Case of Medication-Induced Weight Gain and Diabetes

Ginna S. Eynon, PharmD Candidate 2026
Joshua J. Neumiller, PharmD, CDCES, FADCES, FASCP

Department of Pharmacotherapy
College of Pharmacy and Pharmaceutical Sciences
Washington State University

A 29-year-old female with a history of schizophrenia and depression was referred for a pharmacotherapy evaluation by her social work case manager. During a recent visit by the social worker, the patient and her mother (who serves as her caregiver) described a weight gain of more than 15 pounds over the last 3 months. The patient’s mother, who has type 2 diabetes, expressed concern about her daughter developing diabetes secondary to her recent weight gain.

Medications at time of encounter:

• Sertraline (Zoloft) 100 mg once daily
• Olanzapine (Zyprexa) 20 mg once daily

Upon further discussion with the patient’s mother, the patient was diagnosed with schizophrenia approximately 10 months prior and her olanzapine dose was increased to 20 mg once daily about 4 months ago. Her mother reported that her schizophrenia symptoms were improved at the 20 mg olanzapine dose. During the visit, a random fingerstick glucose measurement was performed, showing a blood glucose of 185 mg/dL.

A notable number of medications and medication classes are associated with drug-induced weight gain and hyperglycemia.¹ One such class are the second generation (atypical) antipsychotics, with one systematic review and meta-analysis reporting olanzapine as the agent associated with the largest degree of weight gain.² While the American Diabetes Association (ADA) recommends minimizing use of medications for comorbid conditions that are associated with weight gain,¹ it not always possible to do so given the comorbid medical condition(s) and/or individualized management needs. The ADA previously published a position statement in collaboration with the American Psychiatric Association (APA), the American Association of Clinical Endocrinologists (AACE), and the North American Association for the Study of Obesity.³ While the publication was published in 2004 and is now dated, it provides some practical recommendations for screening and monitoring in people taking second generation antipsychotics. Recommended baseline screening includes assessment of family history of obesity, diabetes, dyslipidemia, hypertension and/or cardiovascular disease; weight and height; waist circumference; blood pressure; and fasting glucose and lipid values. For follow-up, it is recommended that weight and body mass index (BMI) be assessed at 4, 8, and 12 weeks and every 3 months thereafter. Follow-up blood pressure and fasting glucose screening is additionally recommended at 12-weeks and annually after initiation of the antipsychotic.

In addition to lifestyle interventions to promote a healthy diet and physical activity, multiple medications have demonstrated effectiveness in treating antipsychotic-induced weight gain, including metformin, topiramate (Topamax), and liraglutide (Victoza).⁴

Recommendations made:

1. The patient was referred to her primary care provider for a metabolic workup (e.g., blood glucose, blood pressure, lipids).
2. The patient was referred for lifestyle education (diet and physical activity) to promote weight loss.
3. Depending on the results of her metabolic workup (including kidney function and B12 levels), a recommendation was made to consider initiation of metformin (target dose after up-titration of 2,000 mg daily) to promote weight loss and improve glycemia.

Lessons learned:

• A variety of medications are associated with treatment-emergent weight gain and hyperglycemia.
• Second-generation antipsychotics, such as olanzapine, are associated with weight gain and risk for development type 2 diabetes, yet are often clinically necessary.
• Baseline and follow-up metabolic screening is recommended for people initiating therapy with a second generation antipsychotic.
• Agents such as metformin, topiramate, and liraglutide have demonstrated effectiveness in treating antipsychotic-induced weight gain.

References:

1. American Diabetes Association Professional Practice Committee. 8. Obesity and weight management for the prevention and treatment of type 2 diabetes: Standards of Care in Diabetes – 2024. Diabetes Care 2024;47(Suppl. 1):S145-S157
2. Deomecq JP, Prutsky G, Leppin A, et al. Drugs commonly associated with weight change: a systematic review and meta-analysis. J Clin Endocrinol Metab 2015;100(2):363-370
3. American Diabetes Association, et al. Consensus development conference on antipsychotic drugs and obesity and diabetes. Diabetes Care 2024;27(2):596-601
4. Stogios N, Hahn MK, Lunsky Y, et al. Metformin for the treatment of antipsychotic-induced metabolic disturbances in people with intellectual and developmental disabilities. J Psychiatry Neurosci 2023;48(2):E99-E101