SAN FRANCISCO—Spironolactone may significantly reduce ambulatory blood pressure (BP) levels in patients with end-stage renal disease (ESRD), according to a new study presented at the 28th Annual Scientific Meeting of the American Society of Hypertension.

“We found it was quite effective in lowering blood pressure and we think it holds promise,” said investigator Alan Hinderliter, MD, Associate Professor of Medicine at the University of North Carolina, Chapel Hill, N.C. “On average, the increase in potassium was small and decrease in blood pressure was pretty dramatic.”

In most cases, patients with ESRD have uncontrolled hypertension despite treatment with multiple drugs, Dr. Hinderliter said. Spironolactone previously has been shown to be an effective agent for refractory hypertension. However, it has not been extensively studied in patients with ESRD.

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In an open-label study, 11 ESRD patients with refractory hypertension were enrolled at a single dialysis center and were treated with spironolactone 25 mg daily along with their baseline antihypertensive therapy. All patients had an average pre-dialysis systolic BP of 140-180 mm Hg despite taking two or more antihypertensive drugs. The researchers measured 24-hour ambulatory BP and serum potassium at baseline and again after four and 16 weeks of treatment. In addition, the investigators evaluated serum aldosterone, C-reactive protein (CRP), left ventricular (LV) mass, and flow-mediated dilation of the brachial artery (FMD).

Ten of the 11 patients were African Americans and eight were men. The mean age of the patients was 55 years and the mean duration of ESRD was 3.9 years. The median 24-hour ambulatory BP at baseline was 156/84 mmHg and the median serum potassium was 4.6 mmol/L.  

Four patients dropped out of the study early. Two had nausea, one was unable to wear the BP monitor, and one experienced hyperkalemia. Whether the nausea was truly related to the drug is difficult to say, Dr. Hinderliter said.

“Some patients may develop breast tenderness or breast enlargement but we did not see that in our study,” he said.

Spironolactone treatment resulted in a mean decrease of 15/9 mm Hg decrease in 24-hour BP levels at four weeks and a mean decrease of 9/3 mm Hg decrease at 16 weeks. In addition, the researchers found that awake and sleep BP levels were lowered by similar amounts. The mean serum potassium levels were higher by 0.25 mmol/L at four weeks and by 0.4 mmol/L at 16 weeks, but these changes were not statistically significant. Mean serum aldosterone levels rose from 123 to 169 pg/mL, but no changes were observed in CRP levels, LV mass, or FMD.

“I would caution that we can’t make too much out of the data because of the limited number of patients, but it does indicate to us that it is worthwhile studying this [drug] in a larger and more rigorous trial,” Dr. Hinderliter said.