Prednisone vs Leflunomide: side effects in FDA adverse event reports
At a glance
| Prednisone | Leflunomide | |
|---|---|---|
| Drug class | Corticosteroid | Antirheumatic Agent |
| Brand names | – | – |
| FAERS reports | 499,794 | 104,025 |
| Serious | 79% | 82% |
| Death outcome | 52,153 | 9,331 |
| Boxed warning | No | 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
| Reaction | Prednisone | Leflunomide | Label screen (A / B) |
|---|---|---|---|
| Synovitis | 8,900 · PRR 40.3 | 10,363 · PRR 275.3 | Likely indication confounding / Labeled adverse reaction |
| Glossodynia | 8,626 · PRR 25.9 | 8,702 · PRR 128.9 | Not in label — unassessed / Labeled (related wording) |
| Duodenal ulcer perforation | 4,860 · PRR 82.3 | 5,149 · PRR 485.9 | Labeled (related wording) / Not in label — unassessed |
| Rheumatic fever | 3,108 · PRR 104.3 | 3,226 · PRR 587.9 | Likely indication confounding / Labeled (related wording) |
| Peripheral venous disease | 1,457 · PRR 23.7 | 1,527 · PRR 125.1 | Not in label — unassessed / Labeled (related wording) |
| Pemphigus | 9,174 · PRR 119.7 | 9,382 · PRR 642.9 | Likely indication confounding / Not in label — unassessed |
| Hand deformity | 7,949 · PRR 64.7 | 8,389 · PRR 367.0 | Not in label — unassessed / Not in label — unassessed |
| Pericarditis | 6,736 · PRR 28.0 | 6,347 · PRR 124.4 | Not in label — unassessed / Not in label — unassessed |
| Helicobacter infection | 5,030 · PRR 40.4 | 5,181 · PRR 210.1 | Not in label — unassessed / Not in label — unassessed |
| Folliculitis | 4,563 · PRR 32.7 | 4,922 · PRR 184.7 | Not in label — unassessed / Not in label — unassessed |
| Muscle injury | 4,043 · PRR 40.2 | 4,227 · PRR 215.9 | Not in label — unassessed / Not in label — unassessed |
| Sleep disorder due to general medical condition, insomnia type | 3,038 · PRR 37.0 | 3,116 · PRR 190.4 | Not in label — unassessed / Not in label — unassessed |
| Facet joint syndrome | 1,801 · PRR 55.5 | 2,008 · PRR 360.0 | Not in label — unassessed / Not in label — unassessed |
| Bone erosion | 1,189 · PRR 20.8 | 1,595 · PRR 166.0 | Not in label — unassessed / Not in label — unassessed |
| Deep vein thrombosis postoperative | 1,287 · PRR 80.1 | 1,325 · PRR 429.2 | Not in label — unassessed / Not in label — unassessed |
| Dislocation of vertebra | 1,083 · PRR 39.3 | 1,106 · PRR 200.8 | Not in label — unassessed / Not in label — unassessed |
| Adjustment disorder with depressed mood | 1,072 · PRR 47.2 | 1,042 · PRR 217.5 | Not in label — unassessed / Not in label — unassessed |
| Lupus vulgaris | 814 · PRR 91.1 | 781 · PRR 392.3 | Not in label — unassessed / Not in label — unassessed |
| Retinitis | 721 · PRR 31.4 | 683 · PRR 140.1 | Likely indication confounding / Not in label — unassessed |
| Granuloma skin | 482 · PRR 57.9 | 496 · PRR 304.8 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Prednisone
- Nocardiosis — n=888, PRR 21.9 Labeled (related wording)
- Steroid diabetes — n=492, PRR 21.0 Labeled (related wording)
- Secondary immunodeficiency — n=420, PRR 22.4 Labeled (related wording)
Labeled signals distinctive to Leflunomide
- Hepatic enzyme — n=85, PRR 317.4 Labeled (related wording)
Common questions
Which has more reported side effects, Prednisone or Leflunomide?
Prednisone has 499,794 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 (79% vs 82%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Prednisone and Leflunomide share?
Both drugs carry disproportionality signals for synovitis, glossodynia, duodenal ulcer perforation, rheumatic fever, peripheral venous disease. Shared signals often reflect a shared drug class or the condition both are used for.
Is Prednisone 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.