Why do certain medications come with a warning that they can make people more sensitive to ultraviolet light? It’s because too much sun while on those meds can raise skin cancer risks.
A recent study investigated the risk of developing non-melanoma skin cancer after taking medications that cause sensitivity when exposed to ultraviolet light. Researchers found that certain antibiotics and blood pressure medications may increase the odds of developing basal and squamous cell carcinoma, especially in patients who frequently get sunburns instead of tanning.
Margaret R. Karagas, PhD, professor of biostatistics and epidemiology at the Geisel School of Medicine at Dartmouth in New Hampshire, led a team to investigate whether photosensitizing medications play a role in the development of non-melanoma skin cancers.
Photosensitizing medications make people extra sensitive to light and put them at a higher risk for sunburn. The non-melanoma skin cancers in this study were basal cell and squamous cell carcinoma. Ultraviolet light is a risk factor for both of these common skin cancers.
It’s important to note that some people are genetically more prone to sunburns while other people are more prone to tan from sun exposure. Sun sensitivity, which results in sunburns, is also a risk factor for developing non-melanoma skin cancers.
Many different types and classes of medication have photosensitivity warnings, ranging from antibiotics to long-term blood pressure control medications.
For this study, researchers looked at 5,072 people in New Hampshire to see if taking photosensitizing medications increased the risk of non-melanoma skin cancers. The group had 1,567 people with basal cell carcinoma, 1,599 people with squamous cell carcinoma and a comparison group of 1,906 people without skin cancer.
Researchers found people with both basal and squamous cell carcinomas had more sunburns in the past than people in the comparison group.
Results showed that people who used a photosensitizing medication had slightly increased odds of developing non-melanoma skin cancer. Specifically, the odds were 1.2 times greater for developing basal and squamous cell carcinoma.
The odds of developing squamous cell carcinoma were 1.5 times greater for people taking photosensitive medications that were potent enough to be considered phototoxic and for those who had a tendency to get sunburned rather than tan.
The same increase in odds were not found with basal cell carcinoma from taking phototoxic medication, but family history of basal cell carcinoma did appear to play a role.
Specifically, taking photosensitive antimicrobial types of medications, such as tetracycline antibiotics, for longer than one year doubled the odds of developing basal cell carcinoma before the age of 50.
Researchers also found that patients who had taken cardiovascular medications or diuretics had 1.3 times greater odds of developing squamous cell carcinoma.
The authors concluded that the use of photosensitive medications may increase the risk of basal and squamous cell carcinoma, especially in people who already have a tendency to sunburn.
This study was published in January in The Journal of Investigative Dermatology.
The National Cancer Institute and the National Institutes of Health provided funding for this study. No conflicts of interest were found.