Changes in utilization of immediate-release, extended-release, and liquid formulation medications relative to...

Changes in gut anatomy following bariatric surgery impacts medication absorption, often requiring changes in medication formulations.

To assess changes in utilization of extended-release (ER), immediate-release (IR), and liquid formulations 360 days before and after bariatric surgery.

Large U.S. administrative claims database of privately insured beneficiaries, January 2005 through December 2018.

We included patients aged ≥18 years with 360 days of continuous enrollment before and after date of bariatric surgery (Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG]). The proportion of each formulation (ER, IR, or liquid) of oral prescription medications filled during the study period were assessed in twelve 30-day windows before and after bariatric surgery and stratified by bariatric surgery type. Segmented regression analysis was used to assess filled medication categorized by formulation before and after bariatric surgery overall and RYGB relative to SG.

Among 122,866 included patients, there were increases in the proportion of patients on each formulation before and after surgery attributed to proton pump inhibitors, opioids, antiemetics, and ursodiol. After removing these acutely used medications, we found a 40% immediate reduction in patients on ER medications (P < .0001), 15% immediate reduction in patients on IR medications (P < .0001), and a nonsignificant increase in patients on liquid formulations (P = .1340).

Despite reductions in ER formulations, many patients continued on this formulation which may potentially contribute to poor outcomes.