A medicine that has been used for many years to treat high blood pressure may have more side effects than doctors once believed.
A large study led by researchers at Columbia University suggests that chlorthalidone, a commonly prescribed blood pressure medicine, may increase the risk of low potassium levels, kidney problems, and other changes in the body’s chemical balance. The findings may help doctors choose the safest treatment for people living with high blood pressure.
High blood pressure, also called hypertension, affects hundreds of millions of people around the world. It develops when blood pushes too strongly against the walls of the arteries over a long period of time.
Most people do not notice any symptoms, but the condition slowly damages blood vessels and important organs. If left untreated, it can increase the risk of heart attack, stroke, heart failure, kidney disease, and vision problems. Because of these dangers, controlling blood pressure is one of the most important ways to protect long-term health.
Doctors often recommend healthy lifestyle changes such as eating more fruits and vegetables, reducing salt, exercising regularly, maintaining a healthy weight, avoiding smoking, and limiting alcohol. However, many people also need medicine to keep their blood pressure under control.
Chlorthalidone belongs to a group of medicines called thiazide diuretics, sometimes known as ‘water pills.’ They help the kidneys remove extra salt and water from the body, reducing the amount of fluid flowing through the blood vessels and lowering blood pressure.
Another commonly prescribed medicine in the same group is hydrochlorothiazide. For many years, some doctors believed chlorthalidone might work better because it stays in the body longer and may lower blood pressure more effectively.
To find out whether one medicine was safer than the other, the Columbia University research team analyzed medical records from more than 730,000 people who had taken these medicines over a period of 17 years. This large amount of health information allowed the researchers to compare the benefits and side effects of the two drugs in everyday medical practice.
The results showed that both medicines helped lower blood pressure and protect against serious heart problems.
However, people taking chlorthalidone were much more likely to develop low potassium, also called hypokalemia. About 6.3 percent of people taking chlorthalidone experienced this problem, compared with only 1.9 percent of those taking hydrochlorothiazide.
Potassium is an important mineral that helps muscles contract, nerves send signals, and the heart beat normally. When potassium levels become too low, people may feel weak, tired, develop muscle cramps, or experience abnormal heart rhythms. In severe cases, low potassium can become life-threatening if it is not treated.
The researchers also found that people taking chlorthalidone had a greater risk of changes in electrolytes, which are minerals that help control fluid balance, muscle function, and many other body processes.
They also had a higher chance of developing kidney problems. These findings do not mean everyone who takes chlorthalidone will develop complications, but they do suggest that doctors may need to monitor patients more closely with blood tests and regular check-ups.
It is important for patients not to stop taking their blood pressure medicine without speaking to their doctor. High blood pressure itself is a serious condition, and stopping treatment suddenly may increase the risk of heart attack or stroke. If someone is concerned about possible side effects, their doctor can discuss whether another medicine may be more suitable.
The study also highlights the importance of combining medicine with healthy daily habits. Eating a balanced diet, reducing salt intake, staying physically active, maintaining a healthy weight, getting enough sleep, managing stress, and avoiding tobacco all help lower blood pressure and improve heart health.
Although more research is needed, this large study provides valuable information that may help doctors choose the safest treatment for each patient. Careful monitoring and regular medical reviews can help people receive the benefits of blood pressure treatment while reducing the risk of unwanted side effects.
This research was led by Columbia University researchers and was based on a large observational study comparing chlorthalidone and hydrochlorothiazide.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
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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