When a triple regimen (ACE inhibitor or ARB, calcium channel blocker, and thiazide diuretic) fails to achieve the target blood pressure, try adding spironolactone.
Strength of recommendation
C: Based on a high-quality disease-oriented randomized controlled trial.1
Willie S, a 56-year-old man with chronic essential hypertension, has been on an optimally dosed three-drug regimen of an ACE inhibitor, a calcium channel blocker, and a thiazide diuretic for more than three months, but his blood pressure is still not at goal. What is the best antihypertensive agent to add to his regimen?
About 5% to 30% of those being treated for hypertension have resistant hypertension, defined as inadequate blood pressure (BP) control despite a triple regimen of an ACE inhibitor or angiotensin receptor blocker (ARB), calcium channel blocker (CCB), and thiazide diuretic.1,2Guidelines from the Eighth Joint National Committee (JNC-8) on the management of high BP recommend ß-blockers, α-blockers, or aldosterone antagonists (AAs) as equivalent choices for a fourth-line agent. The recommendation is based on expert opinion.3
Earlier hypertension guidelines from the UK’s National Institute for Health and Care Excellence recommend an AA if BP targets have not been met with the triple regimen. But this recommendation is based on lower-quality evidence, without comparison to ß-blockers, α-blockers, or other drug classes.4
More evidence since guideline’s release
A 2015 meta-analysis of 15 studies and a total of more than 1,200 participants (three randomized controlled trials [RCTs], one non-randomized placebo-controlled comparative trial, and 11 single-arm observational studies) demonstrated the effectiveness of the AAs spironolactone and eplerenone on resistant hypertension.5In the four comparative studies, AAs decreased office systolic blood pressure (SBP) by 24.3 mm Hg and diastolic blood pressure (DBP) by 7.8 mm Hg more than placebo. In the 11 single-arm studies, AAs reduced SBP by 22.74 mm Hg and DBP by 10.49 mm Hg.
Another RCT examined the effect of low-dose (25-mg) spironolactone, compared with placebo, in 161 patients with resistant hypertension.6At eight weeks, 73% of those receiving spironolactone reached a goal SBP < 140 mm Hg versus 41% of patients on placebo. The same proportion (73%) achieved a goal DBP < 90 mm Hg in the spironolactone group, compared with 63% of those in the placebo group. Ambulatory BP was also found to be significantly improved among those receiving spironolactone versus placebo, with a decrease in SBP of 9.8 mm Hg and in DSP of 3.2 mm Hg.6
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