Spironolactone trimmed post-stroke blood pressure more than usual care
Stroke survivors with uncontrolled hypertension had substantially better blood pressure control when spironolactone was added to their regimen, offering a low-cost option for a problem that often persists long after the acute event. In the REDUCE trial, home systolic blood pressure at three months averaged nearly 8 mm Hg lower with spironolactone than with usual post-stroke care, a difference that is clinically meaningful in secondary stroke prevention. The treatment arm also reached the recommended target of less than 130/80 mm Hg much more often, with 52% hitting goal compared with 30% in the usual-care group.
A reduction of that size matters because recurrent stroke risk tracks closely with uncontrolled blood pressure, whether the original event was ischemic or hemorrhagic. After a stroke, the vasculature remains vulnerable, and persistent hypertension drives additional arterial injury, small-vessel damage, and renewed hemorrhagic or thrombotic risk. By blocking aldosterone, spironolactone reduces sodium and water retention, lowers intravascular volume, and can blunt a hormonal pathway that often keeps blood pressure elevated despite standard therapy. The drug’s long history in hypertension makes the result especially practical: this is not a novel mechanism, but a familiar one being deployed earlier and in a higher-risk population.
One sentence captures the clinical signal: blood pressure moved quickly and decisively.
Earlier use appeared to produce the strongest blood pressure response
Investigators enrolled 160 adults with prior stroke and uncontrolled blood pressure across five U.S. medical centers between April 2021 and October 2025. The cohort had a mean age of 63 years, 38% were women, 29% self-identified as Black adults, and 16% as Hispanic adults. About half had survived a hemorrhagic stroke and the remainder an ischemic stroke, so the trial did not focus on a single cerebrovascular mechanism. Baseline home systolic blood pressure averaged 136 mm Hg, placing the group above the recommended range despite ongoing post-stroke care.
Participants first measured blood pressure at home for three to five days, then were randomized to daily spironolactone in addition to usual medications or to standard post-stroke care without spironolactone. Both participants and researchers knew the assigned treatment, which increases the possibility of bias in a trial centered on blood pressure, though the outcome itself was measured at home with a digital monitor. Blood pressure was reassessed at one, two, three, and six months. At three months, home systolic pressure in the spironolactone arm averaged about 126 mm Hg versus 133 mm Hg in the usual-care arm. Diastolic pressure also fell more, by about 4 mm Hg on average.
The exploratory timing signal will draw attention in clinics. People who began spironolactone within three months of their stroke seemed to have a larger blood pressure drop than those who started later. That pattern fits the biology: early after stroke, blood pressure often remains labile, neurohormonal activation can persist, and clinicians may still be intensifying therapy. Introducing aldosterone blockade during that window may interrupt a mechanism that continues to sustain hypertension even after the acute neurologic insult has passed.
Safety looked acceptable, but potassium monitoring remains essential
The trial did not show a major safety penalty. Serious side effects requiring hospitalization occurred at similar rates in both groups, 15% with spironolactone and 16% with standard post-stroke medications. Hyperkalemia occurred in about 4% of patients receiving spironolactone, and no life-threatening complications were reported. For a medication that raises potassium by design, that finding is reassuring but not trivial. In everyday practice, spironolactone demands laboratory surveillance, especially in patients with kidney disease, diabetes, or other reasons to retain potassium.
The blood pressure effect also came with a small imbalance in background treatment intensity. By three months, participants in the spironolactone group were taking an average of 2.6 blood pressure medications compared with 2.1 in the usual-care group. That difference leaves open the possibility that some of the observed benefit came from overall regimen intensification rather than spironolactone alone. Even so, the degree of separation in home blood pressure, along with the higher rate of goal attainment, supports a real pharmacologic contribution from the mineralocorticoid receptor blocker itself.
The trial was also stopped early, closing enrollment at 160 participants instead of the planned 200, and about 15% of participants lacked three-month blood pressure readings. Those gaps limit precision and reduce confidence in the exact size of the treatment effect. The study was not designed to answer the larger question patients and clinicians care about most: whether spironolactone actually prevents another stroke or myocardial infarction. Larger and longer studies will be needed to determine whether the observed blood pressure improvement translates into fewer hard cardiovascular events.
Even with those limitations, the practical message is hard to ignore. Secondary stroke prevention still depends heavily on blood pressure control, and many survivors remain above target despite multiple medications. A widely available diuretic that is inexpensive, familiar to clinicians, and capable of producing an additional drop in home systolic blood pressure has immediate appeal, especially when the goal is to lower risk rather than wait for another cerebrovascular event to prove the point. The REDUCE findings suggest that earlier aldosterone blockade may deserve a closer look in post-stroke care, but the definitive test will be whether the blood pressure gains hold up in a larger trial powered for recurrent stroke and cardiovascular outcomes.