be screened for prostate cancer before starting and regularly during treatment, as BPH and prostate cancer can occur together
🚑If you take too much▾

Too much tamsulosin can cause blood pressure to drop dangerously low. The first steps are lying flat and keeping still to help restore blood pressure. If that's not enough, intravenous fluids or medications to raise blood pressure may be needed in a medical setting. Because tamsulosin binds very tightly to proteins in the blood, dialysis is unlikely to remove it effectively.

📡Pharmacodynamics — effects in the body▾

Tamsulosin works by blocking alpha-1 adrenoceptors — mainly the alpha-1A subtype — in the prostate and bladder neck, relaxing the smooth muscle there. This relaxation leads to an improved urine flow rate and a reduction in the obstructive and irritative symptoms of BPH. Studies on its urologic effects have been conducted in adults with BPH.

🔬Pharmacokinetics — how your body processes it▾

When taken by mouth with food, tamsulosin is well absorbed and reaches its peak blood level in about 6–7 hours; on an empty stomach, peak levels are reached a couple of hours sooner but are also 40–70% higher, which is why consistent dosing with food is recommended. The drug is very extensively bound to proteins in the blood (94–99%) and is broken down primarily by liver enzymes CYP3A4 and CYP2D6, with less than 10% leaving the body unchanged in urine. Most of the drug is excreted in urine (about 76%), with the rest in stool, and the effective half-life (how long it takes the body to clear half the drug) is roughly 14–15 hours with regular once-daily dosing, allowing stable levels to build up within about five days.

📦How to store it▾

Store at 25°C (77°F); excursions permitted to 15°C–30°C (59°F–86°F) .

📄 Written from Tamsulosin’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →

18

Supplements & herbs that interact with Tamsulosin

18 supplements and herbal products have documented interactions with Tamsulosin in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 1
  • Moderate · 8
  • Minor · 9
ACTIVATED CHARCOAL Major BUTCHER'S BROOM Moderate COFFEE CHARCOAL Moderate EUROPEAN MANDRAKE Moderate GLUCOMANNAN Moderate GUAR GUM Moderate GUM ARABIC Moderate SLIPPERY ELM Moderate +10 more
Every supplement checked against Tamsulosin — ranked by severity The full interaction hub: 1 major · 8 moderate · 9 minor · every one linked to its full report. Check Tamsulosin against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

🩺 Pharmacist Counseling Corner

Quick, plain-English answers to the questions patients ask most about Tamsulosin — the kind of thing our pharmacy team would talk through with you at the counter.

What exactly does tamsulosin do for my prostate? ▾
Your prostate contains tiny muscle fibers that can squeeze too tight when the prostate is enlarged, making it hard to urinate. Tamsulosin blocks the signals that keep those muscles tense, so they relax and urine can flow more easily. It won't shrink the prostate itself, but most men notice their stream improves and the urgency and frequent trips to the bathroom ease up.
Does it matter when I take it or whether I eat first? ▾
Yes — timing really does matter with this one. Take your capsule about 30 minutes after the same meal every day. Taking it on an empty stomach pushes blood levels much higher, which raises your risk of dizziness or lightheadedness. Pick a meal that works for your routine and stick with it every day.
What side effects should I actually expect? ▾
The most common one is dizziness, especially when you stand up quickly — this affects a meaningful number of men, particularly in the first few weeks. You might also notice a runny or stuffy nose, mild fatigue, headache, or changes in ejaculation (some men have less fluid or ejaculate backward — this is harmless but worth knowing about). Most of these ease up over time. If you ever faint, or if you get a painful erection that won't go away, that's an emergency — get help right away.
I'm also taking a pill for erectile dysfunction. Is that okay? ▾
You need to be careful with that combination. Drugs like sildenafil or tadalafil and tamsulosin both lower blood pressure, and together they can cause a significant drop that makes you feel faint or dizzy. Let both your prescribers know what you're taking so they can weigh the risks and watch you more closely.
I'm planning to have cataract surgery — does tamsulosin affect that? ▾
This is really important to share with your eye surgeon before the operation. Tamsulosin — even if you've already stopped taking it — can cause a complication during cataract or glaucoma surgery called Intraoperative Floppy Iris Syndrome, where the iris becomes floppy and difficult to manage. Your surgeon can plan ahead and use special tools if they know about it. Don't stop tamsulosin on your own without talking to your doctor first; the benefit of stopping before surgery hasn't been clearly established.
Can I open or crush the capsule if I have trouble swallowing it? ▾
No — please don't. Tamsulosin hydrochloride capsules must be swallowed whole. Opening, crushing, or chewing them can change how the drug is absorbed and could lead to much higher levels in your blood, increasing the risk of side effects like dizziness or a dangerous blood-pressure drop. If swallowing capsules is a real problem, talk to your pharmacist or doctor about solutions.
Is Tamsulosin available over the counter? ▾
Tamsulosin is dispensed by prescription according to its FDA labeling, so it isn't sold over the counter. Your prescriber and pharmacist will determine if it's appropriate for you.
When was Tamsulosin first available? ▾
Tamsulosin has been available in the United States since at least 1997, based on FDA approval history (Drugs@FDA) and product marketing records.
Who makes Tamsulosin? ▾
Tamsulosin is supplied by 67 manufacturers listed in the FDA NDC Directory, including Bryant Ranch Prepack, NuCare Pharmaceuticals,Inc., Remedyrepack Inc..

💬 Answers drafted from Tamsulosin’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →

🧰 Keep exploring

📊Tamsulosin supplement interactions18 checked — ranked by severity 🌿Drug & Supplement CheckerTamsulosin vs. vitamins & herbs 💬Ask a PharmacistFree answer, usually < 24h 🔎NDC & pricing lookupFind Tamsulosin NDCs & costs 🅰️Browse Drugs A–ZLook up any medication

💊 How Tamsulosin comes

Tamsulosin is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Capsule

By mouth
Brands Flomax
How this form is used
What it may be used for
  • Flomax capsules are indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH)
  • Tamsulosin hydrochloride capsules are indicated for the treatment of the signs and symptoms of BPH
  • Flomax capsules are not approved for the treatment of high blood pressure
  • Tamsulosin hydrochloride capsules are not approved for the treatment of high blood pressure
Important instructions
  • Flomax and tamsulosin hydrochloride capsules are taken by mouth once daily, approximately 30 minutes after the same meal each day
  • Flomax and tamsulosin hydrochloride capsules must be swallowed whole — do not crush, chew, or open them
  • If Flomax or tamsulosin hydrochloride capsule therapy is interrupted for several days, restart at the lower starting dose
  • Flomax and tamsulosin hydrochloride capsules should not be used with strong CYP3A4 inhibitors such as ketoconazole
Available strengths 1 strength
0.4 mg
173 FDA-listed product records ⓘ

📊 Tamsulosin across the U.S. market

How Tamsulosin appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

1
Dose forms ⓘ
67
Manufacturers
2
Brand names
184
FDA-listed product records ⓘ
1997
First marketed ⓘ

Also listed with the FDA, not a patient dose form: Powder (11) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.

Bryant Ranch Prepack10%
NuCare Pharmaceuticals,Inc.10%
Remedyrepack Inc.9%
A-S Medication Solutions8%
PD-Rx Pharmaceuticals, Inc.5%
Proficient Rx LP4%
Other makers53%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

📈 How widely Tamsulosin is used

A general measure of how commonly Tamsulosin is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Tamsulosin is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

2,108,678
Medicaid prescriptions filled (Q1–Q4 2025)
$22.4M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Tamsulosin prescribed? Of the 1,594 medications we measure, Tamsulosin ranks #107 by Medicaid prescriptions — more than 93% of them.

Where Tamsulosin ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5
Total prescriptions — #107 of 1,594
#102 Nystatin 2,190,507 Rx #103 Benzonatate 2,171,868 Rx #104 Apixaban 2,151,899 Rx #105 Lidocaine Transdermal... 2,146,915 Rx #106 Baclofen 2,144,009 Rx #107 Tamsulosin 2,108,678 Rx #108 Lorazepam 2,080,821 Rx #109 Pregabalin 2,058,308 Rx #110 Dexamethasone 2,033,076 Rx #111 Prazosin 2,024,285 Rx #112 Potassium 1,949,817 Rx

Utilization by Tamsulosin product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

tamsulosin hydrochloride 0.4 MG Oral Capsule

2,108,678 Medicaid prescriptions (Q1–Q4 2025) 100% of Tamsulosin prescriptions shown $22.4M gross reimbursement (before rebates) ≈ $11 per prescription (gross)

Summed across the 24 of 316 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 863669

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Tamsulosin, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 24 of 316 listed Tamsulosin NDCs with Medicaid activity.

🔍 Compare Tamsulosin products

A representative set of FDA-listed product records for Tamsulosin — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Showing 184 of 184 products — FDA National Drug Code Directory. See every product, package size and price: browse all 184 Tamsulosin NDCs →

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Tamsulosin RxCUI 77492 2 dose forms · 2 strengths
  1. Dose form (SCDF) Extended Release Oral Tablet RxCUI 608594 No current FDA listing
    Clinical drug / strength (SCD) hydrochloride 0.4 MG RxCUI 863675
  2. Dose form (SCDF) Oral Capsule RxCUI 374021 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 0.4 MG RxCUI 863669

Look up RxCUI 77492 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

🏷️ Sold under these brand names

Flomax

🏭 Manufacturers & labelers

Bryant Ranch Prepack 16 NuCare Pharmaceuticals,Inc. 16 Remedyrepack Inc. 14 A-S Medication Solutions 13 PD-Rx Pharmaceuticals, Inc. 8 Proficient Rx LP 7 RedPharm Drug, Inc. 7 Aphena Pharma Solutions - Tennessee, LLC 6 Cardinal Health 107, LLC 5 Preferred Pharmaceuticals, Inc. 5 Aurobindo Pharma Limited 4 AvPAK 3 Zydus Lifesciences Limited 3 NCS HealthCare of KY, LLC dba Vangard Labs 3 American Health Packaging 3 Major Pharmaceuticals 3 Quallent Pharmaceuticals Health LLC 2 Direct_Rx 2 Northwind Pharmaceuticals 2 Preferred Pharmaceuticals Inc. 2 NorthStar Rx LLC 2 Synthon Pharmaceuticals, Inc. 2 McKesson Corporation dba SKY Packaging 2 Macleods Pharmaceuticals Limited 2

…and 16 more on the FDA NDC directory.

RxNorm drug class

Tamsulosin belongs to the alpha-Adrenergic Blocker class.

Pharmacologic class alpha-Adrenergic Blocker
Drug family (ATC) Alpha-adrenoreceptor antagonists
How it works Adrenergic alpha-Antagonists

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

🔬 Where this comes from

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Jul 25, 2024
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Tamsulosin.
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Tamsulosin after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
73
NDC products indexed
184
Distinct labelers/manufacturers represented
67
Linked representative label ⓘ
RedPharm Drug, Inc.
Linked label effective
Jul 25, 2024
Composite sections available
23
Linked SPL Set ID
b3384748-92f1-0b49-e053-2a95a90abc73
Linked SPL Document ID
1e1dfa4a-3fdc-4703-e063-6394a90a9d97
Open the linked representative label on DailyMed ↗

How we combine label and product data

HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 73 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.

For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. RedPharm Drug, Inc. is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.

This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.