High blood pressure, also known as hypertension, is a very common health problem, especially among older adults. In Australia, more than one in three adults has high blood pressure.
Many people do not notice any symptoms, but over time it can quietly damage the body. If it is not treated, high blood pressure can lead to serious conditions such as heart attacks, strokes, kidney disease, and problems with eyesight. Because of these risks, doctors often prescribe medicines to help keep blood pressure under control.
One of the most widely used medicines for this purpose is hydrochlorothiazide. This drug has been prescribed for many years and is trusted by doctors because it helps the body remove extra salt and water through urine.
By reducing the amount of fluid in the blood vessels, it lowers the pressure inside them. Many people take this medicine every day for long periods of time, sometimes for the rest of their lives.
However, new research from UNSW Sydney has raised concerns about a possible side effect that may affect older people who use this medication.
The study found a link between hydrochlorothiazide and a higher risk of certain types of skin cancer. This is important because Australia has one of the highest rates of skin cancer in the world due to strong sunlight and outdoor lifestyles.
The researchers discovered that hydrochlorothiazide can make the skin more sensitive to sunlight. This means that people taking the drug may burn more easily when exposed to the sun, even during normal daily activities. Over many years, repeated sun damage can increase the risk of developing skin cancers, including melanoma and cancers of the lip.
To investigate this issue, the research team examined medical records from the Department of Veterans’ Affairs. They focused on people in New South Wales who were 65 years of age or older.
The records included information about hospital visits, cancer diagnoses, and the medicines people had taken. The study covered more than a decade, from 2004 to 2015, and included data from over 13,000 older adults.
When the scientists compared people who developed skin cancer with those who did not, they found that the risk was higher among those who had used hydrochlorothiazide. In particular, people who had taken the drug for a long time were more likely to develop lip cancer. This suggests that the risk may increase with continued use over many years.
Although these findings sound worrying, doctors emphasize that people should not stop taking their medication without medical advice. High blood pressure itself is dangerous, and stopping treatment suddenly could lead to serious health problems. Instead, the goal is to balance the benefits of controlling blood pressure with ways to reduce any added risks.
There are several simple steps that can help lower the risk of skin damage while continuing treatment. Protecting the skin from the sun is especially important.
This includes using sunscreen regularly, wearing wide-brimmed hats and protective clothing, and avoiding outdoor activities during the middle of the day when sunlight is strongest. Regular skin checks can also help detect any early changes before they become serious.
In response to this research, the official information for hydrochlorothiazide in Australia has been updated to include warnings about the possible risk of skin cancer, especially for long-term users. This helps doctors discuss the risks with their patients and decide whether this medicine is still the best option or if another treatment might be more suitable.
The study, led by Dr. Benjamin Daniels and published in the journal Basic & Clinical Pharmacology & Toxicology, adds to growing evidence from other countries that have reported similar findings. It shows that while medicines can save lives and prevent disease, they may also have unexpected side effects that need careful monitoring.
For people living with high blood pressure, the key message is not to panic but to stay informed. Regular check-ups, honest conversations with doctors, and healthy daily habits can help people manage their condition safely. Looking after the whole body—including the heart, skin, and overall well-being—can lead to better health and peace of mind.
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