RT Journal
A1 Leahey EB, Jr, Reiffel JA, Heissenbuttel RH, Drusin RE, Lovejoy WP, Bigger J, Jr
T1 ENhanced cardiac effect of digoxin during quinidine treatment
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 1979
FD May 1
VO 139
IS 5
SP 519
OP 521
DO 10.1001/archinte.1979.03630420015008
UL http://dx.doi.org/10.1001/archinte.1979.03630420015008
AB Quinidine causes an increase in the serum digoxin concentration. Three patients were studied to determine if the increase in serum concentration is paralleled by an increase in the cardiac effect of digoxin. Each patient's clinical condition and serum digoxin concentration were stable when quinidine administration was begun. In all three patients, serum digoxin concentrations increased significantly after beginning quinidine, and decreased when quinidine was discontinued. While taking quinidine, all three patients had ECG findings that suggested enhanced digitalis effect and one patient had clinical evidence of an increased hemodynamic effect. These effects paralleled the increases in serum digoxin concentration. Our findings suggest that the increase in serum digoxin concentration, which occurs after beginning quinidine, is associated with an increase in the effect of digoxin on the heart.(Arch Intern Med 139:519-521, 1979)