Bariatric surgery and medicines: from first principles to practice.

Obesity is a major public health issue with significant health and financial costs. Almost one in three Australian adults are living with obesity Bariatric surgery can have a role in the management of obesity. There is evidence for its effectiveness in preventing or reversing chronic health conditions The type of bariatric surgery can significantly impact the absorption, distribution, metabolism or elimination of orally administered drugs. Some changes can be predicted from pharmacokinetic and physiological effects, but management should be individualised The effect of weight loss itself after bariatric surgery may require drug doses to be altered A review of the patient's medicines and ongoing follow-up are important before and after surgery to ensure optimal outcomes.