A low-cost drug may help stroke survivors whose blood pressure stays high despite treatment, according to a new study.
The REDUCE trial examined whether adding spironolactone, sometimes called a water pill, to regular care could lower blood pressure after a stroke. Researchers presented the findings at the American Heart Association’s Scientific Sessions in Chicago, held Nov. 6-9, 2026.
Participants either added spironolactone to their existing treatment or continued with their usual post-stroke care. Researchers followed their blood pressure readings at home for six months.
At the three-month mark, the average top blood pressure number was about 126 among those taking spironolactone, compared with 133 in the usual-care group. More people taking the medication also reached the recommended target of below 130/80: 52%, versus 30% of those receiving usual care.
“Lowering blood pressure is the most important step in preventing another stroke, yet many survivors struggle to reach recommended blood pressure targets after a stroke,” said study co-lead author Dr. Jordana Cohen, an associate professor of medicine and epidemiology at the University of Pennsylvania.
Cohen said the reduction seen with spironolactone could potentially lower the risk of future strokes and heart attacks. But the study did not test whether the medication actually prevented those events.
Dr. Alfred Joshua, an emergency physician in California who was not involved in the research, called the results encouraging while noting that an effect on repeat strokes remains uncertain. The trial measured blood pressure, he said, so it cannot establish whether adding the drug leads to fewer strokes.
Spironolactone helps the body remove extra salt and water, which can lower blood pressure. It can also cause potassium to build up, so people taking it need to have their potassium levels monitored.
Joshua said high potassium can develop without noticeable symptoms, with greater risks for people who have kidney problems or take certain medications or potassium supplements. The drug may also lower blood pressure enough to cause dizziness.
For people whose blood pressure remains high after a stroke, Joshua suggested bringing home readings to a clinician and asking whether spironolactone might be appropriate.
The trial ended early, enrolling 160 people rather than the planned 200. About 15% of participants did not have blood pressure readings available at the three-month point. Those assigned spironolactone were also taking slightly more blood pressure medications overall than those receiving usual care.
Researchers said larger, longer studies are needed to determine whether spironolactone can prevent another stroke or a heart attack.
