Changes in Antidepressant Absorption After Metabolic Bariatric Surgery

Area of Science:

• Pharmacology
• Gastroenterology
• Endocrinology

Background:

• Metabolic bariatric surgery (MBS), especially Roux-en-Y gastric bypass (RYGB), is effective for weight loss.
• The hypoabsorptive nature of RYGB may impact drug metabolism.
• Understanding these effects is crucial for patients on chronic medications.

Purpose of the Study:

• To evaluate the impact of RYGB on antidepressant pharmacokinetics.
• To assess if antidepressant management requires adjustments post-MBS.
• To identify potential drug absorption patterns after RYGB.

Main Methods:

• Retrospective longitudinal study with intra-individual comparisons.
• Analyzed patients on antidepressants before and after RYGB (2014-2019).
• Compared apparent oral clearance (CL/F) and concentration/dose ratio (CDR) pre- and post-surgery at multiple time points.

Main Results:

• Fourteen patients (mean age 48.92 years, BMI 37.32 kg/m²).
• Antidepressant levels remained within therapeutic ranges post-surgery.
• Significant variations in fluoxetine concentrations and CDR observed between 1 and 2 months post-surgery (p=0.022).
• An inverse association between BMI and D-fluoxetine CDR was noted (p=0.004).

Conclusions:

• Chronic antidepressant use generally does not require significant management changes post-MBS.
• Distinct absorption patterns for antidepressants were observed, suggesting metabolic pathway influence.
• The association between D-fluoxetine CDR and BMI may relate to altered CYP enzyme function after MBS.