Noun
an acute blood disorder (often caused by radiation or drug therapy) characterized by severe reduction in granulocytes
Source: WordNetAdverse hematologic effects Hematologic effects, such as neutropenia, agranulocytosis and other blood dyscrasias, have occurred during therapy with ACE inhibitors, especially in patients with additional risk factors (see Warnings). Source: Internet
The most dangerous side effect is agranulocytosis (1/250, more in PTU). Source: Internet