Lercanidipine-Induced Hyponatremia in Elderly Patients: A Not-So-Rare Complication.

Hyponatremia, defined as serum sodium concentration below 135 mmol/L, is the most common electrolyte disturbance in the hospitalized geriatric population and is associated with significant morbidity and mortality. While various medications are known to contribute to hyponatremia, calcium channel blockers (CCBs) are not considered. Here we present a case of an elderly patient who developed severe hyponatremia (serum sodium 117 mmol/L). Despite standard interventions in an intensive care setting, the patient's hyponatremia proved resistant to correction. Medication review revealed recent initiation of lercanidipine for hypertension management. Upon discontinuation of lercanidipine, the patient's hyponatremia and confusion resolved. Current NHS guidelines do not recommend routine electrolyte monitoring when prescribing CCBs, unlike recommendations for ACE inhibitors and ARBs. We recommend implementing routine electrolyte monitoring when initiating CCBs in this vulnerable population group to prevent potentially life-threatening complications.