Dapagliflozin Versus Metformin for the Management of Antipsychotic-Induced Weight Gain: A Pragmatic Pilot Randomized Controlled Trial

June 6, 2026 updated by: Mohammed Al Alawi MD PhD MRCPsych ARABpsych OMSBpsych, Sultan Qaboos University

The goal of this clinical trial is to learn whether dapagliflozin can help manage weight gain caused by antipsychotic medications in people aged 16 years or older who are receiving antipsychotic treatment and have developed antipsychotic-induced weight gain.

The main questions it aims to answer are:

Can dapagliflozin reduce body weight as effectively and safely as metformin over the study period?

How do dapagliflozin and metformin compare in their effects on body weight, body mass index, waist circumference, blood sugar, HbA1c, lipid profile, psychiatric symptoms, quality of life, medication adherence, and side effects?

Researchers will compare dapagliflozin plus a common lifestyle program with metformin plus a common lifestyle program to see which treatment is more effective, better tolerated, and more acceptable for managing antipsychotic-induced weight gain.

Participants will:

Be randomly assigned to receive either dapagliflozin or metformin. Receive lifestyle advice, including dietary counselling, physical activity counselling, and behavioural support.

Attend clinic visits at baseline, Week 12, and Week 26 for weight, waist circumference, blood tests, medication review, and other assessments.

Receive telephone follow-up at Week 2, Week 6, and Week 18 to check medication adherence, side effects, tolerability, and lifestyle progress.

Complete questionnaires and clinical assessments related to physical activity, quality of life, psychiatric symptoms, and treatment tolerability.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

This is an open-label, pragmatic, parallel-group pilot randomized controlled trial comparing dapagliflozin with metformin for the management of antipsychotic-induced weight gain. The study will be conducted at the Department of Behavioral Medicine, Sultan Qaboos University Hospital, University Medical City, Muscat, Oman.

Antipsychotic-induced weight gain is a common and clinically important adverse effect of antipsychotic treatment. It may contribute to reduced treatment adherence, poorer quality of life, and increased cardiometabolic risk. Metformin is commonly used to manage antipsychotic-associated weight gain, but its use may be limited by gastrointestinal adverse effects, dose titration, and pill burden. Dapagliflozin, a sodium-glucose cotransporter 2 inhibitor, has demonstrated weight-reducing and metabolic benefits in other clinical populations, but its role in antipsychotic-induced weight gain remains insufficiently studied.

Participants will be randomized in a 1:1 ratio to receive either dapagliflozin plus a common lifestyle program or metformin plus a common lifestyle program. The trial will use a pragmatic PROBE-style design, with open-label treatment allocation and blinded outcome assessment and statistical analysis where feasible. Randomization will use a computer-generated sequence with allocation concealment.

The study is designed as a pilot trial to assess feasibility, tolerability, adherence, safety, and preliminary estimates of treatment effect to inform a future definitive trial. Standardized procedures will be used for participant follow-up, medication review, safety monitoring, and data collection. Adverse events and treatment tolerability will be monitored throughout the study, and serious adverse events will be reported according to institutional and ethics committee procedures.

Data will be collected by trained study personnel and entered into an electronic database with procedures to support completeness and accuracy. Analyses will be primarily descriptive and exploratory, consistent with the pilot nature of the trial, and will be used to refine assumptions for a future larger randomized controlled trial.

Study Type

Interventional

Enrollment (Estimated)

110

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Oman
      • Muscat, Oman
        • SQU
        • Contact:
        • Principal Investigator:
          • Mohammed Al Alawi, MD, PhD
        • Sub-Investigator:
          • Said Al Farsi, MD
        • Sub-Investigator:
          • Ghadeer Al Nuaimi, MD
        • Sub-Investigator:
          • Merah Al Busaidi, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • Patients aged ≥16 years
  • Diagnosis according to DSM-5 criteria, including:

Schizophrenia spectrum and other psychotic disorders, as summarized in the DSM-5 chapter Schizophrenia Spectrum and Other Psychotic Disorders, excluding:

Substance/medication-induced psychotic disorder Psychotic disorder due to another medical condition Catatonia associated with another mental disorder Catatonic disorder due to another medical condition Unspecified catatonia Bipolar and related disorders, as summarized in the DSM-5 chapter Bipolar and Related Disorders Depressive disorders, as summarized in the DSM-5 chapter Depressive Disorders Obsessive-compulsive and related disorders, as summarized in the DSM-5 chapter Obsessive-Compulsive and Related Disorders Other psychiatric conditions for which antipsychotic treatment is clinically indicated, as judged by the investigator Other conditions where antipsychotics are indicated

  • Receiving stable antipsychotic treatment for ≥3 months prior to enrollment

  • Evidence of antipsychotic-induced weight gain (AiWG), defined as:

    1. ≥7% increase in body weight from baseline following initiation of antipsychotic treatment, or
    2. BMI >25 kg/m² with clinically established antipsychotic-associated weight gain
  • Able to understand and comply with study procedures, as judged by the investigator
  • Able to provide written informed consent. For participants aged 16-17 years, assent and/or guardian consent will be obtained according to local ethics committee requirements.

Exclusion criteria:

  • Diabetes mellitus
  • Diagnosed patients of polycystic ovarian syndrome (PCOS)
  • Renal impairment defined as estimated glomerular filtration rate (eGFR <45 mL/min/1.73 m²)
  • Significant hepatic disease or other serious or unstable medical conditions that, in the opinion of the investigator, would make participation unsafe
  • Pregnant or breastfeeding females
  • Current use of metformin, dapagliflozin, or another sodium-glucose cotransporter 2 inhibitor.
  • Use of weight-loss medications or participation in structured weight-loss programs within the past 3 months
  • Recurrent genitourinary infections (if dapagliflozin is used)
  • Use of non-antipsychotic medications known to cause clinically significant weight gain, including but not limited to selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), mirtazapine, tricyclic antidepressants, valproate, lithium, corticosteroids, sedating antihistamines, or other medications as judged by the investigator
  • Unstable psychiatric condition or active substance use disorder that may impair the ability to adhere to study procedures, as judged by the investigator

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dapagliflozin
Other: Common Lifestyle Program
All participants will receive a standardized common lifestyle program. This will include dietary counselling, physical activity counselling, and behavioural support delivered at baseline and reinforced during scheduled in-person visits and telephone follow-up. Physical activity will be assessed using the International Physical Activity Questionnaire.
Drug: Dapagliflozin
Dapagliflozin will be administered orally at a dose of 10 mg once daily. Treatment will continue for 26 weeks. Participants will be monitored for adherence, tolerability, and adverse events, including genitourinary symptoms, dehydration, sick-day events, and symptoms suggestive of ketoacidosis.
Active Comparator: Metformin
Drug: Metformin
Metformin will be administered orally. Participants will start with 500 mg twice daily, taken with meals, and will be titrated to 1000 mg twice daily by the second week as tolerated. Slower titration may be used if gastrointestinal side effects occur. Treatment will continue for the study period, with the primary endpoint assessed after 26 weeks at the maximum tolerated dose.
Other: Common Lifestyle Program
All participants will receive a standardized common lifestyle program. This will include dietary counselling, physical activity counselling, and behavioural support delivered at baseline and reinforced during scheduled in-person visits and telephone follow-up. Physical activity will be assessed using the International Physical Activity Questionnaire.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Body Weight
Time Frame: Baseline, Week 12, and Week 26 at the maximum tolerated dose
Change in body weight from baseline to the primary endpoint. Body weight will be measured using standardized procedures and compared between the dapagliflozin plus common lifestyle program arm and the metformin plus common lifestyle program arm.
Baseline, Week 12, and Week 26 at the maximum tolerated dose

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Body Mass Index (BMI)
Time Frame: Baseline, Week 12, and Week 26
Change in BMI (kg/m²) from baseline to week 26 to evaluate overall body composition changes associated with each intervention.
Baseline, Week 12, and Week 26
Change in Waist Circumference
Time Frame: Baseline, Week 12, and Week 26
Change in waist circumference (measured at the midpoint between the lowest rib and iliac crest) from baseline to week 26, assessing central fat distribution.
Baseline, Week 12, and Week 26
Change in Fasting Plasma Glucose
Time Frame: Baseline, Week 12, and Week 26
Difference in fasting plasma glucose levels from baseline to week 26, reflecting glucose metabolism and glycemic control.
Baseline, Week 12, and Week 26
Change in Glycated Hemoglobin (HbA1c)
Time Frame: Baseline, Week 12, and Week 26
Change in HbA1c (%) from baseline to week 26, assessing long-term glucose regulation.
Baseline, Week 12, and Week 26
Change in Lipid Profile
Time Frame: Baseline, Week 12, and Week 26
Change in total cholesterol, LDL, HDL, and triglycerides from baseline to week 26, evaluating metabolic health and cardiovascular risk.
Baseline, Week 12, and Week 26
Change in psychiatric symptom severity
Time Frame: Baseline, Week 12, and Week 26
  • Psychotic symptom severity will be assessed using the Brief Psychiatric Rating Scale, an 18-item clinician-rated scale. Total scores range from 18 to 126, with higher scores indicating greater psychotic symptom severity.
  • Depressive symptom severity will be assessed using the 17-item Hamilton Depression Rating Scale. Total scores range from 0 to 52, with higher scores indicating greater depressive symptom severity.
  • Manic symptom severity will be assessed using the Young Mania Rating Scale, an 11-item clinician-rated scale. Total scores range from 0 to 60, with higher scores indicating greater manic symptom severity.
  • Obsessive-compulsive symptom severity will be assessed using the Yale-Brown Obsessive Compulsive Scale. Total scores range from 0 to 40, with higher scores indicating greater obsessive-compulsive symptom severity.
Baseline, Week 12, and Week 26
Change in quality of life
Time Frame: Baseline, Week 12, and Week 26
Change in health-related quality of life assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L).
Baseline, Week 12, and Week 26
Medication adherence
Time Frame: Week 2, Week 6, Week 12, Week 18, and Week 26
Assessment of participant adherence to the assigned intervention during scheduled visits and telephone follow-up.
Week 2, Week 6, Week 12, Week 18, and Week 26
Adverse events and tolerability
Time Frame: Week 2, Week 6, Week 12, Week 18, and Week 26
Frequency, severity, duration, action taken, and outcome of adverse events and tolerability issues reported during the study period.
Week 2, Week 6, Week 12, Week 18, and Week 26

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Physical activity assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF)
Time Frame: Baseline, Week 12, and Week 26
Self-reported physical activity will be assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Physical activity will be measured to describe participant activity levels and to support adjustment for physical activity as a potential confounding variable in analyses of body weight and metabolic outcomes.
Baseline, Week 12, and Week 26

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sultan Qaboos University

Investigators

  • Study Chair: Mohammed Al Alawi, MD, PhD, Sultan Qaboos University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

November 1, 2028

Study Completion (Estimated)

December 1, 2028

Study Registration Dates

First Submitted

January 6, 2026

First Submitted That Met QC Criteria

January 6, 2026

First Posted (Actual)

January 15, 2026

Study Record Updates

Last Update Posted (Actual)

June 10, 2026

Last Update Submitted That Met QC Criteria

June 6, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AIWG2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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