Leung, Jonathan G.

Abstract Introduction Clozapine-induced constipation may occur in at least 60% of patients, with first-line options typically involving polyethylene glycol or sennosides. However, there may be adherence barriers to an over-the-counter bowel regimen due to the dosage form, lack of insurance coverage, or lack of benefit. One possible solution to address these adherence barriers may include prescribing a secretagogue laxative. However, there is limited literature supporting the use of secretagogue laxatives in clozapine-associated constipation. A case series is presented in which adherence barriers impeded the use of over-the-counter laxatives, and a secretagogue laxative was implemented to manage clozapine-induced constipation. Case Report In 4 cases, lubiprostone or linaclotide was initiated, either as monotherapy or in combination with over-the-counter laxatives. Reasons for secretagogue laxative initiation included: (1) reducing a complex over-the-counter laxative regimen, (2) a lack of insurance coverage of over-the-counter laxatives, (3) dissatisfaction with polyethylene glycol’s palatability, and (4) cognitive impairment leading to decreased adherence to polyethylene glycol. Discussion It is important that clozapine-induced constipation is managed adequately to prevent severe consequences of gastrointestinal hypomotility. In addition to timely initiation and titration of constipation pharmacotherapy, adherence should be assessed. When adherence barriers to the use of over-the-counter laxatives are present, the use of a secretagogue laxative may be an option, recognizing there is limited evidence to guide this decision. Conclusion In these cases, adherence barriers to over-the-counter laxatives were identified. A secretagogue laxative was implemented, well-tolerated, and able to be continued for the duration of follow-up.

Background: Ketamine and esketamine are increasingly used for treatment-resistant depression (TRD), yet their hepatic safety profile with repeated or long-term use remains poorly characterized. Chronic recreational ketamine abuse has been linked to cholestasis and cholangiopathy, raising concern that therapeutic use may carry similar risks. No systematic data exist on liver enzyme trajectories or biliary injury at subanesthetic doses used for depression. Methods: This historical cohort study included adults with TRD receiving IV ketamine or intranasal (IN) esketamine at the Mayo Clinic Ketamine Clinic (2017 to 2024). Patients were eligible if they had at least one liver enzyme value (AST, ALT, ALP, or bilirubin) within 12 months before through 3 months after treatment. Longitudinal enzyme trajectories were modeled using generalized linear-mixed models with a Gamma distribution. Clinically significant elevation was defined as ≥2× the upper limit of normal (ULN). Wilcoxon signed-rank tests compared pretreatment and post-treatment paired values. Results: Of 104 enrolled patients, 74 had liver enzyme data available; 51 had post-initiation data. Median age was 51.5 years; 72% were female. Most (78.4%) received IV ketamine. No clinically meaningful changes in enzyme trajectories were observed. Three patients (5.9%) had elevations ≥2× ULN, all attributable to alcohol use, myalgias, or pre-existing hepatic steatosis rather than (es)ketamine. Conclusions: Subanesthetic IV ketamine (0.5 mg/kg) and FDA-approved IN esketamine doses were not associated with clinically significant liver enzyme elevations in this real-world TRD cohort. Current evidence does not support routine hepatic monitoring for asymptomatic patients, although prospective, larger-scale studies are needed to confirm these findings.

Few pharmacologic options exist for patients with clozapine-resistant schizophrenia (CRS) or schizoaffective disorder. Xanomeline/trospium represents a new class of antipsychotic medication that has efficacy as monotherapy for schizophrenia. Despite distinct mechanistic differences from standard antipsychotics, phase III evidence suggest limited benefit of xanomeline/trospium in the augmentation of non-clozapine antipsychotics. Research on the use of xanomeline/trospium in patients with clozapine-resistant illness or with partial response to clozapine is even more limited. Two cases of this combination are described with a discussion on key considerations for the management of CRS. The first case is a 42-year-old patient whose clozapine dose was limited by supratherapeutic clozapine levels in response to minor infections. She was ultimately stabilized on a combination of clozapine and xanomeline/trospium, with yet further improvements from electroconvulsive therapy (ECT). The second case is a 31-year-old patient who elected to discontinue clozapine and ECT due to cognitive side effects, despite improvement in psychosis. The addition of xanomeline/trospium to clozapine caused sialorrhea and did not produce observable clinical benefits and was thus discontinued. These case reports describe clozapine-resistant patients who were trialed on xanomeline/trospium combined with clozapine and still required consideration of ECT for symptom control. Overall, future investigation into xanomeline/trospium effectiveness as an augmentation agent or as monotherapy for CRS is necessary to guide clinical decision-making.

ABSTRACT Introduction Sodium‐glucose cotransporter‐2 inhibitors (SGLT2i), initially developed for type 2 diabetes, have shown promise in improving renal outcomes in patients with and without diabetes. However, their effect on lithium‐associated kidney dysfunction remains unknown. Methods This historical cohort study included patients from Mayo Clinic (2001–2023) with mood disorders who received lithium for ≥ 6 months and later used SGLT2i for ≥ 1 month. Data on SGLT2i use and lithium treatment were extracted from electronic health records. Serum creatinine values were used to calculate estimated glomerular filtration rate (eGFR) trajectories. Linear mixed‐effects models with piecewise linear splines were used to estimate eGFR slopes before and after SGLT2i initiation, adjusted for age and sex. Results Fifty‐six patients (mean age 57.4 years, 46.4% female), predominantly with bipolar disorder (87.5%), were included. The mean eGFR, measured nearest to SGLT2i initiation, was 77.9 ± 26.0 mL/min/1.73 m 2 , and the mean duration of SGLT2i use was 19.5 ± 17.8 months. Before SGLT2i initiation, eGFR declined at a rate of −1.43 mL/min/1.73 m 2 per year ( p < 0.001). After initiation, eGFR increased by 0.69 mL/min/1.73 m 2 per year, reflecting a + 2.13 change ( p = 0.025). Sensitivity analyses, including only patients on lithium at SGLT2i initiation ( n = 22) or who had > 1 year of SGLT2i use ( n = 29) showed similar, though non‐significant, changes in slopes. Conclusion SGLT2i treatment was associated with a significant improvement in eGFR trajectory in patients with mood disorders who received long‐term lithium therapy. These findings suggest a potential role for SGLT2is in mitigating lithium‐associated kidney dysfunction and highlight the need for randomized controlled trials in this population.

Abstract Introduction Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly prescribed for weight management. Although generally well-tolerated, these agents may alter the pharmacokinetics of concurrently administered medications. Case Presentation A 23-year-old male with schizoaffective disorder, bipolar type, developed lithium toxicity shortly after switching from semaglutide to tirzepatide. While taking semaglutide, the patient was started on lithium and titrated to 1800 mg nightly, corresponding to a level of 0.9 mEq/L. Four days after his first dose of tirzepatide, he reported early symptoms of potential lithium toxicity, which progressed significantly after the second dose. Symptoms corresponded to a 15-hour post-dose level of 1.7 mEq/L, despite no changes in renal function, hydration status, or other concurrent medications. Management with intravenous fluids was sufficient, and lithium dose reduction prevented future toxicity. Discussion Application of the Drug Interaction Probability Scale suggests a probable interaction between tirzepatide and lithium. The interaction might be mediated through delayed gastric emptying or other pharmacokinetic changes. Limited reports of GLP-1-modulating agents associated with lithium toxicity have been published and may be an underrecognized phenomenon. To date, no pharmacokinetic studies have been published evaluating this potential drug-drug interaction. Although many other medications seem to be at risk for decreased absorption, tirzepatide may enhance the absorption of lithium. Conclusion Clinicians should be vigilant when initiating or switching GLP-1-modulating agents in patients receiving lithium. Pharmacokinetic studies are needed to clarify the mechanism of this interaction. Until more is known, increased monitoring of lithium levels is warranted, with initiation of a GLP-1-modulating agent, a dose change, or switching to another agent.

Background: Clozapine is the preferred medication for treatment-resistant schizophrenia with therapeutic drug monitoring (TDM) suggested to mediate its safe and effective use. However, clozapine TDM is not a ubiquitous element of care in clinical practice. Understanding the current state of clinicians' perceptions of and barriers to clozapine TDM is a crucial step in improving its use. Methods: A survey related to the use, perceptions, and barriers of clozapine TDM was distributed across multiple national organizations in the United States, representing several disciplines. Results: Most of the 190 respondents were consultants or attending physicians (42.5%) or pharmacists (52.3%). Nearly 80% of respondents had ordered clozapine level measurements in the year before completing the survey but identified slow turnaround time (TaT) as an important barrier; 73.5% of respondents noted that level measurements were performed at an offsite laboratory. Although 86.8% agreed that clozapine levels should be checked once an initial target dose was reached, less than half would subsequently order clozapine level measurements routinely, unless clinical factors such as nonadherence (96.5% agreement), new interaction (94.5% agreement), or change in smoking status (94.5% agreement) occurred. More pharmacists than prescribers indicated confidence in interpreting and clinically applying clozapine TDM results (84.6% versus 70.1%, P = 0.024), with a similar finding between the groups regarding faster clozapine TDM TaT, resulting in improved patient safety (89.0% versus 68.7% agreement, P = 0.003). In addition, more pharmacists would also conduct clozapine TDM in the setting of an acute inflammatory or infectious process (84.9% versus 61.2%, P = 0.002). Conclusions: These data provide insights into clozapine TDM perception, availability, TaT, and barriers. Further research is required to assess whether a faster TaT and more frequent clozapine TDM positively influence patient outcomes from a safety and effectiveness perspective.