Medication and supplement pharmacokinetic changes following bariatric surgery: A systematic review and meta‐analysis

Summary Objectives To evaluate the impact of bariatric surgery on the pharmacokinetic (PK) parameters of orally administered medications and supplements. Methods Systematic searches of bibliographic databases were conducted to identify studies. Pooled effect estimates from different surgical procedures were calculated using a random‐effects model. Results Quantitative data were synthesized from 58 studies including a total of 1985 participants. Whilst 40 medications and 6 supplements were evaluated across these studies, heterogeneity and missing information reduced the scope of the meta‐analysis to the following medications and supplements: atorvastatin, paracetamol, omeprazole, midazolam, vitamin D, calcium, zinc, and iron supplements. There were no significant differences in PK parameters post‐surgery for the drugs atorvastatin and omeprazole, and supplements calcium, ferritin, and zinc supplements. Paracetamol showed reduced clearance (mean difference [MD] = −15.56 L/hr, p = 0.0002, I 2 = 67%), increased maximal concentration (MD = 6.90 μg/ml, p = 0.006, I 2 = 92%) and increased terminal elimination half‐life (MD = 0.49 hr, p < 0.0001, I 2 = 3%) post‐surgery. The remaining 36 medications and 2 supplements were included in a systematic review. Overall, 18 of the 53 drugs and supplements showed post‐operative changes in PK parameters. Conclusion This study demonstrates heterogeneity in practice and could not reach conclusive findings for most PK parameters. Prospective studies are needed to inform best practice and enhance patient healthcare and safety following bariatric surgery.