Severe and resistant hypoglycemia associated with concomitant gatifloxacin and glyburide therapy

Severe and resistant hypoglycemia occurred in two patients with diabetes mellitus who were receiving concomitant gatifloxacin and glyburide. An 84-year-old woman treated with glyburide for type 2 diabetes mellitus experienced, for the first time, a severe episode of hypoglycemia after 2 days of gatifloxacin 400 mg/day for nonproductive cough. Her blood glucose level on hospital admission was 28 mg/dl. Gatifloxacin and glyburide were discontinued, and the patient was treated with intravenous dextrose infused over 36 hours. Glyburide was restarted before her discharge, with no recurrence of hypoglycemia. A 79-year-old man with type 2 diabetes mellitus treated with glyburide was prescribed gatifloxacin 400 mg/day for pneumonia. After 1 day of therapy, the patient was admitted to the emergency department in a coma. His blood glucose level was 18 mg/dl. Despite discontinuation of gatifloxacin and oral hypoglycemic therapy, hypoglycemia was reversed only after administration of multiple boluses of intravenous dextrose, followed by intravenous dextrose infused over 48 hours. On hospital day 7, gliclazide and levofloxacin were started; the patient experienced no recurrence of hypoglycemia and was discharged on day 10. Several cases of severe and resistant hypoglycemia associated with gatifloxacin therapy have been reported in the recent literature. Although the exact mechanism is not fully understood, it may be linked to a gatifloxacin-induced closing of the adenosine 5'-triphosphate-sensitive potassium channels in the pancreatic beta cells, leading to insulin secretion. The onset of hypoglycemia in relation to the start of gatifloxacin suggests that the drug precipitated this adverse event. Patients receiving oral hypoglycemic agents are at greater risk of experiencing gatifloxacin-induced hypoglycemia than patients not receiving these agents. Clinicians should be aware of this potentially life-threatening adverse event and monitor blood glucose levels in all patients receiving concomitant oral hypoglycemic agents and gatifloxacin.