Metformin: Side Effects, Uses & Monitoring
Metformin hydrochloride extended-release tablets are indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus.
- Data source
- FDA labeling via NIH DailyMed (label 1ebaab3a…)
- Label version
- current
- Last reviewed
- 2026
Reported adverse reactions
Reactions listed in current FDA labeling, with the highest frequency reported across summarized placebo-controlled trials.
| Adverse reaction (as reported in labeling) | Reported frequency* |
|---|---|
| Diarrhea | 53% |
| Nausea/vomiting | 26% |
| Flatulence | 12% |
| Asthenia | 9% |
| Indigestion | 7% |
| Abdominal discomfort | 6% |
| Headache | 6% |
*Highest percentage reported for the active moiety across placebo-controlled trial tables in current FDA labeling. Values reflect trial reporting, not your individual risk.
Labeled uses (from FDA prescribing information)
Metformin hydrochloride extended-release tablets are indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus.
Tests providers may use to monitor Metformin therapy
Comprehensive Metabolic Panel (CMP)
Measures 14 substances in the blood to assess kidney and liver function, electrolyte balance, and blood sugar ...
Hemoglobin A1c (HbA1c)
Reflects average blood sugar over the past 2-3 months....
Vitamin B12
Detects B12 deficiency which can cause anemia and neurological symptoms....
Conditions associated with Metformin in labeling
Frequently Asked Questions
What is Metformin used for?
FDA labeling lists the approved uses shown above under "Labeled uses." This summary is informational; only a qualified prescriber can determine whether a medication is appropriate for you.
What are the most commonly reported side effects of Metformin?
The table above shows adverse reactions and the highest frequencies reported in placebo-controlled trials summarized in current FDA labeling for Metformin. Individual risk varies.
Does Metformin require lab monitoring?
Labeling and standard practice associate Metformin with periodic laboratory monitoring; the tests above are commonly ordered by clinicians to monitor patients on therapy. Your provider decides what is appropriate.
Where does this information come from?
All clinical facts on this page were extracted from the current FDA-registered product labeling for this ingredient, published by manufacturers through NIH DailyMed. See the source link below.
Medical disclaimer: Educational content extracted from public FDA labeling. Not medical advice. Always consult a qualified healthcare professional before starting, stopping, or changing any medication.