Metformin and weight gain
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Metformin and Weight Gain: A Comprehensive Review
Introduction to Metformin and Weight Management
Metformin, a widely used antihyperglycemic agent, has been extensively studied for its effects on weight management, particularly in patients experiencing weight gain due to various medical treatments and conditions. This article synthesizes findings from multiple studies to provide a clear understanding of metformin's role in mitigating weight gain.
Metformin and Antipsychotic-Induced Weight Gain
Efficacy in Children and Adolescents
Second-generation antipsychotics (SGAs) are known to cause significant weight gain in children and adolescents. A 16-week double-blind, placebo-controlled trial demonstrated that metformin effectively stabilized weight in young patients who had gained more than 10% of their body weight due to antipsychotic therapy. The study found that metformin not only prevented further weight gain but also improved insulin sensitivity and glucose metabolism without serious adverse effects.
Systematic Reviews and Meta-Analyses
A systematic review and meta-analysis of randomized controlled trials (RCTs) further confirmed the efficacy of metformin in managing weight gain in children and adolescents treated with SGAs. The analysis showed significant weight reduction at 4, 12, and 16 weeks of treatment, with parallel decreases in body mass index (BMI). Another meta-analysis supported these findings, highlighting a significant reduction in weight and BMI z-scores after 12-16 weeks of metformin therapy.
First-Episode Schizophrenia Patients
In drug-naive first-episode schizophrenia patients, a double-blind, placebo-controlled study found that metformin significantly attenuated olanzapine-induced weight gain. Patients treated with metformin experienced less increase in weight, BMI, and waist circumference compared to those receiving a placebo. Additionally, metformin helped maintain stable insulin and insulin resistance index levels.
Metformin in Type 2 Diabetes and Obesity
Long-Term Effects in Type 2 Diabetes
Metformin has been shown to prevent weight gain in patients with type 2 diabetes (T2D). A post hoc analysis of a 4.3-year trial revealed that metformin users had significantly less weight gain compared to placebo users, despite no significant differences in energy intake between the groups. This suggests that metformin's weight-sparing effects are not due to reduced caloric intake.
Broader Implications for Obesity
A comprehensive review of metformin's effects on body weight across various patient populations, including those with T2D, antipsychotic-induced weight gain, and obesity, indicated that metformin consistently mitigates weight gain. The maximal effect of metformin on weight reduction was observed in patients with antipsychotic-induced weight gain, followed by those with T2D and obesity.
Combination Therapies
Metformin and Lifestyle Interventions
Combining metformin with lifestyle interventions has shown promising results in reducing antipsychotic-related weight gain. A meta-analysis of RCTs found that the combination of metformin and lifestyle changes led to significant reductions in weight and BMI compared to metformin or lifestyle interventions alone. This combination also resulted in fewer instances of clinically significant weight gain.
Conclusion
Metformin is a valuable tool in managing weight gain associated with various medical treatments and conditions. Its efficacy in stabilizing weight, improving insulin sensitivity, and reducing BMI has been consistently demonstrated across multiple studies. While metformin alone is effective, combining it with lifestyle interventions may offer additional benefits. Further high-quality research is needed to confirm these findings and optimize treatment protocols.
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