CARBAMAZEPINE-INDUCED HYPONATREMIA: A CLINICAL PHARMACIST INTERVENTION

Background: Background: Carbamazepine is an effective antiepileptic drug but is associated with rare adverse effects such as hyponatremia, particularly due to its role in potentiating antidiuretic hormone release, leading to water retention and dilutional hyponatremia. Case Presentation: A 58-year-old man with a history of long-standing carbamazepine therapy for seizure disorder had presented to hospital with a symptom complex of confusion, drowsiness, and fatigue. Laboratory investigations revealed severe hyponatremia (serum sodium, 118 mEq/L) in keeping with Syndrome of inappropriate antidiuretic hormone secretion (SIADH). The clinical pharmacist considered carbamazepine to be the inciting agent and recommended its stopping, along with fluid restriction and correction with hypertonic saline. Subsequently, the patient stabilized and was put on levetiracetam. Intervention: Clinical pharmacists were instrumental in detection of the adverse drug reaction, in optimizing the therapy, and in continuous monitoring leading to resolution of symptoms and normalization of the electrolyte profile. Outcome: Following discontinuation of carbamazepine and supportive management, the patient normalized sodium levels and symptomatically started resolving within days. No further complications were reported. Conclusion: This case imparts the importance of recognizing carbamazepine-induced hyponatremia and the pivotal involvement of clinical pharmacists on the detection, management, and prevention of adverse drug reactions. The multidisciplinary approach benefits both patient safety and clinical outcomes. Keywords: Carbamazepine, Hyponatremia, SIADH, Clinical Pharmacist, Adverse Drug Reaction, Antiepileptic Drugs