High blood pressure, also known as hypertension, is one of the most common health problems in Australia. Doctors say more than one in three Australian adults aged 18 and older live with the condition.
Many people do not even know they have high blood pressure because it often causes no clear symptoms at first.
However, over time, it can quietly damage the body and raise the risk of heart disease, stroke, kidney problems, and other serious illnesses. Because of these dangers, millions of people take medicine every day to keep their blood pressure under control.
One of the most widely used medicines for this condition is hydrochlorothiazide. Doctors have prescribed this drug for many years because it is affordable and usually works well.
The medicine helps the body remove extra salt and water, which lowers blood pressure and reduces pressure on the heart. In Australia and many other countries, hydrochlorothiazide has become a very common long-term treatment for older adults.
Now, researchers from UNSW Sydney have discovered a possible health concern linked to this medication. Their study suggests that people taking hydrochlorothiazide may have a higher chance of developing certain kinds of skin cancer, especially older adults who use the drug for a long time.
The researchers explained that hydrochlorothiazide can make the skin more sensitive to sunlight. When skin becomes more sensitive to ultraviolet rays from the sun, it may burn more easily and suffer more damage over time.
Australia already has one of the highest skin cancer rates in the world because of the country’s strong sunlight and high UV levels. This means that even a small increase in sun sensitivity could become important for people who spend time outdoors.
To better understand the possible risk, the research team studied health records from the Department of Veterans’ Affairs in Australia. The information included anonymous records about medicine use, hospital visits, and cancer diagnoses among people aged 65 and older living in New South Wales. The data covered the years from 2004 to 2015.
The researchers compared people who developed skin cancer with people who did not. The study included 45 people with lip cancer and 659 people with melanoma, which is one of the most dangerous forms of skin cancer. These groups were compared with more than 13,000 people who did not develop skin cancer.
After examining the records, the researchers found that people taking hydrochlorothiazide had a higher risk of melanoma and squamous cell lip cancer.
The risk appeared to become stronger the longer people used the medicine. In particular, people who had taken the drug for many years showed a much higher chance of developing lip cancer.
Even though the findings may sound worrying, health experts strongly warn people not to stop taking their blood pressure medicine suddenly. High blood pressure itself is dangerous and can lead to life-threatening health problems if left untreated. Stopping medication without medical advice may increase the risk of heart attacks or strokes.
Instead, doctors say the study should encourage greater awareness and more careful monitoring. Patients using hydrochlorothiazide may benefit from regular skin checks and stronger sun protection habits.
Experts recommend using sunscreen, wearing hats and protective clothing, staying in the shade when possible, and avoiding long periods in the sun during the hottest hours of the day.
The findings have also led to changes in official medicine information. The prescribing information for hydrochlorothiazide has now been updated to include warnings about the possible skin cancer risk. This update is meant to help doctors and patients make informed decisions about treatment and long-term health care.
The UNSW Sydney study is not the first to suggest this connection. Earlier studies from other countries also reported a possible link between hydrochlorothiazide and skin cancer.
The Australian study adds more evidence and highlights the importance of studying the long-term effects of commonly used medicines. Even medicines that have been trusted for decades may still carry risks that become clearer over time.
For many Australians, the research is also an important reminder about sun safety. Australia’s climate and strong sunlight already place people at high risk of skin damage. Taking extra care in the sun may become even more important for people using medicines that increase sensitivity to UV rays.
The research was led by Dr. Benjamin Daniels from UNSW Sydney and was published in the journal Basic & Clinical Pharmacology & Toxicology. The findings provide important information for doctors, patients, and health authorities.
While controlling high blood pressure remains extremely important, the study shows that doctors also need to consider the wider health effects of long-term medicines and help patients protect themselves from possible additional risks.
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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