The Action of Pseudoephedrine Upon the Kidney.

Abstract

It has been shown¹ that pseudoephedrine has a blood pressor effect about half as great as ephedrine, and that its effect on the peripheral vessels is opposite to that of ephedrine. Pseudoephedrine dilates the peripheral vessels.² Hence it was thought possible that pseudoephedrine might act as a diuretic.

A series of experiments upon 25 dogs was undertaken to see if the dilation of the peripheral vessels applied to the gross effect of pseudoephedrine upon the kidney in the intact animal; moreover whether there was an increase in the secretion of urine, and its relationship to blood pressor effects. The effects of repeated injections were also studied.

Luminalized dogs were treated intravenously with doses of pseudoephedrine hydrochloride ranging from 1 to 11.8 milligrams per kilo. The carotid blood pressure, kidney volume, and urine flow were all carefully observed by ordinary methods involving no special technique. It was found that injections of one or two milligrams of the drug cause a rise in blood pressure of 8 to 22 mm. Hg., lasting 6 to 40 minutes. Larger doses of 5 to 11 milligrams cause a fall in blood pressure of 16 to 22 mm. Hg. Intermediate doses and repeated injections of small doses eventually cause a fall in blood pressure, which may be preceded by injections causing a primary fall of a few mp. and then a rise of blood pressure. A second injection of an average dose of 4 mgm. produced as great a fall as 35 mm. Hg.

The kidney volume follows the blood pressure tracing very closely. A rise in blood pressure causes an increase in kidney volume and a fall is followed by a contraction of the kidney.