High blood pressure, also known as hypertension, is one of the most common long-term health conditions. In Australia, more than one in three adults aged 18 and older have high blood pressure.
If it is not treated, it can damage blood vessels over time and greatly increase the risk of heart attack, stroke, kidney disease, and other serious health problems. Because of these risks, many people need medicine to keep their blood pressure under control.
One of the medicines that has been widely used for many years is hydrochlorothiazide. Doctors often prescribe it because it helps the body remove extra salt and water, lowering blood pressure and reducing strain on the heart.
It has helped many people lower their risk of heart disease, but new research suggests that long-term use may also have an important side effect that patients and doctors should understand.
A team of researchers from UNSW Sydney examined whether hydrochlorothiazide might increase the risk of certain types of skin cancer. Their findings were published in the journal Basic & Clinical Pharmacology & Toxicology. The study adds to growing international evidence that this commonly used medicine may make the skin more vulnerable to damage from sunlight.
The researchers studied health records from the Australian Department of Veterans’ Affairs. They focused on people aged 65 years and older living in New South Wales between 2004 and 2015. The records included prescription medicines, hospital visits, and cancer diagnoses, allowing the scientists to compare more than 13,000 older adults.
The team compared people who developed skin cancer with similar people who did not. Among the cancer cases were 45 people with lip cancer and 659 people with malignant melanoma, the most dangerous form of skin cancer. After analysing the information, the researchers found that people who had taken hydrochlorothiazide were more likely to develop both melanoma and lip cancer.
They also found that the risk of lip cancer became higher the longer the medicine was used. One possible reason is that hydrochlorothiazide can make the skin more sensitive to ultraviolet rays from the sun. Over many years, this extra sensitivity may increase damage to skin cells, raising the chance that cancer could develop.
Even though these results are important, the researchers strongly advise people not to stop taking hydrochlorothiazide on their own. High blood pressure is a serious condition that needs proper treatment, and suddenly stopping medicine can increase the risk of dangerous health problems. Anyone with concerns should discuss them with their doctor before making any changes.
There are also practical ways to lower the possible risk while continuing treatment. Wearing sunscreen, using protective clothing and wide-brimmed hats, seeking shade, and avoiding strong sunlight during the middle of the day can help protect the skin. Regular skin checks may also help find suspicious spots early, when treatment is usually much more successful.
The findings have already influenced medical practice in Australia. The official prescribing information for hydrochlorothiazide now includes warnings about the possible increased risk of skin cancer, particularly after long-term use. This helps doctors provide better advice so patients can balance the benefits of controlling blood pressure with the need to protect their skin.
Lead author Dr. Benjamin Daniels said the research should help patients and healthcare professionals make better-informed decisions together. The study reminds us that medicines can offer major health benefits while also having side effects that require careful monitoring.
By staying informed, protecting the skin from the sun, and having regular discussions with healthcare providers, people can continue managing high blood pressure safely while reducing potential long-term risks.
If you care about skin health, please read studies about eating fish linked to higher risk of skin cancer, and Vitamin B3 could help prevent skin cancers.
For more health information, please see recent studies about vegetable oil linked to spread of cancer, and results showing Vitamin D could help treat skin inflammation.
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