Hydroxychloroquine vs Azathioprine: side effects in FDA adverse event reports
At a glance
| Hydroxychloroquine | Azathioprine | |
|---|---|---|
| Drug class | – | Purine Antimetabolite |
| Brand names | – | – |
| FAERS reports | 90,536 | 87,582 |
| Serious | 75% | 87% |
| Death outcome | 6,265 | 8,696 |
| Boxed warning | No | Yes - MALIGNANCY Chronic immunosuppression with azathioprine, a purine antimetabolite increases risk of malignancy in humans. Reports of malignancy include post-tra |
Signals both drugs share
| Reaction | Hydroxychloroquine | Azathioprine | Label screen (A / B) |
|---|---|---|---|
| Rheumatic fever | 2,381 · PRR 280.5 | 871 · PRR 59.5 | Likely indication confounding / Likely indication confounding |
| Bone erosion | 1,129 · PRR 108.4 | 814 · PRR 71.4 | Not in label — unassessed / Not in label — unassessed |
| Facet joint syndrome | 1,242 · PRR 151.1 | 644 · PRR 61.4 | Not in label — unassessed / Not in label — unassessed |
| Deep vein thrombosis postoperative | 1,022 · PRR 254.3 | 413 · PRR 63.8 | Not in label — unassessed / Not in label — unassessed |
| Dislocation of vertebra | 854 · PRR 144.7 | 421 · PRR 55.8 | Not in label — unassessed / Not in label — unassessed |
| Adjustment disorder with depressed mood | 787 · PRR 148.8 | 404 · PRR 59.9 | Not in label — unassessed / Not in label — unassessed |
| Lupus vulgaris | 626 · PRR 259.4 | 437 · PRR 139.3 | Not in label — unassessed / Not in label — unassessed |
| Retinitis | 537 · PRR 109.9 | 491 · PRR 99.8 | Not in label — unassessed / Not in label — unassessed |
| Granuloma skin | 364 · PRR 182.4 | 181 · PRR 66.8 | Not in label — unassessed / Not in label — unassessed |
| Grip strength | 111 · PRR 214.0 | 119 · PRR 254.5 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Hydroxychloroquine
- Glossodynia — n=6,867, PRR 102.8 Labeled (related wording)
- Muscle injury — n=3,019, PRR 135.1 Labeled (related wording)
- Sleep disorder due to general medical condition, insomnia type — n=2,401, PRR 138.1 Labeled (related wording)
Labeled signals distinctive to Azathioprine
- Hepatosplenic t-cell lymphoma — n=155, PRR 171.2 Labeled — boxed warning
- Cholestasis of pregnancy — n=100, PRR 67.0 Labeled adverse reaction
- Lung transplant rejection — n=93, PRR 38.8 Labeled (related wording)
Common questions
Which has more reported side effects, Hydroxychloroquine or Azathioprine?
Hydroxychloroquine has 90,536 FAERS reports and Azathioprine 87,582. 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 (75% vs 87%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Hydroxychloroquine and Azathioprine share?
Both drugs carry disproportionality signals for rheumatic fever, bone erosion, facet joint syndrome, deep vein thrombosis postoperative, dislocation of vertebra. Shared signals often reflect a shared drug class or the condition both are used for.
Is Hydroxychloroquine or Azathioprine 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.