The role of amiloride in managing patients with lithium-induced nephrogenic diabetes insipidus

Abstract

Background: Despite lithium being a highly effective drug, it is commonly associated with inducing nephrogenic diabetes insipidus(NDI) in a high number of patients. In this case report we describe the successful use of amiloride as an effective means to manage and minimise NDI occurring in patients while they are on lithium therapy.Clinical details: The patient had been taking lithium for management of her bipolar disorder for approximately 5 years. While on this medication the patient suffered from acute kidney impairment, hypernatraemia, reduced urine osmolality, increased plasma osmolality, polyuria, polydipsia and severe dehydration. These clinical results were consistent with an adverse reaction known as NDI acquired from long-term lithium use and fluid restriction.Outcomes: Lithium was ceased on day two of admission. Intravenous fluid replacements were provided until the patient's renal function and sodium levels returned to normal. Once the patient was symptomatically stable, lithium was reintroduced at initiating dosage levels concomitantly with amiloride with aims of reversing the concentrating defect and preventing this side effect from occurring again. The patient was discharged 15 days later.Conclusion: In most cases NDI is reversible with the cessation of lithium. However, a subset of the mental health population is resistant to other forms of therapy, leaving lithium as their only option to successfully manage their mood disorder. For patients who suffer from mental health disorders, the literature has found that amiloride can be an effective means to restore a patient’s impaired urine concentrating ability.