Urinary norepinephrine excretion in elderly hypertensive patients during administration of fusaric acid

The urinary norepinephrine excretion during fusaric acid calcium salt administration was examined in 5 elderly hypertensive patients by double blind cross-over method. The average daily excretion of the last 5 days during fusaric acid calcium salt or placebo administration of 5 weeks' duration was compared in each patient. In 4 patients except for one, the average daily urinary excretion of norephinephrine during fusaric acid calcium salt administration showed an increase, being highly significant (p less than 0.01) statistically, when compared with that during placebo administration, the latter being essentially unchanged. In the one patient, however, the average daily urinary excretion of norepinephrine was significantly higher during placebo administration than that during fusaric acid calcium salt administration. The relationship between the changes in the average daily urinary excretion of norepinephrine and those in blood pressures seemed to be not consistent. The mechanism which brought about an increased norepinephrine excretion in the urine of the hypertensive patients is not obscure at present.