The use of centrally acting antihypertensive drugs in patients with renal disease.

Clonidine was given to patients with essential hypertension, renovascular hypertension, and hypertension with parenchymal renal disease. The drug was effective in all groups but was more effective in patients with high plasma renin concentration. Renal function did not deteriorate when the drug was used, and there was an increase in renal blood flow and a small increase in glomerular filtration rate in those with renovascular or essential hypertension. These changes may have been due to falls in plasma renin. Clonidine can be used in patients with renal disease and does not cause worsening of renal function.