Warfarin vs Enoxaparin: side effects in FDA adverse event reports
At a glance
| Warfarin | Enoxaparin | |
|---|---|---|
| Drug class | – | – |
| Brand names | Warfarin Sodium | Enoxaparin Sodium |
| FAERS reports | 126,271 | 57,199 |
| Serious | 80% | 87% |
| Death outcome | 16,103 | 8,879 |
| Boxed warning | Yes BLEEDING RISK Warfarin sodium can cause major or fatal bleeding [see Warnings and Precautions (5.1) ] . Perform regular monitoring of INR in all treated patient | Yes SPINAL/EPIDURAL HEMATOMAS Epidural or spinal hematomas may occur in patients who are anticoagulated with low molecular weight heparins (LMWH) or heparinoids and |
Signals both drugs share
| Reaction | Warfarin | Enoxaparin | Label screen (A / B) |
|---|---|---|---|
| Retroperitoneal haemorrhage | 261 · PRR 19.5 | 341 · PRR 58.6 | Not in label — unassessed / Labeled (related wording) |
| Retroperitoneal haematoma | 268 · PRR 23.0 | 286 · PRR 54.8 | Not in label — unassessed / Labeled (related wording) |
| Abdominal wall haematoma | 285 · PRR 28.4 | 258 · PRR 56.0 | Not in label — unassessed / Labeled (related wording) |
| Peritoneal haemorrhage | 101 · PRR 12.8 | 68 · PRR 18.6 | Not in label — unassessed / Labeled (related wording) |
| Muscle haemorrhage | 305 · PRR 13.6 | 268 · PRR 26.2 | Not in label — unassessed / Not in label — unassessed |
| Intra-abdominal haematoma | 135 · PRR 20.1 | 153 · PRR 51.4 | Not in label — unassessed / Not in label — unassessed |
| Haematoma muscle | 101 · PRR 15.5 | 159 · PRR 57.2 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Warfarin
- Calciphylaxis — n=729, PRR 110.2 Labeled — boxed warning
- Vascular calcification — n=134, PRR 23.6 Labeled (related wording)
- Catheter site pruritus — n=84, PRR 17.5 Labeled (related wording)
Labeled signals distinctive to Enoxaparin
- Haematoma — n=1,109, PRR 16.3 Labeled — boxed warning
- Hepatocellular injury — n=656, PRR 17.7 Labeled (related wording)
- Heparin-induced thrombocytopenia — n=637, PRR 54.1 Labeled — boxed warning
- Eosinophilia — n=621, PRR 13.5 Labeled adverse reaction
- Shock haemorrhagic — n=549, PRR 26.5 Labeled (related wording)
- Haemorrhagic stroke — n=405, PRR 19.9 Labeled adverse reaction
- Vascular purpura — n=73, PRR 20.3 Labeled (related wording)
- Arterial haemorrhage — n=49, PRR 16.3 Labeled (related wording)
Common questions
Which has more reported side effects, Warfarin or Enoxaparin?
Warfarin has 126,271 FAERS reports and Enoxaparin 57,199. More reports does not mean more dangerous: volume follows how widely and how long a drug has been used, prescription vs over-the-counter status, and publicity. The seriousness share (80% vs 87%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Warfarin and Enoxaparin share?
Both drugs carry disproportionality signals for retroperitoneal haemorrhage, retroperitoneal haematoma, abdominal wall haematoma, peritoneal haemorrhage, muscle haemorrhage. Shared signals often reflect a shared drug class or the condition both are used for.
Is Warfarin or Enoxaparin safer?
FAERS cannot answer that: it has no denominator and no comparator. Use this page to see which risks are already on each label and which signals are unlabeled, then check the prescribing information and your clinician for your situation.
Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, openFDA count queries for seriousness and deaths. Pair chosen because it is a commonly searched comparison. Generated 2026-10-08.