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Metformin Should be ‘Protocolized’ for Anti-Psychotic Weight Gain

— June 14, 2022

Psychiatrist says Metformin should be given upfront to patients on anti-psychotic medications to manage weight.

A new evidence-based Irish guideline for the management of weight gain associated with the use of anti-psychotic medications recommends physicians simultaneously prescribe metformin.  The guideline suggests that this should be protocol for any patients who experience at least 7% weight gain within their first month of treatment.  The new study was the topic of discussion during one of the sessions of the XXXV Argentine Congress of Psychiatry of the Association of Argentine Psychiatrists (APSA 2022), held from April 27 to 30, as well as presented at the European Congress on Obesity (ECO) 2022 in the Netherlands, May 4 to 7.

Metformin is used to treat type 2 diabetes.  It helps to control the amount of glucose in the bloodstream and also decreases the amount of glucose absorbed from food and the amount made by the liver.

“The guideline encourages psychiatrists not to underestimate the adverse metabolic effects of their treatments and encourages them to contemplate and carry out this prevention and management strategy,” said María Delia Michat, PhD, professor of clinical psychiatry and psychopharmacology at the APSA Postgraduate Training Institute, Buenos Aires, Argentina.  “Although it is always good to work as a team, it is usually we psychiatrists who coordinate the pharmacological treatment of our patients, and we have to know how to manage drugs that can prevent cardiovascular disease.  The new guideline is helpful because it protocolizes the use of metformin, which is the cheapest drug and has the most evidence for anti-psychotic-induced weight gain.”

Metformin Should be 'Protocolized' for Anti-Psychotic Weight Gain
Photo by Pavel Danilyuk from Pexels

Michat noted further, patients with schizophrenia have obesity rates that are “40% higher than in the general population, and 80% of patients develop weight gain after their first treatment.  Right away, weight gain is seen in the first month.  And it is a serious problem, because patients with schizophrenia, major depression, or bipolar disorder already have an increased risk of premature mortality, especially from cardiovascular diseases, and they have an increased risk of metabolic syndrome.  And we sometimes give drugs that further increase that risk.”

Most doctors still suggest lifestyle changes rather than drug treatment to mitigate medication weight gain.  However, it is often difficult to counteract the effects of anti-psychotics even with dietary changes and regular exercise.  The blood will still metabolize glucose insufficiently so taking this route is likely to lead to a lot of extra work for no reason.

Michat noted that so far, major guidelines, including the Canadian Network for Mood and Anxiety Treatments [CANMAT]/International Society for Bipolar Disorders [ISBD] for bipolar disorder and the American Psychiatric Association [APA] for schizophrenia) “say very little on how to address this complication.”  When it is mentioned, the organizations propose counterbalancing weight gain solely with lifestyle changes.

The new clinical practice guideline, published in Evidence-Based Mental Health, analyzed 1270 scientific articles and 26 in depth, including seven randomized clinical trials and a 2016 systematic review and meta-analysis.  After thorough research, the team strongly recommended supplementing anti-psychotic drug treatment with metformin after patients have their kidney function evaluated.  The proposed starting dosage is 500 mg twice per day.


Early Metformin Minimizes Antipsychotic-Induced Weight Gain

Medline Plus: Metformin

Metformin in the management of antipsychotic-induced weight gain in adults with psychosis: development of the first evidence-based guideline using GRADE methodology

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