A major study from Columbia University has revealed important new information about two widely used medications for high blood pressure: chlorthalidone and hydrochlorothiazide.
Both are commonly prescribed to help prevent serious problems like heart attacks, strokes, and heart failure. While both drugs work well to control high blood pressure, the study found key differences in their safety.
This research is one of the largest of its kind. It followed more than 730,000 patients over 17 years—a massive effort to better understand the real-world effects of these medications. The results show that chlorthalidone, although effective, comes with a higher risk of certain serious side effects compared to hydrochlorothiazide.
One of the most concerning findings was that people taking chlorthalidone were almost three times more likely to develop low potassium levels—a condition called hypokalemia. Potassium is an important mineral that helps keep your heart, muscles, and nerves working properly.
When potassium levels drop too low, it can lead to irregular heartbeats, confusion, muscle weakness, and even kidney damage or type 2 diabetes in some cases.
In this study, 6.3% of people taking chlorthalidone developed low potassium, compared to just 1.9% of those taking hydrochlorothiazide. The risk was higher even when chlorthalidone was given in smaller doses. The study also found that chlorthalidone users were more likely to have electrolyte imbalances and kidney problems, which are also serious health concerns.
These results have led experts to question whether chlorthalidone should still be recommended as often in treatment guidelines. The findings suggest that if a doctor does prescribe chlorthalidone, they should closely monitor the patient’s potassium levels and kidney function, and be prepared to make changes if problems develop.
High blood pressure affects millions of people around the world, and it’s a leading cause of heart disease and stroke. Controlling blood pressure is critical, and often includes a mix of medication, diet, exercise, stress management, and regular medical checkups.
Even though medications are a powerful tool in controlling blood pressure, they are not one-size-fits-all. This study highlights the need for personalized treatment plans, where doctors consider both the benefits and the possible side effects of each medication before choosing the right one for a patient.
It also reminds us that managing blood pressure isn’t just about taking a pill. Healthy lifestyle habits—like eating less salt, being physically active, not smoking, and managing stress—are just as important. Keeping track of your blood pressure at home and staying in touch with your healthcare provider can make a big difference too.
This study, led by Dr. George Hripcsak and published in JAMA Internal Medicine, is a major step forward in helping doctors and patients make more informed choices. It shows how long-term research can uncover hidden risks and help improve treatment strategies for such a widespread condition.
In summary, while both chlorthalidone and hydrochlorothiazide can help manage high blood pressure, hydrochlorothiazide may carry fewer risks for many patients. The study encourages careful decision-making, better monitoring, and a more personalized approach to keeping blood pressure under control and protecting long-term health.
If you care about high blood pressure, please read studies that drinking tea could help lower blood pressure, and early time-restricted eating could help improve blood pressure.
For more health information, please see recent studies about added sugar in your diet linked to higher blood pressure, and results showing vitamin D could improve blood pressure in people with diabetes.
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