Warfarin vs Apixaban: side effects in FDA adverse event reports
At a glance
| Warfarin | Apixaban | |
|---|---|---|
| Drug class | – | Factor Xa Inhibitor |
| Brand names | Warfarin Sodium | – |
| FAERS reports | 126,271 | 66,516 |
| Serious | 80% | 96% |
| Death outcome | 16,103 | 7,220 |
| 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 WARNING: (A) PREMATURE DISCONTINUATION OF APIXABAN INCREASES THE RISK OF THROMBOTIC EVENTS (B) SPINAL/EPIDURAL HEMATOMA (A) PREMATURE DISCONTINUATION OF APIXABA |
Signals both drugs share
No strong shared signal after removing coding and lab terms.
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 Apixaban
- Pericardial haemorrhage — n=220, PRR 35.1 Labeled (related wording)
- Therapeutic drug monitoring analysis not performed — n=48, PRR 60.5 Labeled (related wording)
- Red blood cell transfusion — n=42, PRR 36.9 Labeled (related wording)
Common questions
Which has more reported side effects, Warfarin or Apixaban?
Warfarin has 126,271 FAERS reports and Apixaban 66,516. 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 96%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Warfarin and Apixaban share?
They share no strong flagged signal after artifacts and lab terms are removed.
Is Warfarin or Apixaban 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.