How do antiarrhythmics, quinidine affect serum digoxin concentrations?
Antiarrhythmics can increase serum digoxin concentrations. For example, quinidine decreases tissue binding of digoxin, leading to smaller volume of distribution and higher serum digoxin concentrations. Quinidine may also interfere with digoxin secretion by inhibiting P-glycoprotein in the kidney and intestine, resulting in an increase in serum digoxin concentrations.
Doering W. Quinidine-digoxin interaction: pharmacokinetics, underlying mechanism, and clinical implications. New Engl J Med. 1979;301:400-404
Contributed by: Kush Patel, MD
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