The drug was found to be safe with no adverse effects on vital signs, ECG or clinical chemistry. 2D M-Mode echocardiography revealed no on left ventricular mass effects, and the small reductions in hemoglobin 14.5 to 14.3 g/100ml in the highest dose group) and hematocrit (from 42.6% to 41.8%) are not regarded as being clinically significant. Furthermore, BRL 49653C was found to be well tolerated over the dose range 0.05-2.0mg bid with an adverse event profile that was similar to placebo both qualitatively and quantitatively.