Spironolactone and Amiloride Effective in Drug-Resistant Hypertension
Older diuretics such as spironolactone and amiloride were found to work best at lowering blood pressure in drug-resistant hypertension (RHTN), according to new analyses from the PATHWAY-2 study. The full data were presented at the European Society of Cardiology (ESC) Congress 2017 in Barcelona, Spain.
Original findings from the Phase 4 PATHWAY-2 study demonstrated that spironolactone was significantly better than other agents at reducing blood pressure in patients with resistant hypertension.
In the study, all patients (n=314) were receiving a standard regimen referred to as the “A+C+D treatment strategy,” which consisted of an angiotensin converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker (ARB) plus a calcium channel blocker (CCB), and a diuretic. Patients stayed on this baseline treatment and were rotated between placebo, bisoprolol, doxazosin, or spironolactone as add-on therapy for four 12-week cycles.
Several sub-studies investigated the superior efficacy of spironolactone in RHTN and whether there was potential benefit with amiloride in the same population. The researchers believe that the underlying cause of RHTN is due to salt retention from overproduction of aldosterone, a salt-retaining hormone. The 2 diuretics proved effective as they block the effects of aldosterone. The efficacy of amiloride and spironolactone were confirmed by non-invasive measurements of cardiac output, vascular resistance, and total body volume.
"This provides alternatives for patients in whom spironolactone is not tolerated. We now have two new treatments based on old drugs. Our study provides strong evidence that either of these two well-established diuretics will achieve excellent blood pressure control in the majority of these patients," explained Dr. Bryan Williams, study investigator, Chair of Medicine at University College London, UK.
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