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tamsulosin Side Effects

Also known as: Flomax

Analysis of 18,628 adverse event reports submitted to the FDA from 2004 to 2025.

Total Reports

18,628

Death-Related

2,065

11.1% of reports

Hospitalizations

6,635

35.6% of reports

Top Indication

Product Used For Unknown Indication

Most Reported Adverse Reactions

FATIGUE
1,417
DYSPNOEA
1,332
DIZZINESS
1,131
DIARRHOEA
1,121
OFF LABEL USE
961
DRUG INEFFECTIVE
911
HEADACHE
883
ASTHENIA
842
FALL
839
NAUSEA
808
COUGH
711
MALAISE
652
PRURITUS
651
ARTHRALGIA
644
DEATH
639
DECREASED APPETITE
601
PYREXIA
586
PAIN
559
PAIN IN EXTREMITY
557
SOMNOLENCE
543

Who Reports Side Effects

Gender Distribution

Female 816 (5%)
Male 15,913 (95%)
Unknown 12

Age Distribution

0-17 55 (0%)
18-44 261 (2%)
45-64 2,671 (21%)
65-74 4,228 (33%)
75+ 5,689 (44%)

Reporting Trend by Year

2004 2025

Reactions in Death Reports

Top reactions reported in 2,065 reports where death was an outcome. These are voluntarily reported and do not establish causation.

Reaction Reports
DEATH 638
DYSPNOEA 308
SEPSIS 295
CARDIO-RESPIRATORY ARREST 279
DIARRHOEA 276
FALL 273
HAEMORRHAGIC STROKE 265
DIZZINESS 255
ALTERED STATE OF CONSCIOUSNESS 248
FATIGUE 232
HEADACHE 231
DECREASED APPETITE 225
MALAISE 224
ASTHENIA 216
TACHYCARDIA 212
CHILLS 211
ASCITES 209
INSOMNIA 209
ABDOMINAL PAIN 208
PYREXIA 208

Reactions in Hospitalization Reports

Top reactions in 6,635 reports where hospitalization was an outcome.

Reaction Reports
DYSPNOEA 623
PNEUMONIA 435
FALL 380
DIZZINESS 351
FATIGUE 345
DIARRHOEA 343
OFF LABEL USE 336
HYPOTENSION 320
ASTHENIA 296
ASTHMA 272
ACUTE KIDNEY INJURY 256
HYPERTENSION 254
PYREXIA 251
WHEEZING 244
ATRIAL FIBRILLATION 241
PRODUCTIVE COUGH 238
URINARY TRACT INFECTION 232
ANAEMIA 229
BENIGN PROSTATIC HYPERPLASIA 227
NAUSEA 223

Nearby — Related Medications

Compare tamsulosin vs alfuzosin →

What the FAERS Data Reveals About tamsulosin Side Effects

The FDA Adverse Event Reporting System (FAERS) contains 18,628 voluntary reports linked to tamsulosin and its brand equivalents (Flomax), spanning 2004 through 2025. Of those, 2,065 (11.1%) listed death as an outcome and 6,635 (35.6%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.

Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 5% were female and 95% male; age distribution skews toward 75+, with 5,689 reports in that bracket. The single most reported reaction is fatigue with 1,417 submissions, followed by dyspnoea and dizziness.

FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice — speak with a licensed clinician about any side-effect concerns.