Endocrine Abstracts

Introduction: Hyponatraemia is defined as serum sodium concentration <135 mmol/l. It is the most common electrolyte disorder encountered in clinical practise (1). Proton pump inhibitors (PPI’s) are commonly prescribed in the UK, and the indication and duration of treatment is often not reviewed.

Methods: A retrospective audit was performed of patients admitted to The Great Western Hospital (GWH) with a serum sodium of 127 mmol/l or less on admission, over a three month period. The aim was to identify prescribed medications that may be contributing to the hyponatraemia.

Results: 75 patients were included in the audit; 27 male (36%) and 48 female (64%). The mean age was 75 years (range 37–94 years). All patients had a serum sodium of 127 mmol/l or less on admission: mean 122 mmol/l and range 108 to 127 mmol/l. 57% of patients had hyponatraemia on more than one occasion in the 12 months prior to admission. 77% of patients were found to be taking prescribed medications which can result in hyponatraemia. These medications belonged to four main groups: diuretics, anti-depressants, anti-epileptics and proton pump inhibitors. Some patients were taking medications from more than one group. The most commonly prescribed medication was PPI’s which 48% of patients were taking on admission. 29% of patients were taking diuretics, 25% anti-depressants and 11% anti-epileptics.

Discussion: This audit clearly demonstrates that drugs may be a contributory factor in the development of hyponatraemia. There are often alternatives, for example H2 receptor antagonists rather than PPIs, and clinicians should consider these in patients at risk of hyponatraemia. 57% of patients audited had a previous diagnosis of hyponatraemia suggesting we may be missing opportunities to review prescribed medications.