Bariatric surgery may alter the absorption, distribution, metabolism or elimination of orally administered medicines via changes to the gastrointestinal tract anatomy, body weight and adipose tissue composition. This could result in changes in efficacy or the development of adverse effects which may vary with the type of bariatric surgery. Despite the number of bariatric surgeries performed, these changes remain poorly documented and understood.
Patients undergoing bariatric surgery often have comorbidities requiring multiple medicines. Pharmacotherapy may be complicated not only by changes in absorption and metabolism following surgery, but also by improvement in condition, such as diabetes and hypertension, after surgery. Patients invariably require modifications to the doses of their medicines and often the dose formulation.
We will present a case and apply pharmacokinetic principles and the published evidence to date to highlight potential implications for some common medicines.
Optimisation of medicines needs to be individualised. Clinical pharmacists can assist in managing medicines selection and dose changes pre- and post- bariatric surgery. This example highlights improved patient care through multidisciplinary collaboration.1
References
1.Girolamo, T. and Allin, R. Aust Prescr 2022;45:162–6