Millions of people around the world live with high blood pressure, also called hypertension.
This condition happens when blood pushes too hard against the walls of the blood vessels over a long period of time.
Many people do not notice any symptoms, which is why high blood pressure is often called a silent health problem. If it is not treated, it can slowly damage the heart, brain, kidneys, and blood vessels.
Over time, it can increase the risk of heart attacks, strokes, heart failure, and kidney disease. Because of these dangers, doctors often recommend healthy lifestyle changes and, when needed, medicines to help lower blood pressure.
One group of medicines commonly used to treat high blood pressure is called diuretics, sometimes known as “water pills.” These medicines help the body remove extra salt and water through urine, making it easier for the heart to pump blood. Two of the best-known medicines in this group are chlorthalidone and hydrochlorothiazide.
For many years, some doctors believed chlorthalidone was the better choice because earlier research suggested it could control blood pressure very well and might offer stronger protection against heart disease.
However, a new study from Columbia University suggests that the medicine may also carry more risks than many people realized. The researchers wanted to better understand how safe these two medicines are when used by large numbers of patients in everyday medical care rather than only in clinical trials.
The research examined health records from more than 730,000 people who took blood pressure medicines over a period of 17 years.
By comparing patients who used chlorthalidone with those who took hydrochlorothiazide, the scientists were able to look for important differences in side effects while both medicines were being used to lower blood pressure and reduce the risk of heart attacks and strokes.
The results showed that people taking chlorthalidone were much more likely to develop low potassium levels, a condition known as hypokalemia. About 6.3% of people taking chlorthalidone developed this problem, compared with only 1.9% of those taking hydrochlorothiazide.
Potassium is an important mineral that helps muscles move, nerves send signals, and the heart beat in a normal rhythm. When potassium levels become too low, people may feel weak, tired, or have muscle cramps. In serious cases, dangerous changes in heart rhythm can occur.
The researchers also found that chlorthalidone users had a greater chance of developing kidney problems and changes in other electrolytes. Electrolytes are minerals in the blood, such as sodium and potassium, that help control fluid balance, muscle movement, and nerve function. If these minerals become too high or too low, the body may not work properly.
The findings do not mean that chlorthalidone is unsafe for everyone or that patients should stop taking it. Many people have taken the medicine safely for years and continue to benefit from good blood pressure control.
Instead, the study suggests that doctors may need to monitor patients more carefully. Blood tests can help check potassium levels and kidney function, especially after starting treatment or changing the dose.
The study may also encourage doctors to think more carefully about which medicine is the best choice for each patient. Someone who already has kidney disease or low potassium levels may benefit from a different treatment. Medical decisions should always be based on a person’s overall health, medical history, and advice from their healthcare provider.
Medicine is only one part of controlling high blood pressure. Healthy habits also play an important role. Eating more fruits, vegetables, whole grains, beans, and lean proteins can support heart health. Reducing salt intake may help lower blood pressure for many people.
Regular physical activity, such as walking for about 30 minutes most days of the week, can also make a difference. Avoiding smoking, limiting alcohol, maintaining a healthy weight, getting enough sleep, and managing stress can all help keep blood pressure under better control.
The researchers hope their findings will help doctors choose treatments more safely and improve patient care. More studies are expected to explore why these differences between the two medicines exist and whether some groups of patients are at greater risk than others. The research was published in the journal JAMA Internal Medicine.
If you take chlorthalidone, do not stop taking it on your own. Instead, speak with your doctor if you have concerns or notice possible side effects. Regular medical check-ups remain one of the best ways to make sure your treatment is working safely and effectively.
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 information about blood pressure, please see recent studies about How to eat your way to healthy blood pressure and results showing that Modified traditional Chinese cuisine can lower blood pressure.
