High blood pressure is one of the most common long-term health problems in the world.
Millions of adults have it, and many do not even know they are affected because it often causes no clear symptoms in the early stages.
This is why high blood pressure is sometimes called a “silent killer.” Over time, the extra pressure inside the blood vessels can damage the heart, brain, kidneys, and other organs.
If it is not treated, it can greatly increase the risk of heart attack, stroke, heart failure, kidney disease, and other serious health problems.
Doctors usually recommend healthy lifestyle changes as the first step to help lower blood pressure.
Eating less salt, choosing a diet rich in fruits and vegetables, exercising regularly, maintaining a healthy weight, avoiding smoking, limiting alcohol, and managing stress can all help. However, many people also need medicine because lifestyle changes alone are not enough to keep their blood pressure under control.
Two of the most commonly prescribed medicines for high blood pressure are chlorthalidone and hydrochlorothiazide. Both belong to a group of medicines called diuretics, often known as “water pills.”
They help the body remove extra salt and water through urine, reducing the amount of fluid in the blood vessels and lowering blood pressure.
For many years, both medicines have been widely used, and some treatment guidelines have favored chlorthalidone because it lasts longer in the body and has been thought to provide stronger protection against heart disease.
Now a very large study suggests that although both medicines lower blood pressure well, one may carry a much higher risk of harmful side effects.
Researchers from Columbia University analyzed the health records of more than 730,000 people over a period of 17 years. This makes it one of the largest studies ever to compare the safety of these two blood pressure medicines in everyday medical practice.
The researchers found that both chlorthalidone and hydrochlorothiazide were similarly effective at lowering blood pressure and reducing the risk of major heart-related problems. However, patients taking chlorthalidone experienced significantly more side effects.
The biggest concern was a condition called hypokalemia, which means the level of potassium in the blood becomes too low. Potassium is an important mineral that helps muscles work properly and allows the heart to beat normally. When potassium levels fall too much, people may develop muscle weakness, tiredness, cramps, irregular heartbeats, confusion, kidney problems, and in some cases a higher risk of developing type 2 diabetes.
The study found that 6.3% of people taking chlorthalidone developed hypokalemia. In comparison, only 1.9% of those taking hydrochlorothiazide experienced the same problem. In other words, the risk was more than three times higher among people using chlorthalidone.
The researchers also found that patients taking chlorthalidone were more likely to develop other electrolyte imbalances and kidney problems, even when they were taking relatively low doses of the medicine. Electrolytes such as potassium and sodium are minerals that help control many important body functions, including nerve signals, muscle movement, and fluid balance. When these minerals become too high or too low, serious health problems can occur.
These findings have raised important questions about whether chlorthalidone should continue to be the preferred first-choice medicine for many patients with high blood pressure.
While the drug remains effective, the higher risk of side effects suggests that doctors may need to monitor patients more closely by checking blood tests regularly.
For some people, hydrochlorothiazide or another blood pressure medicine may be a safer option, depending on their overall health and medical history.
The study also highlights that there is no single medicine that is best for everyone. Factors such as age, kidney function, other medical conditions, and the medicines a person already takes all play a role in choosing the most suitable treatment. This is known as personalized care, where treatment is matched to the needs of each individual instead of using the same approach for every patient.
People who are already taking chlorthalidone should not stop their medicine on their own. Suddenly stopping blood pressure treatment can allow blood pressure to rise again, increasing the risk of heart attack or stroke. Anyone who has concerns should speak with their doctor, who can decide whether blood tests, a dose adjustment, or a different medicine is needed.
Even with effective medicines, healthy habits remain an important part of controlling blood pressure. Regular physical activity, a balanced diet, reducing salt intake, avoiding smoking, limiting alcohol, sleeping well, and managing stress can all improve blood pressure and reduce the risk of heart disease.
Many doctors also encourage patients to check their blood pressure at home so they can track how well their treatment is working.
The study was led by Dr. George Hripcsak of Columbia University and was published in the journal JAMA Internal Medicine. The findings provide valuable new evidence that could help doctors make safer treatment decisions.
Future research will continue to compare blood pressure medicines and look for ways to reduce side effects while keeping blood pressure under good control. The goal is to help patients receive treatment that is both effective and as safe as possible.
If you care about high blood pressure, please read studies about unhealthy habits that may increase high blood pressure risk, and drinking green tea could help lower blood pressure.
For more information about high blood pressure, please see recent studies about what to eat or to avoid for high blood pressure, and 12 foods that lower blood pressure.
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