What happens if you stop taking metformin
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Effects of Stopping Metformin: A Comprehensive Overview
Introduction to Metformin and Its Use in Diabetes Management
Metformin is a widely prescribed medication for managing type 2 diabetes mellitus (T2DM). It is known for its efficacy in lowering blood glucose levels and improving metabolic parameters. However, patients may need to discontinue metformin for various reasons, including side effects, contraindications, or changes in renal function. This article explores the consequences of stopping metformin based on recent research findings.
Impact on Glycemic Control
Increased Hemoglobin A1c and Blood Glucose Levels
One of the most immediate effects of stopping metformin is a deterioration in glycemic control. Studies have shown that patients who discontinue metformin experience significant increases in hemoglobin A1c (HbA1c) levels and fasting blood glucose (FBG) . This deterioration can be rapid and severe, particularly in individuals who had poor glycemic control before starting metformin.
Reversible Effects on Diabetes Risk
In the Diabetes Prevention Program (DPP), it was observed that the risk of developing diabetes increased after stopping metformin, although some of the protective effects persisted. Specifically, the incidence of diabetes was still reduced by 25% even after a short washout period, indicating that some benefits of metformin are sustained beyond its pharmacological action.
Effects on Body Weight and Metabolic Parameters
Weight Gain After Discontinuation
Metformin is known to aid in weight loss and improve metabolic profiles. However, these benefits are often lost upon discontinuation. Research involving patients with schizophrenia treated with clozapine showed that the weight reduction achieved with metformin was reversed after stopping the medication. Similar trends were observed in diabetic patients, where discontinuation led to an increase in body mass index (BMI).
Changes in Gut Hormones and Microbiota
Metformin has complex effects on gut hormones and microbiota, which contribute to its glucose-lowering effects. Upon stopping metformin, there is a reduction in active and total glucagon-like peptide-1 (GLP-1) and an elevation in serum bile acids. These changes are associated with a rise in blood glucose levels and a reversal of the beneficial gut microbiota alterations induced by metformin.
Cardiovascular and Renal Outcomes
Increased Cardiovascular and Renal Risks
Discontinuing metformin in patients with advanced chronic kidney disease (CKD) has been associated with increased risks of major adverse cardiovascular events (MACE), heart failure, end-stage kidney disease (ESKD), and mortality. A large cohort study found that patients who stopped metformin had higher rates of these adverse outcomes compared to those who continued the medication, even when renal function was significantly impaired.
No Increase in Lactic Acidosis
Despite concerns about lactic acidosis, studies have shown that stopping metformin does not necessarily lead to an increase in lactic acid levels. In fact, no cases of lactic acidosis were reported in a study where patients with mild renal impairment continued metformin.
Conclusion
Stopping metformin can lead to significant negative outcomes, including worsened glycemic control, weight gain, and increased cardiovascular and renal risks. While some benefits of metformin may persist after discontinuation, the overall impact is generally detrimental. Therefore, it is crucial for healthcare providers to carefully weigh the risks and benefits before advising patients to stop metformin, especially in those with advanced CKD or other contraindications.
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