Medication Adjustment After Bariatric and Metabolic Surgery: A Review of Current Evidence and Clinical Practice...

Bariatric and metabolic surgery (BMS) is the most effective treatment for severe obesity and its related comorbidities. Rapid metabolic improvement following surgery frequently leads to the reduction or discontinuation of medications for obesity-related comorbidities. However, there are no established guidelines regarding timing or criteria for dose adjustment. A narrative review examined major clinical trials, meta-analyses, and society guidelines relevant to BMS. Evidence from previous and recent studies was synthesized to summarize pharmacokinetic alterations, disease-specific medication adjustments, and long-term deprescription patterns following BMS. Postoperative anatomical changes-including reduced gastric surface area, intestinal bypass, and altered acidity-affect the absorption of many oral drugs, requiring early dose adjustment. For type 2 diabetes mellitus, patients using <30 units/day of basal insulin can discontinue insulin after surgery, whereas those using ≥30 units/day typically require a 50-80% dose reduction. Most patients taking a single oral hypoglycemic agent may stop medication, while metformin monotherapy is recommended when glycated hemoglobin (HbA1c) <9% and dual therapy when HbA1c ≥9%. In hypertension, discontinuation of one antihypertensive drug usually results in approximate 10 mmHg reduction in systolic blood pressure. Diuretics should be withheld for the first 2 weeks postoperatively to prevent dehydration and excessive volume loss. For dyslipidemia, lipid-lowering agents are adjusted according to postoperative lipid profile changes and restarted if necessary. In psychiatric disorders, early resumption of preoperative medications is recommended to prevent withdrawal symptoms or relapse. BMS enables early medication reduction across comorbidities, yet individualized pharmacologic management remains essential to sustain metabolic improvement and long-term disease control.