- Researchers say people over age 66 have a higher chance of skin cancer if they're taking a certain type of blood pressure medication.
- They say thiazide diuretic blood pressure drugs can affect how your skin reacts to sunlight.
- They note there's an easy solution: Just switch blood pressure medications.
If you’re over 66 years old and have a higher risk for skin cancer, you might want to double-check your blood pressure medication.
That’s the recommendation from researchers at the University of Toronto published in the Canadian Medical Association Journal.
The researchers said that people over age 66 who have been taking any thiazide diuretic blood pressure medications for an extended time, and who also have underlying skin cancer risk factors (such as fair and easily burnable skin), have a markedly higher risk of developing skin cancer.
Hydrochlorothiazide, one of the most prescribed thiazide diuretic drugs, seems to be the most “phototoxic,” said Dr. Aaron Drucker, a member of the study team as well as a dermatologist and clinical investigator in the department of dermatology at Brown University’s Alpert Medical School in Rhode Island.
Phototoxic means a drug basically interacts with light to cause a stronger reaction to the sun than usual.
But the news isn’t all bad.
“We did not find that to be the case with other (non-thiazide diuretic blood pressure treatment medications),” Drucker told Healthline. “So that’s good news.”
He added that the plan of action for a person with higher risk would be to simply switch to another medication.
The notion of hydrochlorothiazide increasing the possibility of skin cancer in some people isn't new, Drucker said.
The Food and Drug Administration (FDA) issued a warning in August 2020 about prolonged use of the drug creating a small increased risk of skin cancer.
The European Medicines Agency has put out a similar advisory.
Still, because many were doubtful, Drucker said he and his team launched the study.
In fact, he said one of the cardiologists on the study team shared that he wasn't aware of a possible link, and that many doctors have been skeptical of the advisories.
His hope was to disprove the theory of the cancer risk, Drucker said.
It went the other way.
“We were hoping the finding would be this wasn’t a risk,” he said. “But it was.”
Knowing the risk
The study looked at more than 300,000 people ages 66 and older who had been prescribed blood pressure medications between 1998 and 2017.
Researchers said that those prescribed thiazide diuretics had a 53 percent higher rate of advanced non-melanoma cancer and a 60 percent higher rate of melanoma than those prescribed other blood pressure medications.
“Particularly for someone who has other skin cancer risk factors, [this is good information to know,” Drucker added.
In addition, he said, anyone who's taking blood pressure medication for an extended period of time should consider this possible risk as well.
Anyone taking those medications should speak with their prescribing medical team to discuss possible risks and if they need to make a change to another medication, Drucker continued.
Drucker said he hopes the study helps medical personnel understand the risk. But since those medications had already been given regulatory warnings in the past, he wonders if another study is needed.
“An area for future study could be: What has the impact of regulatory warnings been (on prescribers),” he said.
Another dermatologist's view
Dr. Adam Friedman, professor and chair of dermatology at George Washington University in Washington, D.C., and a spokesman for the American Academy of Dermatology (AAD), said that while this study didn’t bring any new insight, he does believe it can have a substantial impact outside his field.
“This (information) is no surprise to me whatsoever,” he said.
The strength he sees in the study?
“It’s size,” he told Healthline. “It’s one thing to assume that a drug can have an interaction that needs more thought or action, but data like this (takes it beyond assumption).”
Friedman said he hopes these study results push non-dermatology doctors to have conversations around drug interactions with skin and think more about it since many drugs prescribed (such as antibiotics) react with the sun.
“In our own practice, we think a lot about these things when treating,” he said. “But I believe that conversation is not happening (in other medical settings).”
“Hopefully, this message gets out to the world,” he added.
Friedman also hopes it pushes medical schools to teach students more thoroughly about the skin.
“It brings up an even bigger issue,” he said. “In med school, dermatology is pushed aside (in the learning process). Sun protective advice needs to be universal.”
Friedman noted there's plenty of information out there.
“There are lots of resources that are easy to access,” he said, pointing to the AAD website.
As for the general public, Friedman suggests talking with your prescribing doctor if you're taking the drugs in question, as well as asking about all medications and skin and sun interactions.
“Lots of drugs [interact with the sun],” he said. “What’s unique about this one is this is a long-term drug. So it warrants discussion.”