Prescription drugs come with dozens of side effects. That’s normal. What’s unusual is when researchers discover a new side effect in a drug you’ve been taking regularly. Yet, that’s exactly what happened to a lot of people with high blood pressure.
A new study by researchers from UNSW Sydney found that hydrochlorothiazide, one of the most common drugs used for high blood pressure in Australia, increases the risk of skin and lip cancer. The results were especially worrying for older patients (aged 65 and over).
High blood pressure or hypertension is a condition characterized by having a blood pressure at or above 130/80 mm Hg. Hypertension leads to increased risks of strokes and heart attacks, and it’s been credited as the leading cause of death for around half a million Americans each year.
Higher risks of skin and lip ca-nc-er
The reason for this side-effect turns out to be pretty simple. Hydrochlorothiazide contains photosynthesizing properties that make our skin much more sensitive to the sun. This problem is especially significant for people living in sunny environments. Understandably, this discovery was made by scientists from Sidney.
The study was conducted through a big data analysis of skin cancer rates in a case-control study among older Australians. The results support similar findings from previous international studies (UK, Denmark, and the U.S.) that linked hydrochlorothiazide to an increased risk of skin cancer.
The lead author of the study was Dr. Benjamin Daniels, a pharmacoepidemiologist and a research fellow at the UNSW Medicine’s Centre for Big Data Research in Health (CBDRH).
In the study, the team used data from the Department of Veterans Affairs (DVA). It included de-identified information about cancer registrations, hospitalizations, and medicine dispensing for DVA healthcare cardholders (aged 65 and over) who lived in NSW between 2004 and 2015.
The researchers compared hydrochlorothiazide use in people who had been diagnosed with lip cancer (45 cases) or malignant melanoma (659 cases) compared with those with neither diagnosis (13,300 controls).
“We found an increased risk for developing malignant melanoma and squamous cell cancer of the lip (lip cancer) with hydrochlorothiazide use,” lead author Dr Benjamin Daniels said.
