Effect of Roux‐En‐Y Gastric Bypass in the Pharmacokinetics of (R)‐Carvedilol and (S)‐Carvedilol

Abstract

Roux‐en‐Y gastric bypass is one of the most common surgical treatments for obesity due to the effective long‐term weight loss and remission of associated comorbidities. Carvedilol, a third‐generation β‐blocker, is prescribed to treat cardiovascular diseases. This drug is a weak base with low and pH‐dependent solubility and dissolution and high permeability. As the changes in the gastrointestinal tract anatomy and physiology after roux‐en‐Y gastric bypass can potentially affect drug pharmacokinetics, this study aimed to assess the effect of roux‐en‐Y gastric bypass on the pharmacokinetics of carvedilol enantiomers. Nonobese (n = 15, body mass index < 25 kg/m2), obese (n = 19, body mass index ≥ 30), and post‐roux‐en‐Y gastric bypass subjects submitted to surgery for at least 6 months (n = 19) were investigated. All subjects were administered a single oral dose of 25‐mg racemic carvedilol, and blood was sampled for up to 24 hours. Plasma concentrations of (R)‐ and (S)‐carvedilol were determined by liquid chromatography–tandem mass spectrometry. The maximum plasma concentration (Cmax) and the area under the plasma concentration‐time curve (AUC) of (R)‐carvedilol were 2‐ to 3‐fold higher than (S)‐carvedilol in all groups. Obese subjects have shown reduced Cmax of (R)‐ and (S)‐carvedilol without changing the AUC. Post‐roux‐en‐Y gastric bypass subjects presented a 3.5‐fold reduction in the Cmax of the active (S)‐carvedilol and a 1.9 reduction in the AUC from time 0 to infinity compared to nonobese subjects. The time to reach Cmax of (S)‐carvedilol increased 2.5‐fold in post‐roux‐en‐Y gastric bypass subjects compared to obese or nonobese. Although the β‐blockade response was not assessed, the reduced exposure to carvedilol in subjects post‐roux‐en‐Y gastric bypass may be clinically relevant and require dose adjustment.