Prevalence of Psychotropic Drug Treatment Interventions in Patients Undergoing Metabolic and Bariatric Surgery: A...

The pharmacokinetics of oral psychotropic drugs can change after metabolic and bariatric surgery (MBS), affecting drug exposure. Given the risk of psychiatric decompensation, patients using psychotropic medications constitute a high-risk group requiring careful post-MBS monitoring. In particular, lithium, tricyclic antidepressants (TCAs), and clozapine are of concern because of their well-established dose-effect relationships, susceptibility to MBS-related exposure changes, and suitability for therapeutic drug monitoring (TDM). This study aimed to examine the prevalence of treatment interventions related to these medications in bariatric patients to prevent drug-related problems such as under- or overexposure requiring dosage adjustments or drug discontinuation.

In this retrospective study, patient records from January 2017 to December 2023 were reviewed. Patients who underwent MBS and were using lithium, TCAs (amitriptyline, clomipramine, dosulepin, doxepin, imipramine, maprotiline, nortriptyline), and/or clozapine were included. Baseline characteristics, treatment interventions, and available drug plasma concentrations were collected preoperatively and up to one year postoperatively.

A total of 163 patients were included. Psychotropic drug adjustments were observed in 27 patients (16.6%) within the first year following MBS. Both pre- and postoperative drug plasma concentrations were available for three patients (1.8%). Three patients experienced worsening of psychiatric symptoms that necessitated hospitalization or intensive monitoring. No statistically significant differences in intervention rates were observed among patients with psychiatric disorders or pain.

Although only a minority of patients required psychotropic drug treatment interventions, monitoring psychotropic drug treatment is essential for safe and effective treatment post-MBS. Greater attention is needed regarding altered drug exposure, and plasma concentration monitoring may help optimize psychotropic pharmacotherapy in these patients.