Hypernatremia secondary to soluble paracetamol use in an elderly man: a case report

INTRODUCTION: Soluble (effervescent) paracetamol is routinely given to elderly patients for convenience. A daily dose of 4 gm in this soluble formulation can contain up to 8.7 gm of sodium chloride, which exceeds the threshold recommended by the World Health Organization. Hypernatremia secondary to soluble paracetamol has rarely been reported. We describe an elderly patient who developed hypernatremia shortly after taking soluble paracetamol. CASE PRESENTATION: A confused 89-year-old man with back pain secondary to metastatic prostatic carcinoma was prescribed soluble paracetamol. Ten days later, his serum sodium concentration had increased from 142 mmol/L to 165 mmol/L. Soluble paracetamol was withdrawn shortly before he died, and was believed to have contributed to his hypernatremia. CONCLUSION: Hypernatremia is associated with high morbidity and mortality. Clinicians should be aware of the high sodium chloride content in soluble paracetamol, which can precipitate hypernatremia in elderly patients with impaired renal function.