Allopurinol vs Colchicine: side effects in FDA adverse event reports
At a glance
| Allopurinol | Colchicine | |
|---|---|---|
| Drug class | Xanthine Oxidase Inhibitor | Alkaloid |
| Brand names | – | – |
| FAERS reports | 155,426 | 26,169 |
| Serious | 82% | 81% |
| Death outcome | 21,873 | 3,239 |
| Boxed warning | No | No |
Signals both drugs share
| Reaction | Allopurinol | Colchicine | Label screen (A / B) |
|---|---|---|---|
| Gout | 2,255 · PRR 19.2 | 1,122 · PRR 53.3 | Likely indication confounding / Likely indication confounding |
| Hyperparathyroidism secondary | 358 · PRR 22.1 | 86 · PRR 28.1 | Not in label — unassessed / Not in label — unassessed |
| Chronic kidney disease-mineral and bone disorder | 140 · PRR 20.1 | 41 · PRR 31.7 | Not in label — unassessed / Not in label — unassessed |
| Gouty arthritis | 111 · PRR 21.7 | 54 · PRR 58.2 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Allopurinol
- Drug reaction with eosinophilia and systemic symptoms — n=2,952, PRR 17.5 Labeled adverse reaction
- Toxic epidermal necrolysis — n=1,170, PRR 11.3 Labeled adverse reaction
- End stage renal disease — n=1,153, PRR 8.9 Labeled (related wording)
- Stevens-johnson syndrome — n=1,112, PRR 7.0 Labeled adverse reaction
- Tumour lysis syndrome — n=860, PRR 14.6 Labeled adverse reaction
- Drug rash with eosinophilia and systemic symptoms — n=280, PRR 12.5 Labeled (related wording)
- Dermatitis exfoliative generalised — n=235, PRR 9.8 Labeled (related wording)
- Tumour flare — n=114, PRR 26.9 Labeled (related wording)
Labeled signals distinctive to Colchicine
- Drug tolerance decreased — n=94, PRR 27.8 Labeled (related wording)
- Myopathy toxic — n=46, PRR 66.9 Labeled (related wording)
- Central nervous system lupus — n=42, PRR 192.7 Labeled (related wording)
Common questions
Which has more reported side effects, Allopurinol or Colchicine?
Allopurinol has 155,426 FAERS reports and Colchicine 26,169. 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 (82% vs 81%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Allopurinol and Colchicine share?
Both drugs carry disproportionality signals for gout, hyperparathyroidism secondary, chronic kidney disease-mineral and bone disorder, gouty arthritis. Shared signals often reflect a shared drug class or the condition both are used for.
Is Allopurinol or Colchicine 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.