8 known interactions • 2 major • 4 moderate • 2 minor
Always disclose all medications to your healthcare providers — prescription medicines, OTC medications, vitamins, and herbal supplements. This list may not include every possible interaction. Use our Medicine Interaction Checker to screen your complete medication list.
Potentially life-threatening or causing permanent damage. Avoid combination.
May worsen condition or require dose adjustment. Monitor closely.
Usually limited clinical effect. Manage with routine monitoring.
Iodinated contrast dye
Stop metformin before and 48 hours after contrast dye procedures due to lactic acidosis risk.
Alcohol
Heavy alcohol use increases risk of lactic acidosis. Avoid excessive alcohol.
Topiramate
May increase metformin levels and risk of lactic acidosis.
Cimetidine
Increases metformin plasma concentration by 40–60%.
Furosemide
May increase metformin levels.
Carbonic anhydrase inhibitors (acetazolamide)
Increased risk of lactic acidosis.
Insulin
Additive hypoglycemic effects; monitor blood glucose.
Sulfonylureas (glipizide, glyburide)
Additive blood glucose lowering; may require dose adjustment.
Always ask your pharmacist about potential interactions with food, alcohol, and supplements specific to Metformin. Some medicines have significant interactions with grapefruit juice, high-fat meals, dairy products, or vitamin K-rich foods.