Captopril and salt subtraction to treat "uncontrollable" hypertension in haemodialysis patients.

Eight patients on chronic haemodialysis for six months to 7 years with hypertension resistant to ultrafiltration and antihypertensive therapy, received Captopril (SQ 14, 225) an orally active inhibitor of converting enzyme. With this therapy, blood pressure was controlled in the 4 patients with the highest plasma renin activity. In the other 4, this treatment had to be supplemented with "isovolumetric salt subtraction", i.e. following conventional dialysis, 1-2 litres of ultrafiltrate were replaced by an equal volume of 5% glucose. The slight hyponatraemia induced by this procedure (plasma sodium 128mmol/L) was well tolerated. This procedure allows the removal of an excess of body sodium and seems to be effective even when conventional ultrafiltration during dialysis has failed. Administration of Captopril either alone or combined with "isovolumetric salt subtraction" induced good control of blood pressure in all 8 patients.