Sulfasalazine vs Mesalamine: side effects in FDA adverse event reports
At a glance
| Sulfasalazine | Mesalamine | |
|---|---|---|
| Drug class | Aminosalicylate | Aminosalicylate |
| Brand names | – | – |
| FAERS reports | 77,779 | 55,824 |
| Serious | 84% | 75% |
| Death outcome | 7,233 | 2,749 |
| Boxed warning | No | No |
Signals both drugs share
| Reaction | Sulfasalazine | Mesalamine | Label screen (A / B) |
|---|---|---|---|
| Subcutaneous drug absorption impaired | 228 · PRR 194.9 | 50 · PRR 37.9 | Labeled (related wording) / Not in label — unassessed |
| Deep vein thrombosis postoperative | 1,252 · PRR 485.1 | 276 · PRR 61.5 | Not in label — unassessed / Not in label — unassessed |
| Dislocation of vertebra | 1,073 · PRR 253.2 | 270 · PRR 51.8 | Not in label — unassessed / Not in label — unassessed |
| Adjustment disorder with depressed mood | 969 · PRR 251.5 | 267 · PRR 57.3 | Not in label — unassessed / Not in label — unassessed |
| Lupus vulgaris | 844 · PRR 675.8 | 281 · PRR 116.2 | Not in label — unassessed / Not in label — unassessed |
| Retinitis | 743 · PRR 217.6 | 290 · PRR 78.9 | Not in label — unassessed / Not in label — unassessed |
| Seronegative arthritis | 483 · PRR 204.8 | 155 · PRR 60.1 | Likely indication confounding / Not in label — unassessed |
| Grip strength | 123 · PRR 307.5 | 106 · PRR 318.5 | Not in label — unassessed / Not in label — unassessed |
| Swollen joint count | 135 · PRR 331.3 | 53 · PRR 103.1 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Sulfasalazine
- Pericarditis — n=5,998, PRR 152.1 Labeled adverse reaction
Labeled signals distinctive to Mesalamine
- Rectal tenesmus — n=120, PRR 40.5 Labeled (related wording)
Common questions
Which has more reported side effects, Sulfasalazine or Mesalamine?
Sulfasalazine has 77,779 FAERS reports and Mesalamine 55,824. 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 (84% vs 75%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Sulfasalazine and Mesalamine share?
Both drugs carry disproportionality signals for subcutaneous drug absorption impaired, deep vein thrombosis postoperative, dislocation of vertebra, adjustment disorder with depressed mood, lupus vulgaris. Shared signals often reflect a shared drug class or the condition both are used for.
Is Sulfasalazine or Mesalamine 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.