Contraindications for metformin
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Key Contraindications for Metformin Use
Metformin is widely used as a first-line treatment for type 2 diabetes, but there are important contraindications that must be considered to ensure patient safety. The most significant contraindications are related to the risk of lactic acidosis and the presence of severe chronic diseases affecting the kidneys, liver, or heart 124610.
Renal Impairment and Metformin Contraindication
Severe renal impairment is a primary contraindication for metformin use. Specifically, metformin should not be used in patients with an estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m² 26. This is because reduced kidney function increases the risk of metformin accumulation and lactic acidosis. For patients with mild to moderate kidney dysfunction (eGFR 30–60 mL/min/1.73 m²), metformin can be used with caution and dose adjustment 268. Regular monitoring of renal function is essential, especially in elderly patients or those with fluctuating kidney function 5910.
Hepatic Disease and Metformin Use
Active or progressive severe liver disease is another contraindication for metformin. Liver dysfunction can impair lactate clearance, increasing the risk of lactic acidosis 126. Patients with chronic liver disease and impaired hepatic function should generally avoid metformin 6810.
Cardiac Failure and Hemodynamic Instability
Metformin is contraindicated in patients with unstable or acute heart failure, as well as those with hypoperfusion or hemodynamic instability 126. However, recent evidence suggests that metformin may be safe in patients with compensated or stable heart failure, and the FDA has relaxed previous restrictions in this group 3678.
Acute Complications and Other Conditions
Metformin should not be used during acute complications of diabetes, such as diabetic ketoacidosis or hyperosmolar states . Other contraindications include active alcohol abuse, a history of lactic acidosis, and severe acute illness that may increase the risk of hypoxia or impaired drug clearance 2410.
Age and Multiple Comorbidities
While advanced age alone is no longer considered a strict contraindication, caution is advised in elderly patients, especially those with multiple comorbidities or declining organ function. The decision to use metformin should be based on individual assessment of renal and hepatic function rather than age alone 357.
Conclusion
Metformin remains a cornerstone of type 2 diabetes management, but its use is contraindicated in patients with severe renal impairment (eGFR <30 mL/min/1.73 m²), severe liver disease, unstable heart failure, acute diabetic complications, and certain acute illnesses. Careful patient selection and regular monitoring of kidney and liver function are essential to minimize risks and ensure safe use of metformin in clinical practice 12345678+2 MORE.
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