Metformin vs Sitagliptin: side effects in FDA adverse event reports
At a glance
| Metformin | Sitagliptin | |
|---|---|---|
| Drug class | – | – |
| Brand names | Metformin Hydrochloride | – |
| FAERS reports | 354,745 | 71,655 |
| Serious | 69% | 64% |
| Death outcome | 29,950 | 6,770 |
| Boxed warning | Yes LACTIC ACIDOSIS Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Th | No |
Signals both drugs share
| Reaction | Metformin | Sitagliptin | Label screen (A / B) |
|---|---|---|---|
| Diabetes mellitus inadequate control | 2,895 · PRR 11.4 | 1,070 · PRR 18.8 | Labeled (related wording) / Labeled (related wording) |
| Euglycaemic diabetic ketoacidosis | 1,754 · PRR 46.1 | 246 · PRR 19.2 | Labeled (related wording) / Likely indication confounding |
| Adjustment disorder | 301 · PRR 17.5 | 278 · PRR 79.2 | Not in label — unassessed / Labeled (related wording) |
| Pancreatic carcinoma metastatic | 287 · PRR 6.5 | 531 · PRR 66.8 | Not in label — unassessed / Likely indication confounding |
| Nephrogenic anaemia | 536 · PRR 7.5 | 241 · PRR 15.9 | Not in label — unassessed / Not in label — unassessed |
| Personality disorder | 345 · PRR 8.8 | 301 · PRR 37.6 | Not in label — unassessed / Not in label — unassessed |
| Carotid artery thrombosis | 296 · PRR 31.0 | 285 · PRR 147.0 | Not in label — unassessed / Not in label — unassessed |
| Neurologic neglect syndrome | 289 · PRR 62.7 | 278 · PRR 290.9 | Not in label — unassessed / Not in label — unassessed |
| Hyperparathyroidism secondary | 295 · PRR 7.7 | 103 · PRR 12.4 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Metformin
- Acute kidney injury — n=17,231, PRR 7.4 Labeled — boxed warning
- Lactic acidosis — n=17,141, PRR 67.6 Labeled — boxed warning
- Hypoglycaemia — n=7,287, PRR 10.3 Labeled — boxed warning
- Metabolic acidosis — n=6,200, PRR 14.2 Labeled adverse reaction
- Diabetic ketoacidosis — n=4,053, PRR 11.9 Labeled adverse reaction
- Ketoacidosis — n=1,347, PRR 12.8 Labeled adverse reaction
- Vitamin b12 deficiency — n=630, PRR 10.8 Labeled (related wording)
- Diabetic metabolic decompensation — n=469, PRR 29.9 Labeled (related wording)
Labeled signals distinctive to Sitagliptin
- Pemphigoid — n=311, PRR 12.8 Labeled adverse reaction
- Insulin-requiring type 2 diabetes mellitus — n=47, PRR 51.8 Labeled (related wording)
Common questions
Which has more reported side effects, Metformin or Sitagliptin?
Metformin has 354,745 FAERS reports and Sitagliptin 71,655. 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 (69% vs 64%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Metformin and Sitagliptin share?
Both drugs carry disproportionality signals for diabetes mellitus inadequate control, euglycaemic diabetic ketoacidosis, adjustment disorder, pancreatic carcinoma metastatic, nephrogenic anaemia. Shared signals often reflect a shared drug class or the condition both are used for.
Is Metformin or Sitagliptin 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.