Effects of benzothiazepine derivative (CRD-401) on blood pressure, excretion of electrolytes, and plasma renin activity.

A benzothiazepine derivative, CRD-401, was administered orally in a dosage of 60 to 120 mg/day to 14 patients with various renal diseases. The systolic pressure was lowered slightly in some cases after administration of CRD-401. Urine volume and urinary excretion of electrolytes were increased by the drug in most patients except those with severe renal dysfunction. The plasma renin activity was increased to about twice the premedication value in most patients. Although the mechanism of increasing action of CRD-401 on plasma renin activity was assumed to be related to the reabsorption capacity of renal tubules for electrolytes, some questions still remain unanswered. The mechanism of this drug action, therefore, could not be elucidated completely in this study.