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heparin Side Effects

Also known as: Heparin Sodium

Analysis of 12,966 adverse event reports submitted to the FDA from 2004 to 2025.

Total Reports

12,966

Death-Related

2,519

19.4% of reports

Hospitalizations

5,169

39.9% of reports

Top Indication

Product Used For Unknown Indication

Most Reported Adverse Reactions

HEPARIN-INDUCED THROMBOCYTOPENIA
1,207
DRUG INEFFECTIVE
924
NAUSEA
708
OFF LABEL USE
697
DRUG HYPERSENSITIVITY
603
VOMITING
572
HYPOTENSION
547
DYSPNOEA
519
PYREXIA
465
THROMBOCYTOPENIA
458
PULMONARY EMBOLISM
457
SEPSIS
452
ABDOMINAL PAIN
449
ANAEMIA
440
THROMBOSIS
406
CONDITION AGGRAVATED
368
DEATH
364
DIARRHOEA
361
CONSTIPATION
355
PNEUMONIA
350

Who Reports Side Effects

Gender Distribution

Female 4,912 (45%)
Male 5,808 (53%)
Unknown 148

Age Distribution

0-17 703 (8%)
18-44 1,433 (15%)
45-64 2,924 (31%)
65-74 2,249 (24%)
75+ 2,053 (22%)

Reporting Trend by Year

2004 2025

Reactions in Death Reports

Top reactions reported in 2,519 reports where death was an outcome. These are voluntarily reported and do not establish causation.

Reaction Reports
DEATH 364
SEPSIS 339
MULTIPLE ORGAN DYSFUNCTION SYNDROME 309
VOMITING 279
NAUSEA 277
GENERAL PHYSICAL HEALTH DETERIORATION 266
OFF LABEL USE 264
HEPARIN-INDUCED THROMBOCYTOPENIA 254
CARDIOGENIC SHOCK 240
ABDOMINAL PAIN 239
HYPONATRAEMIA 233
CONSTIPATION 227
STRESS 227
ASCITES 224
PULMONARY EMBOLISM 216
ABDOMINAL DISTENSION 215
APPENDICITIS 209
APPENDICOLITH 206
VENTRICULAR FIBRILLATION 198
CONDITION AGGRAVATED 197

Reactions in Hospitalization Reports

Top reactions in 5,169 reports where hospitalization was an outcome.

Reaction Reports
HEPARIN-INDUCED THROMBOCYTOPENIA 565
PYREXIA 329
NAUSEA 308
ANAEMIA 294
VOMITING 287
OFF LABEL USE 284
DRUG INEFFECTIVE 283
PULMONARY EMBOLISM 277
DYSPNOEA 269
SEPSIS 256
PNEUMONIA 253
CONDITION AGGRAVATED 230
DIARRHOEA 220
THROMBOSIS 213
ABDOMINAL PAIN 212
THROMBOCYTOPENIA 212
FEBRILE NEUTROPENIA 204
HYPOTENSION 201
CONSTIPATION 190
HAEMOGLOBIN DECREASED 189

Nearby — Related Medications

Compare heparin vs apixaban →

What the FAERS Data Reveals About heparin Side Effects

The FDA Adverse Event Reporting System (FAERS) contains 12,966 voluntary reports linked to heparin and its brand equivalents (Heparin Sodium), spanning 2004 through 2025. Of those, 2,519 (19.4%) listed death as an outcome and 5,169 (39.9%) 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, 45% were female and 53% male; age distribution skews toward 45-64, with 2,924 reports in that bracket. The single most reported reaction is heparin-induced thrombocytopenia with 1,207 submissions, followed by drug ineffective and nausea.

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.