Gefitinib

Abstract

Hyponatraemia: case report A 65-year-old man developed hyponatraemia during treatment with gefitinib for metastatic non-small cell lung cancer. The man was diagnosed with stage IVB metastatic non-small cell lung cancer with EGFR-positive mutation and received treatment with oral gefitinib 250 mg/day. He had a medical history of coronary artery disease and diabetes, and was an ex-smoker. His other medications included metoprolol, glipizide, metformin and aspirin. Three weeks after initiation of gefitinib, he presented to a hospital in India with acute onset drowsiness and generalised weakness. He was afebrile and had a BP of 150/98 mm Hg and pulse rate of 96/min. General examination was unremarkable, except for mild pallor. Also, no significant abnormalities were noted in systemic examination and head CT scan was unremarkable. Laboratory investigations showed decreased Hb, MCV, serum sodium, urine sodium, serum osmolarity and HDL, and increased SGOT, SGPT, triglycerides and LDL. Apart from severe hyponatremia (grade III/IV), all other laboratory investigations revealed no significant abnormality. The man received treatment with sodium-chloride [hypertonic saline] and a possibility of severe hyponatremia secondary to gefitinib was considered. Thereafter, treatment with gefitinib was discontinued and at day 3 of hospitalisation as significant improvement in consciousness level was noted. Also, at the end of one week, his serum sodium level normalised and he was asymptomatic. Four weeks later, gefitinib was restarted at a decreased dose of 125 mg/day due to an increase in tumour burden. However, at one month follow-up, he developed grade I asymptomatic hyponatremia [final outcome not stated]. As per Naranjo scale, gefitinib and hyponatremia showed a probable relation.