Effect of oral amrinone on platelet function and survival.

Amrinone is a cardiotonic agent associated with reversible thrombocytopenia in 20% to 50% of patients. The mechanism of thrombocytopenia is not known and it is not clear whether this effect represents a high-frequency idiosyncratic reaction or an overt manifestation of a toxic effect on platelet survival. We prospectively evaluated the effect of oral amrinone on platelet function and survival in seven subjects who participated in a clinical trial of chronic oral amrinone therapy. There was no consistent effect on either platelet function or platelet survival. Data suggest that amrinone does not have a uniform effect on platelet survival and that the development of thrombocytopenia may represent an idiosyncratic reaction.