Drug General Information (ID: DDI2SOMPU4)
Drug Name			Dofetilide		Drug Info		Metformin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiarrhythmic Agents				Antidiabetic Agents
Structure

Mechanism of Dofetilide-Metformin Interaction (Severity Level: Moderate)
Competitive inhibition of renal tubular secretion Click to Show/Hide Mechanism Graph
Drug Name		Dofetilide				Metformin
Mechanism 1		Dofetilide				Competitive inhibition of glomerular filtration of dofetilide
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 Dofetilide caused by Metformin mediated competitive inhibition of renal tubular secretion
Mechanism 2		Dofetilide				Competitive inhibition of renal tubular secretion of dofetilide
Key Mechanism Factor 2
		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 Dofetilide caused by Metformin mediated competitive inhibition of renal tubular secretion

Recommended Action
Management		The manufacturer recommends that the patient be closely monitored if these drugs are coadministered.

References
1	Product Information. Tikosyn (dofetilide) Pfizer US Pharmaceuticals, Atlanta, GA.