Drug General Information (ID: DDI093YEQB)
Drug Name			Metformin		Drug Info		Vancomycin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antidiabetic Agents				Antiinfective Agents
Structure

Mechanism of Metformin-Vancomycin Interaction (Severity Level: Moderate)
Competitive inhibition of renal tubular secretion Click to Show/Hide Mechanism Graph
Drug Name		Metformin				Vancomycin
Mechanism		Metformin				Competitive inhibition of renal tubular secretion of metformin
Key Mechanism Factor 1
		Factor Name		Renal tubular secretion
		Factor Description		Renal tubular secretion allows selective transfer of substances from the blood around the capillaries into the renal tubules via filtrate. Drug excretion may be reduced when two drugs compete for renal tubular secretion.
Mechanism Description		Decreased elimination of Metformin caused by Vancomycin mediated competitive inhibition of renal tubular secretion

Recommended Action
Management		If vancomycin and metformin must be used together, particularly slow and cautious titration of metformin dosage is recommended. The maximal dose of metformin probably also should be reduced until further information about this interaction is available. Patients should be advised to monitor their blood glucose and to promptly notify their physician if they experience possible signs of lactic acidosis such as malaise, myalgia, respiratory distress, hyperventilation, slow or irregular heartbeat, somnolence, abdominal upset, or other unusual symptoms.

References
1	Product Information. Glucophage (metformin). Bristol-Myers Squibb, Princeton, NJ.
2	Somogyi A, Stockley C, Keal J, Rolan P, Bochner F "Reduction of metformin renal tubular secretion by cimetidine in man." Br J Clin Pharmacol 23 (1987): 545-51. [PMID: 3593625]