The selectivity of single oral doses of
xamoterol, 200 mg,
prenalterol, 50 mg, and
salbutamol, 8 mg, was compared in eight healthy male volunteers by measuring their effects on sleeping heart rate, supine heart rate, blood pressure, forearm blood flow, finger
tremor, and exercise heart rate in the presence and absence of the specific beta 2-adrenoceptor antagonist
ICI 118,551, 25 mg.
Xamoterol, 200 mg, increased sleeping heart rate and systolic blood pressure, decreased exercise heart rate, and had no effect on diastolic blood pressure, forearm blood flow, or finger
tremor. The concurrent administration of
ICI 118,551, 25 mg, did not alter these results. Supine heart rate was increased by
xamoterol and did not differ from that for
xamoterol with
ICI 118,551.
Prenalterol, 50 mg, increased sleeping heart rate, supine heart rate, systolic blood pressure, forearm blood flow, and finger
tremor, decreased diastolic blood pressure, and had no effect on exercise
tachycardia. The concurrent administration of
ICI 118,551 with
prenalterol reduced the increase in sleeping heart rate, supine heart rate, and forearm blood flow, and reduced the fall in diastolic blood pressure caused by
prenalterol alone. The increase in finger
tremor following
prenalterol with
ICI 118,551 tended to be less than that following
prenalterol.
Salbutamol, 8 mg, increased sleeping heart rate, supine heart rate, systolic blood pressure, forearm blood flow, finger
tremor, and exercise heart rate, and caused a fall in diastolic blood pressure. When
salbutamol, 8 mg, was administered with
ICI 118,551, 25 mg, the only changes detected were a small initial increase in finger
tremor and a small rise in diastolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)