Effect of Obesity on the Use of Antiarrhythmics in Adults With Atrial Fibrillation: A Narrative Review

Background Atrial fibrillation (AF) and obesity coexist in approximately 37.6 million and 650 million people globally, respectively. The anatomical and physiological changes in individuals with obesity may influence the pharmacokinetic properties of drugs. Aim This review aimed to describe the evidence of the effect of obesity on the pharmacokinetics of antiarrhythmics in people with AF. Methods Three databases were searched from inception to June 2023. Original studies that addressed the use of antiarrhythmics in adults with AF and concomitant obesity were included. Results A total of 4549 de‐duplicated articles were screened, and 114 articles underwent full‐text review. Ten studies were included in this narrative synthesis: seven cohort studies, two pharmacokinetic studies, and a single case report. Samples ranged from 1 to 371 participants, predominately males (41%–85%), aged 59–75 years, with a body mass index (BMI) of 23–66 kg/m 2 . The two most frequently investigated antiarrhythmics were amiodarone and dofetilide. Other drugs investigated included diltiazem, flecainide, disopyramide, propafenone, dronedarone, sotalol, vernakalant, and ibutilide. Findings indicate that obesity may affect the pharmacokinetics of amiodarone and sodium channel blockers (e.g., flecainide, disopyramide, and propafenone). Factors such as drug lipophilicity may also influence the pharmacokinetics of the drug and the need for dose modification. Discussion Antiarrhythmics are not uniformly affected by obesity. This observation is based on heterogeneous studies of participants with an average BMI and poorly controlled confounding factors such as multimorbidity, concomitant medications, varying routes of administration, and assessment of obesity. Controlled trials with stratification at the time of recruitment for obesity are necessary to determine the significance of these findings.