Differences in response of black hypertensives to alpha vs. beta adrenergic antagonists: preliminary findings

We tested our clinical impression that black hypertensives in our clinic population responded better to alpha-adrenergic blocking agents (clonidine and prazosin) than to beta-adrenergic blockers (atenolol, nadolol and propranolol). Compared to no effect from eight weeks of therapy with beta-blockers, clonidine significantly decreased erect mean arterial pressure (MAP) when assessed weekly for four weeks (p = 0.027 to 0.046). However, the decrease in supine MAP was not significant. The effects of prazosin were more modest. Supine MAP was significantly less than with beta-blockade (p = 0.032) at two weeks but not at four weeks and decrements in erect MAP were not significant. In this preliminary study, black hypertensives appeared to be more responsive to alpha-adrenergic antagonists than to beta-blockers, with clonidine more effective than prazosin. Elucidation of possible mechanisms of the difference and of its clinical importance warrant further study.