Metformin Contraindications

NewsGuard 100/100 Score

The biguanide metformin (dimethylbiguanide) was initially introduced for the treatment of type 2 diabetes mellitus in the late 1950s. Today, this drug is considered to be the first-choice agent and the “gold standard” for most people with type 2 diabetes. It has been estimated that the annual number of people receiving prescriptions for metformin worldwide is more than 120 million.

The efficacy and benefits of metformin treatment in type 2 diabetes have been confirmed by large-scale studies and recognized by many consensus statements. Still, a large list of contraindications may increase the incidence of serious adverse effects, which precludes many patients from taking metformin.

Image Credit: Anastasiya Artcomma / Shutterstock.com

Intolerance and contraindications to metformin

Three particular contraindications to the use of metformin have been suggested. These include renal impairment with elevated serum creatine levels (i.e. more than 136 mmol/l in men and 124 mmol/l in women) or abnormal creatinine clearance, congestive heart failure requiring pharmacologic treatment, and advanced age (more than 80 years of age).

Renal impairment represents a contraindication to metformin usage due to the increased risk of lactic acidosis, which is a form of metabolic acidosis due to the inadequate clearance of lactic acid from the blood. Although lactic acidosis linked to metformin is a rare condition, with an estimated prevalence of one to five cases per 100,000 population, it has a reported mortality of 30-50%.

However, recent studies have suggested that metformin can be used safely, unless the estimated glomerular filtration rate, which is the volume of fluid that is filtered from the capillaries of the glomeruli into the kidney tubules per unit time, falls below 30 ml/min. Moreover, a dose reduction is advised at 45 ml/min.

Congestive heart failure is typically considered to be a contraindication for metformin treatment, thus the drug is withheld from large numbers of patients with type 2 diabetes and coincident cardiac failure. More recent studies suggest that metformin may not be absolutely contraindicated and could be beneficial in such patients.

The drug label states that metformin treatment should not be initiated in patients older than 80 years of age unless their creatinine clearance is normal. Still, several studies of patients with type 2 diabetes, including those over 70 years of age, have shown that metformin treatment is not associated with significantly increased plasma lactate levels.

Therefore, a reasonable approach is to start with a low dose of about 250 mg twice a day and increase the dose weekly, based on tolerance and effect of the drug on the surrogate endpoint of blood glucose level, to a maximum dose of 2,000-2,500 mg per day. Metformin therapy should be interrupted if acute changes in renal function arise.

Guidelines for the clinical use

The consensus statement of the European Association for the Study of Diabetes and the American Dental Association recommends that metformin be initiated together with diet and exercise when patients have been diagnosed with type 2 diabetes. Additional antihyperglycemic agents are selected on the basis of clinically relevant issues, such as glucose-lowering effectiveness, risk of hypoglycemia, and effect on body weight.

Metformin remains the drug of choice for pharmacological treatment in insulin-resistant and obese diabetic individuals. Still, as the antihyperglycemic effects of metformin are similar in lean and obese subjects, it can also be recommended as a first-line treatment even without obesity.

The addition of metformin to insulin is advantageous compared to insulin alone. Furthermore, the addition of metformin to sulfonylureas in patients with secondary sulfonylurea failure is reasonable in view of their synergistic mechanisms of action. All these favorable effects have led to the widespread recommendation in evidence-based guidelines of many countries to use metformin as a first-line agent.

References

Further Reading

Last Updated: May 17, 2023

Dr. Tomislav Meštrović

Written by

Dr. Tomislav Meštrović

Dr. Tomislav Meštrović is a medical doctor (MD) with a Ph.D. in biomedical and health sciences, specialist in the field of clinical microbiology, and an Assistant Professor at Croatia's youngest university - University North. In addition to his interest in clinical, research and lecturing activities, his immense passion for medical writing and scientific communication goes back to his student days. He enjoys contributing back to the community. In his spare time, Tomislav is a movie buff and an avid traveler.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Meštrović, Tomislav. (2023, May 17). Metformin Contraindications. News-Medical. Retrieved on May 19, 2024 from https://www.news-medical.net/health/Metformin-Contraindications.aspx.

  • MLA

    Meštrović, Tomislav. "Metformin Contraindications". News-Medical. 19 May 2024. <https://www.news-medical.net/health/Metformin-Contraindications.aspx>.

  • Chicago

    Meštrović, Tomislav. "Metformin Contraindications". News-Medical. https://www.news-medical.net/health/Metformin-Contraindications.aspx. (accessed May 19, 2024).

  • Harvard

    Meštrović, Tomislav. 2023. Metformin Contraindications. News-Medical, viewed 19 May 2024, https://www.news-medical.net/health/Metformin-Contraindications.aspx.

Comments

  1. Mario Gabriel Mario Gabriel Macao S.A.R. says:

    Metformin can cause pheriferal Neuralgia ?

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Simple bean diet intervention demonstrates significant prebiotic effects