Response to Spironolactone in Resistant Hypertension
We thank Drs Feely and Mahmud1 for their comments regarding our published experience of using spironolactone in patients with resistant hypertension in the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT).
We are aware that, unlike the 2004 British Hypertension Society guidelines,2 the updated National Institute of Clinical Excellence (NICE)/British Hypertension Society guidelines no longer recommend spironolactone by name at step 4.3 This may be, in part, because hypertension is no longer a licensed indication for spironolactone use and, in part, because of uncertainty as to whether other diuretics (eg, amiloride) may also be effective in this situation.
In response to the specific points raised by Feely and Mahmud, the reason why twice as many of those randomized to the atenolol-based antihypertensive regimen received spironolactone was that, as reported in the main ASCOT results article,4 this regimen was less effective at lowering blood pressure than the amlodipine-based regimen and fewer participants randomized to atenolol-based therapy therefore achieved target blood pressure on 3 drugs.
Perhaps surprisingly, despite the fact that hypertension is not a licensed indication for spironolactone in the UK, the use of spironolactone was proportionally similar in the Anglo and Scandinavian populations in ASCOT: spironolactone was prescribed in 9% of ASCOT recruits in the UK/Ireland and 10% of those recruited in Scandinavia.
Randomized trials are required to validate current recommendations for drug sequencing because no data are currently available to inform the selection of 3rd and 4th line agents. In the meantime, we agree with Feely and Mahmud that spironolactone should be restored as a useful and preferred drug in this situation.
Feely J, Mahmud A. Spironolactone in resistant hypertension. Hypertension. 2007; 50: e57.
National Collaborating Centre for Chronic Conditions. Hypertension: Management of Hypertension in Adults in Primary Care: Partial Update. London: Royal College of Physicians, 2006.
Dahlof B, Sever PS, Poulter NR, Wedel H, Beevers DG, Caulfield M, Collins R, Kjeldsen SE, Kristinsson A, McInnes GT, Mehlsen J, Nieminen M, O’Brien E, Ostergren J, for the ASCOT Investigators. Prevention of cardiovascular events with an antihypertensive regimen of amlodipine adding perindopril as required versus atenolol adding bendroflumethiazide as required, in the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA): a multicentre randomised controlled trial. Lancet. 2005; 366: 895–906.