Researchers from Columbia University have discovered that chlorthalidone, a commonly prescribed diuretic for lowering blood pressure, may cause more serious side effects than hydrochlorothiazide, another medication that is often used for the same purpose.
This finding goes against current medical guidelines, which recommend chlorthalidone over hydrochlorothiazide for treating high blood pressure.
The study analyzed 17 years of medical data from more than 730,000 patients who were being treated for high blood pressure. Both chlorthalidone and hydrochlorothiazide were found to be equally effective at preventing major health problems like heart attacks, heart failure hospitalizations, and strokes.
However, the researchers noticed a concerning difference in the side effects experienced by patients taking chlorthalidone.
Patients who were treated with chlorthalidone had nearly three times the risk of developing dangerously low levels of potassium in their blood compared to those taking hydrochlorothiazide. This condition, known as hypokalemia, can be very dangerous because potassium is crucial for heart and muscle function.
Low potassium levels can lead to abnormal heart rhythms, muscle weakness, and even paralysis in severe cases. The study found that 6.3% of people taking chlorthalidone developed hypokalemia, compared to only 1.9% of those on hydrochlorothiazide.
Surprisingly, even when patients were given lower doses of chlorthalidone, their risk of low potassium levels was still higher than for those taking hydrochlorothiazide.
In addition to low potassium levels, patients taking chlorthalidone were also at greater risk for other types of electrolyte imbalances, such as low sodium levels, a condition known as hyponatremia.
Hyponatremia can cause symptoms like confusion, headaches, seizures, and in severe cases, it can lead to coma. The researchers also found a greater risk of kidney problems among patients taking chlorthalidone.
The researchers stressed that doctors who prescribe chlorthalidone should be aware of these potential side effects and monitor their patients closely. Regular blood tests to check electrolyte levels and kidney function might be necessary to prevent serious complications.
This is particularly important because electrolyte imbalances and kidney issues can sometimes develop without obvious symptoms until they become serious.
This study is not the first to raise concerns about the safety of chlorthalidone. A previous observational study also found that chlorthalidone was linked to more electrolyte imbalances compared to hydrochlorothiazide.
However, because chlorthalidone has been recommended for its effectiveness in lowering blood pressure and preventing heart-related issues, many doctors continue to prescribe it as the first choice.
The findings from this research suggest that the current medical guidelines may need to be revisited. If hydrochlorothiazide is just as effective at preventing heart attacks and strokes but comes with fewer risks of severe side effects, it may be a safer choice for many patients.
For people currently taking chlorthalidone, it may be worth discussing with their doctor whether switching to hydrochlorothiazide or another blood pressure medication is a better option, especially if they are experiencing side effects.
The study was led by George Hripcsak and was published in JAMA Internal Medicine. The research team hopes their findings will encourage doctors to carefully consider the risks and benefits of these medications and to monitor patients closely for any signs of side effects.
This study also highlights the importance of personalized medicine, where treatment decisions are made based on an individual’s health risks and response to medications. For many people with high blood pressure, choosing the right medication can make a big difference in both safety and long-term health.
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.
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