Sola, Christopher L.

Background: Lithium is a mainstay treatment for bipolar disorder, but its narrow therapeutic index and susceptibility to pharmacokinetic interactions make appropriate monitoring crucial. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), such as semaglutide, are increasingly prescribed for type 2 diabetes and weight management. Scarce evidence exists on the potential interaction between semaglutide and lithium. Methods: We present 3 cases involving patients on stable lithium regimens who were initiated on semaglutide, reviewing potential mechanisms underlying the interaction between them. Findings: In 2 cases, lithium levels increased significantly, leading to toxicity despite stable renal function and no changes in concurrent medications. In the third case, preemptive reductions in lithium dosage mitigated toxicity, although lithium levels remained higher than anticipated. Mechanistic hypotheses that might contribute to semaglutide-associated elevated lithium levels include altered kidney function, dehydration from reduced oral intake, vomiting, or diarrhea, and delayed gastric emptying. Conclusions: To our knowledge, this is one of the first documented case series describing a potential interaction between semaglutide and lithium in the medical literature. These cases underscore the importance of vigilant monitoring when combining lithium with semaglutide, and potentially other GLP-1 RAs. Baseline renal function, hydration status, and lithium levels should be assessed before initiating semaglutide, and lithium levels should be monitored more frequently during therapy. Clinicians prescribing semaglutide to patients on lithium should exercise caution, monitor for signs of toxicity, and provide appropriate patient education. Further research is needed to elucidate the mechanisms of this potential interaction and its clinical significance.

Background: Single infusions of ketamine have been used successfully to achieve improvement in depressed patients. Side effects during the infusions have been common. It is not known whether serial infusions or lower infusion rates result in greater efficacy. Methods: Ten depressed patients were treated with twice weekly ketamine infusions of ketamine 0.5 mg/kg administered over 100 min until either remission was achieved or four infusions were given. Side effects were assessed with the Young Mania Rating Scale (YMRS) and the Brief Psychiatric Rating Scale (BPRS). Patients were followed naturalistically at weekly intervals for four weeks after completion of the infusions. Results: Five of 10 patients achieved remission status. There were no significant increases on the BPRS or YMRS. Two of the remitting patients sustained their improvement throughout the four week follow-up period. Conclusions: Ketamine infusions at a lower rate than previously reported have demonstrated similar efficacy and excellent tolerability and may be more practically available for routine clinical care. Serial ketamine infusions appear to be more effective than a single infusion. Further research to test relapse prevention strategies with continuation ketamine infusions is indicated.