In a double-blind cross-over multicentre study lasting for 16 weeks, the
antihypertensive effect of
atenolol (100 mg once a day) was compared with that of
methyldopa (250 mg thrice a day) in 48 patients with mild to moderately severe
hypertension. At the end of the trial,
atenolol was superior to
methyldopa in achieving clinically relevant BP levels, less than 150/95 mmHg (p less than 0.001), and in respect to patients'
drug preference (p less than 0.04). The BP levels after the first 2 weeks of treatment with either
drug were identical but, in contrast to
methyldopa,
atenolol caused further significant reduction in BP during the following 4 weeks. This finding implies that one should hesitate to start additional
therapy until after at least six weeks of
atenolol treatment, whereas no further reduction in BP can be expected after the first 2 weeks of treatment with
methyldopa. Two patients had to be withdrawn from the study during treatment with
atenolol, as they developed severe
bradycardia and dyspnoea, respectively. Other side-effects were few and of minor clinical importance.