Prescription medication · Alpha-1 Adrenergic Blocker
tamsulosin
Also sold as Flomax. This medicine treats the symptoms of an enlarged prostate, also known as benign prostatic hyperplasia (BPH).
Data updated 2026-05-15
- 18,628
- FDA reportsModerately reported
- 18
- InteractionsSeveral interactions
- 99% less
- Generic vs brandHuge savings
- In shortage
- FDA status
What the data shows
tamsulosin (Flomax) is a prescription Alpha-1 Adrenergic Blocker, reported at a middle-of-the-pack volume (18,628 FDA reports), whose generic costs a fraction of the brand (about 99% less).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
tamsulosin (Flomax) is a prescription Alpha-1 Adrenergic Blocker. This medicine treats the symptoms of an enlarged prostate, also known as benign prostatic hyperplasia (BPH).
Tamsulosin (Flomax) helps to improve urination in men with enlarged prostate glands. It relaxes the muscles in the prostate and bladder, making it easier to urinate.
Verify with FDA → · CMS NADAC pricing →
Drug Shortage Alert
tamsulosin is currently listed as to be discontinued by the FDA. Affected manufacturer: Sandoz Inc..
View all drug shortages →Drug Pricing (NADAC)
Brand Price
$9.35/unit
Generic Price
$0.05/unit
Generic Savings
99%
Generic Available
Yes (9 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
NADAC price trail: TAMSULOSIN HCL 0.4 MG CAPSULE
Same CMS presentation as the headline generic unit price above (6 effective dates). Adjacent % compares consecutive NADAC releases for this description only, not a patient out-of-pocket quote. Latest step: -14.4% vs prior release.
| Effective | NADAC / unit | vs prior | NDCs |
|---|---|---|---|
| March 20, 2024 | $0.0580/EA | - | 1 |
| June 19, 2024 | $0.0539/EA | -7% | 1 |
| July 17, 2024 | $0.0460/EA | -14.7% | 3 |
| August 21, 2024 | $0.0547/EA | +18.9% | 1 |
| September 18, 2024 | $0.0545/EA | -0.3% | 1 |
| December 18, 2024 | $0.0466/EA | -14.4% | 30 |
What it does
This medicine treats the symptoms of an enlarged prostate, also known as benign prostatic hyperplasia (BPH).
Common side effects
Headache, Dizziness, Runny nose
Key warnings
Tamsulosin can cause a sudden drop in blood pressure when you stand up, leading to dizziness or fainting.
The sections below are summarized in plain English from tamsulosin's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Tamsulosin blocks alpha-1 adrenoceptors in the prostate and bladder. These receptors control muscle tightness. By blocking them, tamsulosin relaxes the muscles, which improves urine flow.
Side Effects (from patient reports)
Based on 18,628 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for tamsulosin, by number of reports
- Fatigue
Fatigue
1,417 reports
- Dyspnoea
Dyspnoea
1,332 reports
- Dizziness
Dizziness
1,131 reports
- Diarrhoea
Diarrhoea
1,121 reports
- Headache
Headache
883 reports
- Asthenia
Asthenia
842 reports
- Fall
Fall
839 reports
- Nausea
Nausea
808 reports
- Cough
Cough
711 reports
- Malaise
Malaise
652 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for tamsulosin each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where tamsulosin sits
tamsulosin has more FDA adverse-event reports than 53% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is tamsulosin; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 18,628 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
18,628
Reports Mentioning Death
2,065
11.1% of reports — not proof of cause
Hospitalization Reports
6,635
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | FATIGUE | 1,417 |
| 2 | DYSPNOEA | 1,332 |
| 3 | DIZZINESS | 1,131 |
| 4 | DIARRHOEA | 1,121 |
| 7 | HEADACHE | 883 |
| 8 | ASTHENIA | 842 |
| 9 | FALL | 839 |
| 10 | NAUSEA | 808 |
| 11 | COUGH | 711 |
| 12 | MALAISE | 652 |
| 13 | PRURITUS | 651 |
| 14 | ARTHRALGIA | 644 |
| 15 | DEATH | 639 |
| 16 | DECREASED APPETITE | 601 |
| 17 | PYREXIA | 586 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Tamsulosin can cause a sudden drop in blood pressure when you stand up, leading to dizziness or fainting. Avoid situations where you could get hurt if you faint. Tell your eye doctor if you are planning to have cataract or glaucoma surgery, as tamsulosin can cause complications during the procedure. You should be screened for prostate cancer before starting tamsulosin and regularly after.
Known Drug Interactions
7.7 Furosemide Tamsulosin hydrochloride capsules had no effect on the pharmacodynamics (excretion of electrolytes) of furosemide. While furosemide produced an 11% to 12% reduction in tamsulosin hydrochloride C max and AUC, these changes are expected to be clinically insignificant and do not require adjustment of the tamsulosin hydrochloride capsules dosage [see Clinical Pharmacology (12.3)].
Mechanism: Furosemide slightly lowers the level of tamsulosin in your system, but the effect is too small to change how the medicine works.
Tamsulosin hydrochloride capsules should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), in combination with strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, or in patients known to be CYP2D6 poor metabolizers, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg). Concomitant treatment with paroxetine (a strong inhibitor of CYP2D6) resulted in an increase in the C max and AUC of tamsulosin by a factor of 1.3 and 1.6, respectively [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)].
Mechanism: Paroxetine stops your body from breaking down tamsulosin normally, which leads to higher levels of the drug in your system. This can increase your risk of having side effects.
7.4 Warfarin A definitive drug-drug interaction study between tamsulosin hydrochloride and warfarin was not conducted. Caution should be exercised with concomitant administration of warfarin and tamsulosin hydrochloride capsules [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)].
Mechanism: There is not enough research to know exactly how these drugs interact, but taking them together might change how your blood clots. This could make your treatment less safe.
Tamsulosin hydrochloride capsules should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), in combination with strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, or in patients known to be CYP2D6 poor metabolizers, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg). The effects of concomitant administration of a moderate CYP3A4 inhibitor (e.g., erythromycin) on the pharmacokinetics of tamsulosin hydrochloride have not been evaluated [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)].
Mechanism: Erythromycin may slow down the way your body gets rid of tamsulosin, which could cause the drug to build up in your blood. This might lead to more side effects from the medicine.
Tamsulosin hydrochloride capsules should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), in combination with strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, or in patients known to be CYP2D6 poor metabolizers, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg). The effects of concomitant administration of a moderate CYP2D6 inhibitor (e.g., terbinafine) on the pharmacokinetics of tamsulosin hydrochloride have not been evaluated [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)].
Mechanism: Terbinafine slows down the body's ability to break down tamsulosin by blocking a specific liver enzyme. This can lead to higher levels of tamsulosin in your blood.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
Can women take tamsulosin?
Can I crush or chew the capsule?
What should I do if I feel dizzy after taking tamsulosin?
Can I take tamsulosin with other medications?
How long does it take for tamsulosin to work?
What if tamsulosin doesn't work for me?
Does tamsulosin affect my sex life?
Can I drink alcohol while taking tamsulosin?
What if I am having surgery?
How do I know if tamsulosin is working?
What are the common side effects of tamsulosin?
Does tamsulosin interact with other medications?
What drug class is tamsulosin?
Is there a generic version of tamsulosin?
What pregnancy or breastfeeding source fields are listed for tamsulosin?
Is tamsulosin currently in shortage?
Related Medications in Alpha-1 Adrenergic Blocker
Other drugs grouped near tamsulosin - same-class peers and common alternatives.
alfuzosin
Uroxatral
Alfuzosin is a medicine that helps men with enlarged prostate glands.
Compare with tamsulosin →
bethanechol
Urecholine
Bethanechol helps you to urinate if you have trouble emptying your bladder.
Compare with tamsulosin →
darifenacin
Enablex
Darifenacin (Enablex) is a medicine that helps control an overactive bladder.
Compare with tamsulosin →
dutasteride
Avodart
Dutasteride and tamsulosin hydrochloride capsules contain two medicines to treat enlarged prostate in men.
Compare with tamsulosin →
dutasteride/tamsulosin
Jalyn
This medicine combines two drugs to treat enlarged prostate in men.
Compare with tamsulosin →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for tamsulosin: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 18,628.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 11.09%.
- fluvoxamine Δ 0.01 pts · 2,289 reports · Selective Serotonin Reuptake Inhibitor (SSRI) 11.10%death share
- clopidogrel Δ 0.01 pts · 192,921 reports · Antiplatelet Agent 11.10%death share
- ascorbic acid Δ 0.05 pts · 22,556 reports · Vitamin C Supplement 11.13%death share
- prasugrel Δ 0.05 pts · 2,254 reports · P2Y12 Inhibitor (Antiplatelet) 11.14%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for tamsulosin
The FDA label for tamsulosin (sold under brand names such as Flomax) classifies it as a prescription-only medication in the Alpha-1 Adrenergic Blocker class. This medicine treats the symptoms of an enlarged prostate, also known as benign prostatic hyperplasia (BPH). Official labeling lists 18 commonly reported side effects, including Headache, Dizziness, Runny nose.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 18,628 voluntary reports. The database also lists 18 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.05 versus $9.35 for the brand - a 99% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC). Shortage status: FDA Drug Shortages Database.
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: January 1, 2026
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages