Can spironolactone lower blood pressure when all other drugs have failed?

This study looked at how effectively spironolactone (Aldactone) lowers blood pressure (BP) in patients with resistant hypertension (RH). They found that spironolactone significantly lowers BP in some patients after three months.

High BP can lead to strokes and heart attacks. There are many types of medication that are used to lower BP. Up to 3 medications are prescribed to some patients. However, some patients continue to have high BP despite using all three of these medications. These patients have what is called resistant hypertension (RH). They need a fourth treatment to lower their BP but research is needed to determine which additional treatment is best

Spironolactone is a diuretic drug ("water pill"). It prevents the body from absorbing too much salt and keeps the potassium levels at a steady level. Some studies suggest spironolactone is effective as a fourth medication in patients with RH. However, it is not clear if spironolactone is the most effective treatment in these patients.

This study analyzed the results of 12 studies involving 1,655 participants. All participants had RH. They were treated with an additional treatment to lower their BP. The treatments used included spironolactone, a surgical procedure called renal nerve denervation, other BP-lowering medications, or a placebo. Participants’ BP was monitored either in their doctor’s office or by 24 hour BP monitoring at home. 

Spironolactone lowered both systolic BP (SBP;  BP when the heart beats) and diastolic BP (DBP; BP between heartbeats) significantly on 24-hour BP monitoring. It lowered SBP by 10.31 mmHg more than placebo on average and by 6.98 mmHg more than other drugs. It also lowered DBP by 3.94 mmHg compared to placebo and by 3.03 mmHg compared to other drugs.

Spironolatone lowered SBP and DBP the same amount as renal nerve denervation surgery. Spironolactone was most effective after three months of use but became less effective if used for a longer time.

This study showed that spironolactone is effective at lowering blood pressure in patients with resistant hypertension.  

This study was based on previous studies and is limited by the data they include.