Cupreidine 96'-hydroxycinchonine) is a recently synthesized analog of
quinidine (6'-methoxycinchonine). Previous studies in mice have shown that
quinidine and
cupreidine have equivalent antiarrhythmic potencies, whereas the acute toxicity of
cupreidine is about 50% less than that of
quinidine. Many of the serious adverse effects of
quinidine are due to undesirable cardiovascular properties. We have, therefore, compared the effects of the two drugs on blood pressure, heart rate, and peripheral vasodilation in rats, and on myocardial contractility in isolated rabbit hearts at a series of comparable doses.
Quinidine produces a more marked
bradycardia and depression of blood pressure than does
cupreidine. The vasodilation produced by intraarterial administration of
quinidine was significantly greater than
cupreidine. Furthermore,
quinidine elicited a greater negative inotropic effect.
Cupreidine exhibited a much more favorable hemodynamic profile than
quinidine with regard to the properties that were examined. These results, coupled with the fact that
cupreidine has significant antiarrhythmic activity and a lower acute toxicity profile, suggest that this
drug may be useful in the
therapy of
cardiac arrhythmias.