Various, available as a generic.
Type 2 diabetes
Off-label use for weight loss
Unclear; increases insulin sensitivity, decreases glucose absorption from GI tract.
Metformin IR (immediate release) supplied as 500 mg, 850 mg, and 1000 mg tablets.
Start with 500 mg QPM (with dinner), titrate gradually up to 850 mg BID with meals.
Metformin SR (slow release) or XR (extended release) supplied in 500 mg and 750 mg strengths.
Start at 500 mg QPM and titrate up to maximum of 2000 mg QPM with dinner.
Common: Diarrhea, nausea, abdominal cramping.
Most serious is lactic acidosis, which is rare.
No significant drug-drug interactions.
Contraindicated for patients with kidney or liver disease.
Excreted unchanged in the urine, no liver metabolism. .