Clozapine-Associated Kidney Injury Complicated by Lithium Toxicity: A Case Report and Literature Review

Risks and benefits of clozapine and lithium co-prescribing: A systematic review and expert recommendations

OBJECTIVES

To identify the risks and benefits of clozapine‑lithium co-prescription.

METHODS

Articles published in English or French were identified with a MEDLINE, Web of Sciences and PsycINFO search, from inception through January 2023, using the term 'clozapine' in combination with 'lithium'. Data were synthesized narratively.

RESULTS

Of the 67 articles included in the review, more than half (n = 38, 56.7 %) were focused on clozapine-related blood dyscrasia. A body of evidence drawn from case reports and retrospective chart studies highlights the potential benefits of lithium prescription for clozapine-related neutropenia, since this strategy may avoid clozapine discontinuation or allow its rechallenge. The most documented adverse drug reactions (ADRs) associated with clozapine‑lithium co-prescription are neurotoxic events, which may be prevented or detected early by clinical, electroencephalographic and therapeutic drug monitoring. Causality assessment cannot be established for other reported ADRs occurring during clozapine‑lithium co-prescription. The benefits of the combined prescription on psychotic and/or mood symptoms are poorly documented.

CONCLUSION

The risks and benefits of clozapine‑lithium co-prescription require further exploration as the combination might significantly contribute to reducing underprescription or premature discontinuation of clozapine.

Psychotropic Drugs and Adverse Kidney Effects: A Systematic Review of the Past Decade of Research

BACKGROUND AND OBJECTIVE

Psychotropic drugs are a heterogenous group of treatments prescribed for many psychiatric disorders, often for long periods. Their effects on the kidney and its functioning are complex and a source of significant research and debate. This article aims to review recent evidence of the acute and chronic kidney adverse events of diverse psychotropes.

METHODS

A systematic search of randomized controlled trials and large observational studies (n ≥ 100) reporting the effects of psychotropic drugs on the kidney was conducted. The MEDLINE, PsycInfo, and EMBASE databases from 2011 to 2021, inclusive, were broadly searched with few restrictions and no prespecified outcomes. Two or more independent reviewers assessed and summarized all eligible studies, including risks of bias and levels of evidence.

RESULTS

In all, 1999 abstracts were screened for eligibility and 47 articles were included, which examined lithium (33), antiepileptics (10), antipsychotics (13), and antidepressants (9). No studies examining kidney adverse effects of other psychotropes, such as benzodiazepines, met inclusion criteria. Study populations were adult (8), geriatric (9), and mixed (30). Lithium was almost unanimously associated with (1) chronic kidney disease and (2) nephrogenic diabetes insipidus in methodologically diverse studies. The most supported risk factors for declining kidney functioning with lithium were advanced age, duration of lithium treatment, acute lithium toxicity, female sex, medications with known renal interactions, diabetes mellitus/hyperglycemia, and overall medical comorbidity. Supratherapeutic lithium concentrations are both the causes and consequences of acute kidney injury. Once significant chronic kidney disease has developed, four studies found that replacing lithium with other mood stabilizers does not slow progression, and the evolution to end-stage kidney disease is rare overall with modern practices. Compared to lithium, fewer studies examined antipsychotics and antiepileptics but found relatively less direct kidney harms. Antidepressants were not associated with acute or chronic kidney harms.

CONCLUSIONS

Despite the heterogeneity of findings, owing to varying methodologies and research challenges, recent studies strongly suggest that lithium is associated with an increased risk of chronic kidney disease and nephrogenic diabetes insipidus, especially in older adults and long-term lithium users. Clinicians should balance the harms of lithium against its established benefits, and ensure adequate monitoring and management of comorbidities in all patients. Weaker evidence suggests that antiepileptics such as valproate and antipsychotics result in comparatively less harm to the kidney than lithium, but warrant monitoring because of multiple direct and indirect mechanisms for potential kidney adverse events. Antidepressants do not have clear kidney adverse effects and appear safe (though potentially less effective) in the setting of kidney disease. Other classes of psychotropic drugs have received little research interest. Further research is warranted, particularly into specific antiepileptics and antipsychotics, and careful attention should be paid to mitigating important sources of bias such as confounding by indication.