MONDAY April 12, 2021 (HealthDay News) – Most people are familiar with common sun protection advice, whether it’s wearing and reapplying sunscreen or putting on a hat.
But a new Canadian study finds that for people who take certain blood pressure medications, this advice becomes even more critical because these drugs can increase their sensitivity to the sun’s harmful ultraviolet (UV) rays.
Researchers looked at data from nearly 303,000 adults over the age of 65 in Ontario who were prescribed medication for high blood pressure. The study then compared their skin cancer history to that of more than 605,000 adults who were not taking antihypertensive drugs.
The results showed that certain types of blood pressure medications – called thiazide diuretics – were associated with higher rates of keratinocyte skin cancers, including basal cell carcinoma, squamous cell carcinoma, advanced keratinocyte carcinoma and melanoma.
“Our discovery is not intended to rule out thiazide diuretics for patients,” said study author Dr. Aaron Drucker. He is a Clinical Investigator in the Department of Dermatology, Alpert School of Medicine, Brown University, Providence, RI
“Overall, this is more of a potential indicator for someone who might be at an increased risk for skin cancer, who has had one in the past, or who has really fair skin and a lot of damage. caused by the sun, that it could predispose them to more skin cancer. So, yes, someone like that could consider an alternative, “Drucker said.
Four other blood pressure medications – angiotensin converting enzyme (ACE) inhibitors, beta blockers, angiotensin II receptor blockers (ARBs), and calcium channel blockers – have not shown any effect. association with the risk of skin cancer.
“None of the other antihypertensive drugs are showing the same signal, so in a way we have four negative controls,” Drucker said.
Previous studies had shown an increased risk of skin cancer in people taking the drug, also known as hydrochlorothiazide. This most common thiazide drug has triggered prolonged use warnings by Health Canada, the U.S. Food and Drug Administration, and the European Medicines Agency, the study authors noted.
This new study followed people over time to determine if the risk occurred not only because a person was taking these drugs, but if the cumulative dose or duration could impact their risk of skin cancer. Higher cumulative exposure (taking the drugs over a longer period) was associated with increased rates of skin cancer, the results showed.
“If you take these drugs for just a few years, it doesn’t have a major impact on your cancer risk. But for someone who has been taking, say, 25 milligrams per day of hydrochlorothiazide for 10 years, in our study that person would have a 40% increased risk of keratinocyte carcinoma, “Drucker said. If they were on the same dose for 20 years, the relative risk increased compared to someone who had not taken hydrochlorothiazide. is a 75% increased risk, he added.
“So there’s a big effect of how long you took over the time that I think is really important to spend,” Drucker explained.
Exposure to UV rays is the most important environmental risk factor for skin cancer. Drug-induced phototoxicity can cause cellular damage to the skin, increasing the carcinogenic potential of the sun, the study’s authors noted in the report published on April 12 in the CMAJ.
Dr. John Strasswimmer is a board certified dermatologist in Florida and spokesperson for the Skin Cancer Foundation. He did not participate in the study, but commented on the results.
“Skin cancer is a major cancer on the rise in the United States,” he said. “And, unfortunately, as we get better and better in their treatment, just because of the sheer number of tumors, we also have too many people still dying from skin cancer. And even those who do not die of it. , it becomes a very big [health] problem for them. It really affects their quality of life. “
Strasswimmer said he hopes this study will encourage those who use this common drug to practice good sun protection. There is no safe tan except maybe a spray tan, he added. Any exposure that makes you tan can also cause precancerous and cancerous changes to your skin.
He recommends that you get in the shade when you can. Cover your head. Wear good quality UV protective clothing. And cover these other parts of your body with good quality sunscreen. Remember to reapply as it may go down, Strasswimmer said. People should also be familiar with what skin cancer looks like.
“Skin cancer is an extremely important disease that needs to be taken care of,” he noted. “However, this is not the only one.” He pointed out that heart disease and high blood pressure are silent killers that cause a lot of deaths in the United States. “So I think the last thing we would like to see would be for people to consider stopping their meds,” Strasswimmer said.
“In this scenario, where people could be at a very high risk of developing skin cancer or possibly at high risk for skin cancer, it could certainly prompt a conversation with their primary care physician to find out. if there could be an equivalent change that could be made, ”he suggested.
The US National Cancer Institute has more information on skin cancer.
SOURCES: Aaron Drucker, MD, dermatologist and certified clinical investigator, department of dermatology, Brown University Alpert Medical School, Providence, RI; John Strasswimmer, MD, PhD, certified dermatologist, Delray Beach, Florida, spokesperson, Skin Cancer Foundation, and clinical professor, medicine / science researcher, Florida Atlantic University, Boca Raton, Florida; CMAJ (Journal of the Canadian Medical Association), April 12, 2021