Severe Hypoglycemia From Clarithromycin-Sulfonylurea Drug Interaction

We report two cases of severe hypoglycemia occurring in elderly men with type 2 diabetes who were prescribed clarithromycin for respiratory infections. Both individuals had well-controlled diabetes and mild to moderately impaired renal function. Both individuals were prescribed clarithromycin in identical dosages and both developed severe hypoglycemia within 48 h of starting the antibiotic. Although many drugs have been reported to interact with sulfonylureas causing hypoglycemia, the interaction between clarithromycin and a sulfonylurea has not been previously reported. We discuss the suspected mechanism for this potentially severe reaction which is of concern in the treatment of elderly patients with type 2 diabetes. An 82-year-old white male with a 4-month history of type 2 diabetes was treated with diet and glyburide 5 mg daily. His blood glucose readings were in the low 100s (mg/dl). His comorbidities included atherosclerotic heart disease, hypertension, mild chronic renal failure with a creatinine of 1.6 mg/dl, emphysema, and bladder cancer. In a local emergency department (ED), he was diagnosed with “bronchitis” and prescribed clarithromycin, 1,000 mg daily. He became unresponsive with an Accucheck reading of 24 mg/dl, 48 h after starting clarithromycin. Administration of intravenous …