55 - Antidepressants

Antidepressants

850 The Maudsley® Prescribing Guidelines in Psychiatry CHAPTER 10 Antidepressants Table 10.16 summarises the use of antidepressants in bariatric surgery. Table 10.16  Antidepressants in bariatric surgery. Medication Specific evidence and considerations SSRIs4,8,9 Evidence demonstrates that plasma levels may be significantly reduced following RYGB or sleeve gastrectomy. The concentration of SSRIs may drop initially and then rebound within a few months; dose adjustments occurring in the immediate postoperative period might be temporary. Malabsorption has been implicated in cases of discontinuation symptoms and loss of efficacy. Sertraline and vortioxetine absorption appear to be the most affected and fluoxetine the least. SNRIs9–11 Suggest avoid duloxetine owing to significant reduction in levels and risk of discontinuation syndrome. The absorption of venlafaxine MR capsules seems not to be altered by RYGB Mirtazapine9,12–14 Plasma levels may be significantly reduced following RYGB or sleeve gastrectomy. Dose increase is often needed. Increased appetite and weight gain are possible. TCAs15,16 Single case report suggests therapeutic plasma levels can be achieved within usual dose range after RYGB. Plasma levels may be increased after significant weight loss. Consider monitoring levels and reducing dose. Agomelatine No data available on absorption after bariatric surgery. Follow general recommendations. Dextromethorphan and bupropion There are no studies of the combined formulation after bariatric surgery No pharmacokinetic changes after bariatric surgery were reported for dextromethorphan liquid in the short or long term.5,17 In an in vitro model bupropion was found to have a significantly higher dissolution after RYGB which may lead to increased bioavailability.18 Esketamine nasal spray19 Primarily absorbed via nasal mucosa. Problems after bariatric surgery are not expected. General summary ■ ■Antidepressants are the best-studied psychotropics in the bariatric population. Current evidence suggests that antidepressant absorption is reduced after surgery (though studies are mostly limited to SSRIs after RYGB). ■ ■Signs of reduced absorption may include the rapid development of discontinuation symptoms and later loss of efficacy. Patients should be made aware of discontinuation symptoms and signs of relapse and seek medical advice if they occur. ■ ■Patients require close monitoring as those at risk of reduced absorption cannot be reliably predicted. ■ ■The risk of gastric bleeds with bariatric surgery will probably be increased by serotonergic antidepressants. MR, modified release; RYGB, Roux-­en-­Y gastric bypass; TCAs, tricyclic antidepressants.