High blood pressure, also called hypertension, is a common condition that affects more than one in three Australian adults aged 18 and older.
If not treated properly, it can lead to serious health problems like heart disease and stroke.
To manage high blood pressure, doctors often prescribe medicines such as hydrochlorothiazide.
This drug is widely used in Australia. But a new study from UNSW Sydney has found a possible risk linked to this medication: a higher chance of developing skin cancer, especially in older adults.
Hydrochlorothiazide can make your skin more sensitive to sunlight. This means people taking the drug might be more likely to get sunburned or develop sun-related skin damage.
The study looked at data from the Department of Veterans’ Affairs (DVA). It included anonymous information about cancer diagnoses, hospital visits, and medication use among Australians aged 65 and older in New South Wales. The data covered the years from 2004 to 2015.
Researchers compared the use of hydrochlorothiazide among people who developed skin cancers—45 had lip cancer and 659 had melanoma—with more than 13,000 people who did not have skin cancer.
They found that people taking hydrochlorothiazide had a higher risk of getting melanoma and squamous cell lip cancer.
The risk of lip cancer was even greater for people who had been on the medication for a long time. In other words, the longer someone took hydrochlorothiazide, the higher their chance of developing lip cancer.
Even with these findings, experts say that people should not stop taking hydrochlorothiazide suddenly. High blood pressure is a serious condition, and stopping medication without a doctor’s advice can be dangerous.
Instead, the study suggests that doctors should be aware of the skin cancer risk and take extra care with their patients. This could mean checking their skin more often and encouraging sun safety—like using sunscreen, wearing hats and long sleeves, and staying out of the sun during the hottest parts of the day.
To help raise awareness, the official prescribing information for hydrochlorothiazide has been updated to include this new risk. This change aims to help doctors and patients make better decisions about treatment.
The findings match earlier studies from other countries that also found a link between hydrochlorothiazide and skin cancer. It shows the importance of looking at the long-term effects of medications, even ones that are commonly used.
For patients, this study is a reminder to practice sun safety—especially if you are taking medications that make your skin more sensitive to UV rays.
This research was led by Dr. Benjamin Daniels and published in the journal Basic & Clinical Pharmacology & Toxicology. It gives doctors and patients important new information about how blood pressure drugs might affect overall health.
While treating high blood pressure is still very important, this study highlights the need to think about the whole picture, including other health risks that may come with long-term medicine use.
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