Forbetes XR Drug Interactions

Glyburide: The single dose nature of this study and the lack of correlation between glyburide blood levels and pharmacodynamic effects, makes the clinical significance of this interaction uncertain.
Furosemide: No information is available about the interaction of Metformin and furosemide when coadministered chronically.
Nifedipine: Nifedipine appears to enhance the absorption of Metformin. Metformin had minimal effects on nifedipine.
Cationic drugs: Cationic drugs (e.g., amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin) that are eliminated by renal tubular secretion theoretically have the potential for interaction with Metformin by competing for common renal tubular transport systems. Although such interactions remain theoretical, careful patient monitoring and dose adjustment of FORBETES 500 XR and/or the interfering drug is recommended in patients who are taking cationic medications that are excreted via the proximal renal tubular secretory system.
Other: Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. These drugs include the thiazide and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blocking drugs, and isoniazid. When such drugs are administered to a patient receiving FORBETES 500 XR, the patients should be closely observed for loss of blood glucose control. When such drugs are withdrawn from a patient receiving FORBETES 500 XR, the patient should be observed closely for hypoglycemia.
Metformin is negligibly bound to plasma proteins and is, therefore, less likely to interact with highly protein-bound drugs such as salicylates, sulfonamides, cloramphenicol, and probenecid, as compared to the sulfonylureas, which are extensively bound to serum proteins.