Metformin is the most commonly prescribed oral antidiabetic drug worldwide and the first choice in the treatment of type 2 diabetes. It belongs to the group of biguanides and lowers blood sugar levels without increasing the risk of hypoglycemia when used alone.
Mode of action
Metformin intervenes in glucose metabolism at several points:
- Inhibition of glucose production in the liver (gluconeogenesis)
- Improving insulin sensitivity in muscle and fat tissue
- Delay in carbohydrate absorption from the intestine
Advantages
- No risk of hypoglycemia with monotherapy
- Slight weight-reducing effect
- Positive effects on cardiovascular risk
- Favorable price-performance ratio
Application and tolerance
Metformin is tapered slowly to minimize gastrointestinal side effects (nausea, diarrhea, bloating). It is always taken with or after meals.
Contraindications
Metformin must not be used in:
- Severe renal insufficiency (eGFR < 30 ml/min)
- Severe liver disease
- Acute dehydration or severe infection
- 48 hours before and after examinations with iodinated contrast medium
Further information:
→ Diabetes mellitus – knowledge and overview
→ Why hyporest
→ Type 2 diabetes
Sources
- German Diabetes Society (DDG). S3 guideline “Type 2 diabetes”. As of 2025. Available at: www.deutsche-diabetes-gesellschaft.de/leitlinien.
- American Diabetes Association. Standards of Medical Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1). Available at: diabetesjournals.org.
- Robert Koch Institute (RKI). Federal health reporting – diabetes mellitus in Germany. Berlin 2024.
- International Diabetes Federation (IDF). IDF Diabetes Atlas. 11th edition. Brussels 2025. Available at: diabetesatlas.org.
Important note:
The information in this encyclopedia article is intended solely for general and non-binding information. They do not replace medical advice, diagnosis or therapy. If you have any health questions or complaints, please always consult a doctor or qualified healthcare professional. The content was created with the greatest possible care, but errors cannot be completely ruled out.
Last updated: February 26, 2026
