Key result
Fludrocortisone raises resting SBP by ~10 mm Hg and decreases total body noradrenaline spillover.
Why the study?
The role of the sympathetic nervous system in the pathogenesis of mineralocorticoid hypertension in man was unclear.
Does oral fludrocortisone alter haemodynamics and noradrenaline spillover in normal men?
Does oral fludrocortisone alter haemodynamics and noradrenaline spillover in normal men?
Mean Difference: 10
Absolute Event Rate: 115% vs 105%
p-value: p=< 0.01
Fludrocortisone-induced hypertension is associated with decreased total body noradrenaline spillover, suggesting the sympathetic nervous system does not play a major pathogenetic role.
Small study in healthy men is hypothesis-generating; leaves open mineralocorticoid effects on hemodynamics in hypertension.
This study examined haemodynamics and noradrenaline spillover in five normal men before and on day 7 of oral fludrocortisone treatment, 0.3 mg/day. Resting systolic (105 to 115 mm Hg, standard error of the difference +/- 2.0, p < 0.01) and diastolic (65 to 73 mm Hg, +/- 3.0, p < 0.05) blood pressure increased, as did cardiac output, from 5.0 to 5.7 L/min (+/- 0.1, p < 0.01). Calculated total peripheral resistance fell from 21.2 to 20.0 mm Hg/L/min (+/- 0.4, p < 0.05). Fludrocortisone produced a fall in plasma potassium, renin and aldosterone concentrations and haematocrit and a rise in body weight. Cold pressor responses were increased by fludrocortisone, from 7.5 to 20 mm Hg (+/- 3.0, p < 0.01), and forearm vascular resistance rose 12 arbitrary resistance units (R) before and 36 R units after treatment (+/- 5.0, p < 0.01). Total body spillover of noradrenaline was decreased from 9.48 to 7.36 ng/kg/min (+/- 0.86, p < 0.05). There were no changes in forearm noradrenaline spillover at rest or during cold pressor stimulation. It appears unlikely that the sympathetic nervous system plays a major role in the pathogenesis of mineralocorticoid hypertension in man.
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Pirpiris et al. (1994) studied this question. Fludrocortisone vs. Baseline (before treatment) was evaluated on Resting systolic blood pressure (p=< 0.01). Oral fludrocortisone treatment for 7 days in normal men increased resting systolic blood pressure from 105 to 115 mm Hg (p < 0.01) and decreased total body noradrenaline spillover.
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