Time-course changes in blood pressure, urinary excretion of norepinephrine and dopamine after administration of fusaric acid in a single dose in elderly hypertensive patients

Time-course changes in blood pressure, urinary norepinephrine and dopamine excretion after administration in a single dose of fusaric acid calcium salt were examined in 8 elderly hypertensive patients. Eight elderly hypertensive patients served as controls receiving placebo administration in a single dose. The dose of fusaric acid calcium salt ranged from 5.1 mg/Kg to 6.0 mg/Kg. The results obtained are as follows: 1) Both systolic and diastolic blood pressure showed a significant reduction in fusaric acid calcium salt group, the lowest value of systolic blood pressure being observed from 4 to 8 hrs. and that of diastolic blood pressure being observed from 4 to 6 hrs. after administration of this agent, respectively. Systolic blood pressure returned more slowly to the level before fusaric acid calcium salt administration than diatolic blood pressure did. In placebo group, however, no significant reduction of both systolic and diastolic blood pressures was noted. 2) In fusaric acid calcium salt group, norepinephrine excretion in the urine did not show a diurnal change. In placebo group, however, a tendency of diurnal change was noted. These results would suggest that noepinephrine synthesis might be inhibited temporalily by fusaric acid calcijm salt. 3) In fusaric acid calcium salt group, dopamine excretion in the urine did hardly show a diurnal change. In placebo group, however, a fairly evident diurnal change was observed. The interpretation of these results seems to be difficult in the present state of knowledge of the action of fusaric acid calcium salt in humans.