Methotrexate vs Mycophenolate Mofetil: side effects in FDA adverse event reports
At a glance
| Methotrexate | Mycophenolate Mofetil | |
|---|---|---|
| Drug class | – | – |
| Brand names | – | – |
| FAERS reports | 483,097 | 32,904 |
| Serious | 73% | 84% |
| Death outcome | 37,640 | 4,489 |
| Boxed warning | Yes WARNING: EMBRYO-FETAL TOXICITY, HYPERSENSITIVITY REACTIONS, BENZYL ALCOHOL TOXICITY, and OTHER SERIOUS ADVERSE REACTIONS • Methotrexate Injection can cause embr | Yes EMBRYOFETAL TOXICITY, MALIGNANCIES and SERIOUS INFECTIONS Use during pregnancy is associated with increased risks of first trimester pregnancy loss and congenit |
Signals both drugs share
| Reaction | Methotrexate | Mycophenolate Mofetil | Label screen (A / B) |
|---|---|---|---|
| Deep vein thrombosis postoperative | 1,372 · PRR 101.8 | 952 · PRR 147.0 | Not in label — unassessed / Not in label — unassessed |
| Lupus vulgaris | 867 · PRR 117.7 | 530 · PRR 124.9 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Methotrexate
- Pericarditis — n=6,863, PRR 30.0 Labeled adverse reaction
- Duodenal ulcer perforation — n=5,067, PRR 97.3 Labeled (related wording)
- Bone erosion — n=2,084, PRR 61.7 Labeled (related wording)
- Lymphoproliferative disorder — n=1,503, PRR 44.9 Labeled (related wording)
- Rheumatoid lung — n=451, PRR 37.7 Labeled (related wording)
Labeled signals distinctive to Mycophenolate Mofetil
- Post transplant lymphoproliferative disorder — n=2,254, PRR 126.8 Labeled (related wording)
- Polyomavirus-associated nephropathy — n=1,473, PRR 272.3 Labeled adverse reaction
- Bk virus infection — n=1,455, PRR 119.5 Labeled adverse reaction
- Chronic allograft nephropathy — n=435, PRR 192.7 Labeled (related wording)
- Renal transplant failure — n=425, PRR 117.2 Labeled (related wording)
- Graft loss — n=296, PRR 105.1 Labeled adverse reaction
- Lung transplant rejection — n=251, PRR 94.0 Labeled (related wording)
- Human polyomavirus infection — n=227, PRR 120.6 Labeled (related wording)
Common questions
Which has more reported side effects, Methotrexate or Mycophenolate Mofetil?
Methotrexate has 483,097 FAERS reports and Mycophenolate Mofetil 32,904. 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 (73% vs 84%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Methotrexate and Mycophenolate Mofetil share?
Both drugs carry disproportionality signals for deep vein thrombosis postoperative, lupus vulgaris. Shared signals often reflect a shared drug class or the condition both are used for.
Is Methotrexate or Mycophenolate Mofetil 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.