A new drug may help people with high blood pressure that does not respond to existing medications.
The results of a large clinical trial, published August 30 in the New England Journal of Medicine, suggest that baxdrostat could offer an alternative for people with resistant hypertension — high blood pressure that stays elevated despite standard therapy. Baxdrostat is one of a new class of drugs called aldosterone synthase inhibitors.
High blood pressure affects 1.3 billion people worldwide, yet 80 percent don’t get adequate treatment. Uncontrolled blood pressure increases the risk of stroke, heart attack and heart failure. Blood pressure itself is the force of blood pushing through your arteries. Doctors record it as two numbers: systolic (the first number) and diastolic (the second number), in millimeters of mercury, or mm Hg.
A healthy blood pressure is usually below 120/80 mm Hg, while 130/80 mm Hg or above is considered high, often caused by excess aldosterone, a hormone that maintains salt and water balance. Baxdrostat works by lowering aldosterone, preventing fluid buildup.
The 12-week Phase III trial enrolled nearly 800 patients with resistant or uncontrolled high blood pressure, with an average pressure of 149/87 mm Hg. Compared with participants given a placebo, those taking 1 or 2 milligrams of baxdrostat alongside their current medications saw an average drop of about 9–10 mm Hg more in seated systolic pressure — basically, the reading you’d get when sitting for a few minutes at a doctor’s appointment. A small number of patients in a substudy also saw a drop of about 15 mm Hg in systolic pressure averaged over 24 hours, with no major side effects.
“Existing blood pressure drugs like spironolactone can cause side effects such as breast tenderness and reduced sexual function in men, or menstrual irregularities in women,” says John Flack, an internal medicine specialist at Southern Illinois University in Springfield. “What’s exciting about baxdrostat is that it avoids these problems while still effectively lowering blood pressure.”
About 40 percent of patients on the drug reached healthy systolic levels below 130 mm Hg, compared with 19 percent on placebo. And this was consistent across men and women of different ages as well as patients taking either two blood pressure medications or three or more, Flack says, “which shows the drug works well in a broad range of people.” The team also presented their findings August 30 at the European Society of Cardiology Congress 2025 in Madrid.
Yale University cardiologist Erica Spatz, who was not involved in the study, says the results are “impressive and meaningful,” particularly for patients struggling to control their blood pressure.
Baxdrostat was generally well tolerated. “As expected, we saw mild increases in potassium, but far less than with spironolactone,” Flack says. Kidney effects were minor and may even be beneficial, he says, because they may reduce harmful hyperfiltration — when the kidneys overwork, filtering more blood than normal.
The trial also included an eight-week withdrawal phase. Patients who stopped baxdrostat saw a 1.4 mm Hg rise in systolic pressure on average, while those who continued treatment had an additional 3.7 mm Hg drop. “Even at week 12, blood pressure in the baxdrostat group was still coming down,” Flack says. “That kind of prolonged response is unlike any other blood pressure drug class we use.”
Spatz agrees. “Adherence to blood pressure medications is often poor, so this kind of sustained effect is amazing.”
Both experts believe that the observed reductions could reduce the long-term risk of heart attack, stroke and heart failure. Spatz points out that the latest American Heart Association blood pressure guidelines put a strong emphasis on assessing overall cardiovascular risk and starting medications when needed. A key tool in this process is PREVENT, a calculator that estimates a person’s 10- and 30-year risk of heart disease based on blood pressure, cholesterol, age and other health factors.
“For individuals at high cardiovascular risk as estimated using the PREVENT calculator, achieving a systolic pressure below 120 mm Hg is even more protective than targeting below 130 mm Hg,” she says. Spatz notes that for patients who need powerful medications to reach those targets, baxdrostat could be an important tool.
Though the drug’s developer, AstraZeneca, which also funded the study, plans to seek U.S. regulatory approval by late 2025, Spatz cautions that more research is needed to see if baxdrostat could be used as a first- or second-line therapy and provide the same heart protection as current drugs. And “even if approved, it must be combined with lifestyle changes, regular monitoring and comprehensive care to fully reduce cardiovascular risk.”
