Capecitabine-Induced Hyperosmolar Hyperglycemic State

Abstract

Abstract Capecitabine is an orally administered prodrug of 5-fluorouracil (5-FU) which is often used for treatment of solid tumour cancers such as breast cancer and gastrointestinal tumours. Common adverse effects include nausea, diarrhea, anorexia and erythrodysthesia (hand-foot syndrome). However, there have been case reports of metabolic disturbances linked to capecitabine including hyperlipidemia, and less commonly, hyperglycemia. We report a case of a new diagnosis of persistent diabetes mellitus following an acute presentation of hyperosmolar hyperglycemic syndrome (HHS) subsequent to treatment with the chemotherapy agent, capecitabine. A 72 year old female with a history of metastatic breast cancer was admitted to hospital for management of hyperglycemic hyperosmolar state (HHS) after bloodwork from her family doctor revealed an elevated random blood glucose (40.2 mmol/L). Leading up to her presentation, the patient had completed 7 cycles of capecitabine treatment for her breast cancer. Prior to her capecitabine treatment, the patient did not have a history of diabetes mellitus. However, on admission, her hemoglobin A1C (HbA1C) was found to elevated into the diabetic range. Offending medications were considered and given the temporal dysglycemia following the patient’s chemotherapy regimen, capecitabine was thought to be a probable offending agent. The patient was acutely treated for HHS, and eventually transitioned to a basal-bolus insulin regimen at discharge. Her capecitabine was held pending review with her oncology team and she was closely followed up by her family doctor. The patient’s insulin regimen was ultimately titrated down to basal insulin only. Given the increasing use of capecitabine therapy in breast cancer, it is important to recognize the risk of hyperglycemia and hyperglycemic emergencies as a potential adverse effect of this treatment. It highlights the need to ensure that blood glucose is monitored throughout treatment to prevent hyperglycemic emergencies.