Standards of lithium monitoring in mental health trusts in the UK

Abstract

BackgroundLithium is a commonly prescribed drug with a narrow therapeutic index, and recognised adverse effects on the kidneys and thyroid. Clinical guidelines for the management of bipolar affective disorder published by The National Institute for Health and Clinical Excellence (NICE) recommend checks of renal and thyroid function before lithium is prescribed. They further recommend that all patients who are prescribed lithium should have their renal and thyroid function checked every six months, and their serum lithium checked every three months. Adherence to these recommendations has not been subject to national UK audit.MethodsThe Prescribing Observatory for Mental Health (POMH-UK) invited all National Health Service Mental Health Trusts in the UK to participate in a benchmarking audit of lithium monitoring against recommended standards. Data were collected retrospectively from clinical records and submitted electronically.Results436 clinical teams from 38 Trusts submitted data for 3,373 patients. In patients recently starting lithium, there was a documented baseline measure of renal or thyroid function in 84% and 82% respectively. For patients prescribed lithium for a year or more, the NICE standards for monitoring lithium serum levels, and renal and thyroid function were met in 30%, 55% and 50% of cases respectively.ConclusionsThe quality of lithium monitoring in patients who are in contact with mental health services falls short of recognised standards and targets. Findings from this audit, along with reports of harm received by the National Patient Safety Agency, prompted a Patient Safety Alert mandating primary care, mental health and acute Trusts, and laboratory staff to work together to ensure systems are in place to support recommended lithium monitoring by December 2010.

Evaluation of parathyroid function and mineral metabolism in psychiatric patients using lithium salts

“…Since Li is not bound to serum proteins, it is freely filtered by the kidneys and its elimination depends on the glomerular filtration rate. Consequently, Li blood levels and undesirable effects caused by Li are directly related to renal function (9,10). The participants of this study were assessed by measurements of blood urea and creatinine, which were within normal limits.…”

“…This could lead to a classic PHP and even to a normocalcemic HPT or hypercalcemia without PTH elevation (9,26,27). Both in vitro studies and in vivo studies in healthy volunteers demonstrated direct action of lithium on parathyroid cells in releasing intact PTH (28).…”

“…Li has a very narrow therapeutic window, being clinically effective with plasma concentrations of 0.6-1.5 mEq/L (equivalent to 600-1,500 mg of LC) and producing many toxic effects when above these values, thus justifying the importance of quarterly to semiannual monitoring of the serum levels of patients using Li (8)(9)(10)(11).…”

Endocrine disturbances related to the use of lithium

“…About 95% of the ingested dose is excreted in the urine without undergoing biotransformation. Its half-life is up to 24 hours and may be longer in the elderly (1,3). Approximately 80% of lithium is reabsorbed in the proximal renal tubules.…”

“…Currently, they are available in immediate-and extended-release formulas and are used to treat mania, refractory and recurrent depression and bipolar disorders with reduced morbidity and mortality. Despite recent advances in pharmacological treatment of psychiatric disorders, these salts remain effective and inexpensive alternatives (3,4).…”