A systematic review of 12 trials1 found that spironolactone reduced the office systolic blood pressure by an average of 20.12 mm Hg 5.73 mm Hg diastolic. On the 24-hour assessment, there was a reduction of 10.31 mm Hg.
Treatment-resistant hypertension was described as “the inability to reach standard BP levels (below 140/90 mm Hg) despite the concurrent use of 3 or more antihypertensive agents of different classes that include at least one kind of diuretic is defined as resistant hypertension”.
Spironolactone is very effective but a difficult medication to use. It can cause GI disturbances, as well as breast pain and enlargement in men. There is a safety issue and monitoring of serum potassium needs to be done within days of starting and regularly thereafter. In Europe, it is a 4th line drug but in New Zealand, a 5th line after betablockers.
