Lithium Toxicity in Older Adults: a Systematic Review of Case Reports.

BACKGROUND AND OBJECTIVES: Despite concerns regarding the vulnerability of older adults to lithium toxicity, this has not been well studied. This literature review aims to characterize the nature of lithium toxicity in older adults, the doses and serum lithium levels associated with toxicity, as well as its clinical and laboratory manifestations, precipitating factors, management and outcome.

METHODS: A systematic 10-year search of English articles was conducted using Ovid Medline, Embase Classic + Embase, Cochrane Central Register of Controlled Trials and PsycINFO. All studies on lithium toxicity in elderly (aged ≥ 65 years) where the dose of lithium or serum lithium level was clearly described, were included.

RESULTS: There were no clinical trials or cohort studies found. The search identified 38 cases of lithium toxicity in older adults with a mean age of 71.4 years (SD = 5.53). Mean dose of lithium was 675.4 mg/d (SD = 200.66), and mean toxic serum concentration was 2.55 mmol/L (SD = 2.22). Manifestations varied, with neurotoxicity being the most common, followed by renal and cardiovascular toxicity. Polypharmacy (63.2%) and medical comorbidity (76.3%) were common. Intravenous hydration and hemodialysis were widely used for treatment with good effect. Most patients recovered fully, and only one patient died despite treatment.

CONCLUSION: In published case reports, the lithium dose was higher than recommended for older adults. Polypharmacy and comorbidities appeared to be important precipitating factors of lithium toxicity. Regular monitoring of serum lithium concentrations and appropriate caution should be exercised, even when serum lithium concentrations are within reported therapeutic levels.