Combination therapy with beta-adrenergic blockade and amlodipine as second line treatment in essential hypertension.

In hypertension both beta-blockers and calcium antagonists are drugs with proved efficacy. Because only half the patients respond to a single drug, even at full dosage, a second hypotensive agent is frequently required to obtain adequate blood pressure control. The combination of a dihydropyridine calcium antagonist and a beta-blocker can be justified by their different mechanisms of action. A randomised double blind parallel group study versus placebo was performed, in order to assess the efficacy of atenolol combined with amlodipine in the treatment of stage I-II essential hypertension not controlled by atenolol alone. Twenty-four-hour arterial blood pressure monitoring showed that amlodipine added to atenolol produced a statistically significant reduction of blood pressure values compared with placebo in patients whose blood pressure was not controlled by atenolol alone. Blood pressure circadian rhythm was unchanged. The reduction of side-effects, obtained by adding a dihydropyridine derivate to a beta-blocker, confirms the effectiveness of this combination.