Major
Ciprofloxacin × Glibenclamide
Fluoroquinolone antibacterials×Oral hypoglycemic agents. Sulfonylureas
Mechanism
Ciprofloxacin disrupts insulin secretion from pancreatic β-cells and concurrently inhibits CYP2C9 – the glibenclamide metabolic route. Glibenclamide plasma levels rise, intensifying its hypoglycaemic effect. FDA warning was issued in 2018.
Symptoms
Severe hypoglycaemia: sweating, tremor, hunger, tachycardia, confusion; severe cases progress to seizures and coma. Symptoms appear within 1–7 days, especially in older patients and chronic kidney disease.
Management
Avoid the combination. Alternative antibiotics: a cephalosporin or fosfomycin (no CYP2C9 effect and no β-cell impact). If ciprofloxacin is needed, monitor glucose 4 times daily and warn the patient about hypoglycaemia signs.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.