Schizophr Bull

Antipsychotic-induced weight gain: New guideline recommends metformin

January 2, 2025

An algorithm developed by an international group specifies metformin use based on an antipsychotic’s weight-gain risk.

• high-risk antipsychotic (olanzapine, clozapine): Co-commencement of metformin is recommended.
• medium-risk antipsychotic (quetiapine, paliperidone, risperidone): Co-commencement of metformin is recommended if any of the following are present: hypertension, dyslipidemia, diabetes/pre-diabetes, BMI >25, or age 10-25 years. Otherwise, metformin would be prescribed after meeting observed weight gain thresholds.
• low-risk antipsychotics (all others): Metformin would be prescribed after meeting observed weight gain thresholds.

For patients with preexisting obesity (BMI 30+)—or those with BMI 27-30 who also have hypertension, dyslipidemia, diabetes/prediabetes, or obstructive sleep apnea—a GLP-1 agonist is appropriate instead. For all patients, diet and lifestyle changes are recommended concomitantly.

Background: Metformin is the only drug with demonstrated efficacy for antipsychotic-induced weight gain prevention. It has been shown to reduce weight gain by over 4 kg compared with controls.

Guideline development: Members of the international PROGRESS project steering group used a consensus process for the algorithm and evidence grading, followed by independent external review by experts and patients.

Source:

Carolan A, et al. (2024, December 9). Schizophr Bull. Metformin for the Prevention of Antipsychotic-Induced Weight Gain: Guideline Development and Consensus Validation. https://pubmed.ncbi.nlm.nih.gov/39657713/