Bisoprolol is a new highly beta 1-selective beta-
adrenoceptor blocking
drug; it is devoid of intrinsic
sympathomimetic effects. Its haemodynamic effects are those expected from beta 1-blockade, heart rate is reduced at rest and on exercise, cardiac output falls and peripherial resistance is increased. Consequent on the beta 1-selectivity there is much greater inhibition of exercise
tachycardia compared to inhibition of
isoprenaline-induced falls of diastolic blood pressure, in contrast to
propranolol. Studies in asthmatics confirm the selectivity of
bisoprolol.
Bisoprolol has similar solubility in water and organic
solvents and predictably therefore about half is excreted by the kidneys unchanged, half metabolized by the liver. Estimates of half-life average about 10-12 h, this is in accord with the therapeutic efficacy of once daily administration. Therapeutic studies have demonstrated the efficacy of
bisoprolol in
angina pectoris, arrhythmias and
hypertension. Comparative studies against
atenolol and
verapamil in angina suggest similar efficacy. In
hypertension a similar
antihypertensive effect to
nifedipine has been found, while a significantly greater lowering of blood pressure was seen than that obtained with a
diuretic. Some studies have also suggested more consistent
antihypertensive effect from
bisoprolol than
atenolol 24 h after administration. This may have been a dosage phenomenon or reflects the longer plasma elimination half-life of
bisoprolol, and requires confirmation.
Bisoprolol has a favourable side-effect profile.