Safety of digoxin questioned
OSLO, NORWAY. Digoxin (digitalis, Lanoxin) is widely used in the treatment of heart failure in order to increase the force of heart muscle contractions (positive inotropic effect) and reduce heart rate (ventricular rate). This results in an increase in exercise capacity, but digoxin treatment has no effect on overall survival in heart failure patients. This raises the question, "Are the beneficial inotropic benefits of the drug counterbalanced by serious adverse effects?"

A team of American, Norwegian and Swedish researchers now provides a preliminary answer to this question. Their study involved 7329 participants in the SPORTIF III and IV trials aimed at comparing the effectiveness of the anticoagulants warfarin (Coumadin) and ximelagatran in afib patients. About 53% of participants were on digoxin throughout the study.

The researchers found a higher mortality (6.5%) in the digoxin group than in the group not using digoxin (4.1%). After adjusting for confounding variables, they conclude that digoxin users have a 53% (relative) higher mortality than do non-users. They suggest that in heart failure patients the adverse effects are counterbalanced by the positive inotropic effect, whereas in AF patients, who do not benefit from the inotropic effect, the adverse effects of digoxin dominate and lead to the 53% relative increase in mortality among users.

Gjesdal, K, et al. Digitalis: a dangerous drug in atrial fibrillation? Heart, Vol. 94, 2008, pp. 191-96

Editor's comment: In my 2001 book "Lone Atrial Fibrillation: Towards A Cure" I called digoxin "the medicine from hell" and warned that it should never be used by lone afibbers as it has been found to increase episode frequency and promote the conversion of paroxysmal afib to the permanent version. The above finding that digoxin also increases mortality among afibbers only strengthens my conviction that this is indeed a drug to be avoided.