Summary
The effect of clonidine and minoxidil on sympathetic nervous activity has been studied in 10 patients with accelerated or resistant hypertension. Clonidine 150 to 900 µg/day caused a significant decrease in blood pressure of 18.6 mm Hg, of heart rate 16.4 beats/min, or plasma renin activity 1.13 ng/ml·h, and of urinary noradrenaline excretion 11.55 µg/day, and a significant lengthening of the pre-ejection period of 12.4 ms. Minoxidil 5 to 22.5 mg/day caused a further significant decrease in blood pressure of 24.2 mm Hg, and significant increases in heart rate 8.2 beats/min, plasma renin activity 1.68 ng/ml·h, and of urinary noradrenaline excretion 5.0 µg/day, and a significant shortening of the pre-ejection period of 20.6 ms. Neither clonidine nor minoxidil altered plasma dopamine β-hydroxylase activity or the cardiovascular responses to treadmill exercise. It is concluded that clonidine is a useful alternative agent to block a minoxidil-induced increase in sympathetic nervous activity.
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This study formed part of a doctoral thesis by Dr. M. Velasco, submitted to the Universidad Nacional del Zulia, Maracaibo, Venezuela, 1979.
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Velasco, M., Urbina-Quintana, A., Hernández, E. et al. Effect of minoxidil on sympathetic nervous activity in clonidine-treated hypertensive patients. Eur J Clin Pharmacol 20, 259–262 (1981). https://doi.org/10.1007/BF00618775
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DOI: https://doi.org/10.1007/BF00618775