A large study that followed more than 730,000 people over 17 years has raised new questions about the safety of two of the world’s most commonly prescribed blood pressure medicines.
The research suggests that while both drugs lower blood pressure effectively, one may carry a much greater risk of harmful side effects than the other.
The study was led by researchers at Columbia University and published in JAMA Internal Medicine.
The scientists compared two widely used diuretics, chlorthalidone and hydrochlorothiazide, which are often prescribed to reduce the risk of heart attacks, strokes, and heart failure by lowering blood pressure.
High blood pressure, also called hypertension, affects millions of people around the world. Many people do not know they have it because it usually causes no symptoms.
If it is left untreated, it can damage blood vessels over many years and increase the risk of stroke, heart disease, kidney failure, and other serious health problems.
Both medicines examined in the study are effective at lowering blood pressure. However, when the researchers compared the health records of hundreds of thousands of patients, they found important differences in their safety.
Chlorthalidone was linked to a much higher rate of certain side effects than hydrochlorothiazide.
The biggest concern involved low potassium levels, a condition called hypokalemia. Potassium is a mineral that helps the heart, muscles, and nerves work properly. If potassium levels fall too low, people can develop muscle weakness, tiredness, confusion, abnormal heart rhythms, kidney problems, and a higher risk of developing type 2 diabetes.
In the study, 6.3% of people taking chlorthalidone developed low potassium levels, compared with only 1.9% of those taking hydrochlorothiazide. This means the risk was almost three times higher among people using chlorthalidone.
The researchers also found that chlorthalidone was more likely to cause other electrolyte imbalances and problems affecting kidney function. These risks remained even when patients were given lower doses of the medicine, suggesting that reducing the dose alone may not completely remove the problem.
The findings are encouraging doctors to think carefully about which medicine is the best choice for each patient. For some people, hydrochlorothiazide may offer similar blood pressure control with fewer side effects. Patients who do take chlorthalidone may need regular blood tests so doctors can monitor potassium levels and kidney function.
Medicines are only one part of managing high blood pressure. Doctors also recommend eating a healthy diet, reducing salt intake, exercising regularly, maintaining a healthy weight, limiting alcohol, avoiding smoking, managing stress, and checking blood pressure regularly. These healthy habits can improve blood pressure and reduce the risk of future heart disease.
The researchers say the results highlight the importance of choosing treatments based on each person’s health rather than assuming all medicines in the same group are equally safe.
The study provides valuable information that can help doctors and patients discuss the benefits and risks of treatment and make better decisions about controlling high blood pressure.
If you care about blood pressure, please read studies about how diets could help lower high blood pressure, and 3 grams of omega-3s a day keep high blood pressure at bay.
For more health information, please see recent studies that beetroot juice could help reduce blood pressure, and results showing cinnamon could help lower high blood pressure.
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