Shy-Drager syndrome. Effect of fludrocortisone and L-threo-3,4-dihydroxyphenylserine on the blood pressure and regional cerebral blood flow.

Abstract

In nine cases of Shy-Drager syndrome, the changes in blood pressure and cerebral blood flow on sitting up from a supine position were studied. The influence of fludrocortisone, a synthetic mineralocorticoid, and L-threo-3,4-dihydroxyphenylserine (DOPS), a precursor of norepinephrine, on these changes was examined. On After the initial set of measurements, seven patients were treated with fludrocortisone for two weeks. The fludrocortisone was administered in the morning orally at a daily dose of 0-2 mg in five patients, and 0-1 mg in two patients who showed an elevated diastolic blood pressure to above 90 mm Hg in the supine position at a daily dose of 0-2 mg. Seven patients were treated with DOPS administered orally. It was started at 100 mg in the morning and then increased over two weeks to 200 mg three times a day. After the treatment with each drug the same set of rCBF measurements were carried out at 3 pm as before the treatment. Of nine patients with Shy-Drager syndrome, six had both fludrocortisone and DOPS with an interval of 10 to 14 days in between, one patient each had one of these two drugs, and the remaining patient who had no complaint related to the orthostatic hypotension took neither.For the statistical analyses, both parametric (t test and paired t test) and non-parametric (Wilcoxon rank sum test and others) methods were used. Two-tailed analyses were carried out and the difference was estimated to be significant when the p value was less than 0-05. ResultsIn the supine position, the average mean arterial blood pressure was higher and average rCBF lower in the cases of the Shy-Drager syndrome than in normal controls, but neither

Efficacy of Atomoxetine Versus Midodrine for the Treatment of Orthostatic Hypotension in Autonomic Failure

“…Cerebral blood flow could be preserved with the use of systemic pressor agents, such as midodrine. 30 Indeed, midodrine did not improved OH-related symptoms when the entire cohort was analyzed, however, in our sub-group analysis midodrine improved symptoms in patients who had an increase in seated SBP of at least 15 mm Hg. Atomoxetine, on the other hand, may improve OH-related symptoms not only through its effect on systemic blood pressure but also locally by directly increasing cerebral blood flow.…”

An inverted seated posture decreases elbow flexion force and muscle activation

“…However, empirical evidence of headache and motion sickness experienced by astronauts in a reduced gravity environment may at least partially be attributed to changes in ICP and cerebral blood flow (Kawai et al 2003). Several studies have investigated and reported variations in both absolute (Matsubara et al 1990) and relative distribution (Warkentin et al 1992) of cerebral blood flow during conditions of rapid postural change. A study by Bosone et al (2004) found that 10 min of 30°head down tilt caused significantly increased arterial pressure at the cranial level, due to the development of a hydrostatic pressure gradient between heart and brain levels.…”

Drug Treatment of Orthostatic Hypotension Because of Autonomic Failure or Neurocardiogenic Syncope

“…Uncontrolled studies report increases in standing or sitting BP ranging between 14/7 to 46/27mm Hg in a total of 36 patients with orthostatic hypotension because of autonomic failure (16 with type 2 diabetes mellitus, 9 with multiple system atrophy, 6 with Parkinson's disease and 5 with idiopathic disease). [33,36,37] These results were obtained with fludrocortisone dosages usually between 0.2 and 0.5 mg/day (range 0.1 to 1.0 mg/day). In patients with dysautonomia, midodrine 6.25 to 10mg 4 times daily was more effective than fludrocortisone 0.1 mg/day.…”