High blood pressure is a condition that many people live with every day. It happens when the blood pushes too hard against the walls of the arteries, which can damage them over time.
Think of it like traffic on a busy road—if the cars are going too fast and too close together, there’s a higher chance of an accident. In the same way, high blood pressure can lead to serious problems like heart attacks, strokes, and kidney disease.
To help manage this condition, doctors often prescribe medications. One of those medications is a pill called chlorthalidone. It’s a type of water pill, also known as a diuretic, that helps the body get rid of extra salt and water, which can lower blood pressure. For a long time, many doctors believed that chlorthalidone was better than a similar pill called hydrochlorothiazide.
But a large new study by researchers at Columbia University suggests that chlorthalidone might come with more risks than previously thought.
The researchers looked at the medical records of more than 730,000 people who were treated for high blood pressure over a period of 17 years. They wanted to compare the safety and effectiveness of chlorthalidone and hydrochlorothiazide.
The good news is that both medicines worked well in preventing major heart problems like heart attacks and strokes. But the researchers also found something concerning. People who took chlorthalidone were about three times more likely to have very low levels of potassium in their blood. This condition is called hypokalemia.
Potassium is an important mineral that helps our muscles and nerves work properly. It also helps keep the heartbeat steady. If the potassium level drops too low, a person may feel weak, tired, or dizzy, and it can even cause problems with the heart.
In the study, 6.3% of people who took chlorthalidone developed low potassium levels, compared to only 1.9% of those who took hydrochlorothiazide.
That’s not the only issue. The study also found that people on chlorthalidone had a higher risk of problems with their electrolytes—important chemicals in the body that help with things like muscle function and heart rhythm. On top of that, they were more likely to develop kidney problems, which is especially serious since the kidneys help clean waste from our blood.
This doesn’t mean that chlorthalidone is a bad medicine or that everyone who takes it will have problems. But it does mean doctors might want to think twice before choosing it over hydrochlorothiazide. It’s also a reminder that no medicine is perfect, and what works well for one person may not be the best choice for someone else.
If you or someone you know takes chlorthalidone, there’s no need to panic. But it’s a good idea to have regular check-ups with a doctor and to tell them if you’re feeling more tired than usual or notice anything unusual in your body. Your doctor might want to check your potassium levels or look more closely at how your kidneys are working.
There are also many things people can do on their own to help keep their blood pressure healthy. Eating lots of fruits and vegetables, staying away from salty foods, getting regular exercise, avoiding smoking, and limiting alcohol can all make a big difference.
Managing stress—by doing things like going for walks, listening to music, or practicing deep breathing—can help too.
The researchers plan to keep studying these medications to learn more. Their goal is to make sure everyone gets the safest and most effective treatment possible. In the meantime, staying informed, talking with your doctor, and making healthy choices are the best ways to keep your blood pressure—and your body—in good shape.
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 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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