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The effect of gastric bypass on the pharmacokinetics of serotonin reuptake inhibitors

Hamad GG, Helsel JC, Perel JM, Kozak GM, McShea MC, Hughes C, Confer AL, Sit DK et al.

The American journal of psychiatry, 2012

12 participants · 72 citations

Abstract

Objective: Morbidly obese patients frequently present with mood and anxiety disorders, which are often treated with serotonin reuptake inhibitors (SRIs). Having observed that patients treated with SRIs frequently relapse after Roux-en-Y gastric bypass surgery, the authors sought to assess whether SRI bioavailability is reduced postoperatively.

Method: Twelve gastric bypass candidates treated with an SRI for primary mood or anxiety disorders were studied prospectively. Timed blood samples for SRI plasma levels were drawn for pharmacokinetic studies before surgery and 1, 6, and 12 months afterward. Maximum concentration, time to maximum concentration, and area under the concentration/time curve (AUC) were determined.

Results: In eight of the 12 patients, AUC values 1 month after surgery dropped to an average of 54% (SD=18) of preoperative levels (range=36%-80%); in six of these patients, AUC values returned to baseline levels (or greater) by 6 months. Four patients had an exacerbation of depressive symptoms, which resolved by 12 months in three of them. Three of the four patients had a reduced AUC level at 1 month and either gained weight or failed to lose weight between 6 and 12 months. Normalization of the AUC was associated with improvement in symptom scores.

Conclusions: Patients taking SRIs in this study were at risk for reduced drug bioavailability 1 month after Roux-en-Y gastric bypass. The authors recommend close psychiatric monitoring after surgery.

How strong is the evidence?

Evidence Hub reads this as a clinical trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 12 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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