Lenalidomide vs Leflunomide: side effects in FDA adverse event reports
At a glance
| Lenalidomide | Leflunomide | |
|---|---|---|
| Drug class | Thalidomide Analog | Antirheumatic Agent |
| Brand names | – | – |
| FAERS reports | 419,568 | 104,025 |
| Serious | 64% | 82% |
| Death outcome | 53,763 | 9,331 |
| Boxed warning | Yes EMBRYO-FETAL TOXICITY, HEMATOLOGIC TOXICITY, and VENOUS and ARTERIAL THROMBOEMBOLISM Embryo-Fetal Toxicity Do not use lenalidomide capsules during pregnancy. Le | Yes EMBRYO-FETAL TOXICITY and HEPATOTOXICITY WARNING: EMBRYO-FETAL TOXICITY and HEPATOTOXICITY Embryo-Fetal Toxicity Leflunomide is contraindicated for use in pregn |
Signals both drugs share
No strong shared signal after removing coding and lab terms.
Labeled signals distinctive to Lenalidomide
- Plasma cell myeloma — n=17,121, PRR 38.5 Labeled (related wording)
- Neuropathy peripheral — n=12,164, PRR 7.2 Labeled adverse reaction
- Multiple myeloma — n=2,370, PRR 49.7 Labeled — boxed warning
- Myelodysplastic syndrome — n=2,154, PRR 8.6 Labeled — boxed warning
- Cytopenia — n=1,476, PRR 6.9 Labeled — boxed warning
- Squamous cell carcinoma of skin — n=761, PRR 7.1 Labeled adverse reaction
- Plasma cell myeloma refractory — n=625, PRR 46.1 Labeled (related wording)
- Plasma cell leukaemia — n=313, PRR 54.3 Labeled (related wording)
Labeled signals distinctive to Leflunomide
- Synovitis — n=10,363, PRR 275.3 Labeled adverse reaction
- Glossodynia — n=8,702, PRR 128.9 Labeled (related wording)
- Rheumatic fever — n=3,226, PRR 587.9 Labeled (related wording)
- Peripheral venous disease — n=1,527, PRR 125.1 Labeled (related wording)
- Hepatic enzyme — n=85, PRR 317.4 Labeled (related wording)
Common questions
Which has more reported side effects, Lenalidomide or Leflunomide?
Lenalidomide has 419,568 FAERS reports and Leflunomide 104,025. 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 (64% vs 82%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Lenalidomide and Leflunomide share?
They share no strong flagged signal after artifacts and lab terms are removed.
Is Lenalidomide or Leflunomide 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.