Sunburn is a serious matter. Exposure to the sun's ultraviolet (UV) rays is a known risk factor in skin cancer. The American Cancer Society estimates there will be 62,000 new cases of melanoma, the most serious form of skin cancer, in 2006. The death rate has increased 50 percent since 1973. WebMD talked with two experts about medications that heighten your risk for sunburn and how to stay safe in the sun.
Shedding Light On The Subject
Heightened sensitivity to sun, or a phototoxic reaction, occurs when ultraviolet rays interact with certain chemicals in medications. Even after you have stopped taking a drug, its effects may linger.
"Depending on the type of drug and how long you've been taking it, it can remain in your system from one to five days," says Bill Bailey, RPh, director of specialized care centers for Medicine Shoppe in St. Louis. "To be on the safe side, always ask the pharmacist about the effects of your medications on sun exposure. They'll go online and get current, accurate information," he says.
You don't even have to go out in the sun to experience the complications of medications. You could easily get sunburned in a tanning salon, says dermatologist Craig Eichler, M.D. "There have been some bad cases. Tanning booths primarily emit UVA rays, and that's what medications mainly interact with."
And here's another little-known fact about UV rays: They penetrate water. "Swimmers don't realize they can get sunburned under water," says Eichler. Water also reflects UV rays, which can add to your exposure.
SPF, UVA, UVB, And Some Good News
There's a debate over whether sunscreens with high SPF ratings provide any more protection than one rated SPF 15. "I recommend SPF 15. The stronger sunscreens often give people a false sense of security," says Bailey.
Eichler says SPF 15 blocks 92 percent of UVB rays, while SPF 30 blocks 97 percent. "SPF 15 is fine for going to and from the store, but use SPF 30 for longer sun exposure or if you're taking medications."
Whether you use sunscreens with SPF 15 or 45 ratings, you're buying protection from UVB rays, says Eichler, who is with The Cleveland Clinic Florida in Naples, Fla. For protection against UVA rays, a product must contain one of the following active ingredients: zinc oxide, titanium dioxide, or avobenzone (Parsol 1789). "A problem is that these ingredients aren't stable for a very long time."
That's one reason he's glad to see that the FDA has just approved ecamsule, a broad-spectrum sunscreen that has been marketed since 1993 as Mexoryl SX in Europe and Canada. It protects against both UVA and UVB rays and has an SPF 15 rating. It is expected to become available in the U.S. over the counter sometime in the fall as Anthelios SX.
Eichler recommends reapplying sunscreen every couple of hours and making sure to use enough. "Most people use at best half of what they need. If you put it on too thin, it doesn't give you protection." The American Cancer Society says the average adult should use about a palm-full of sunscreen to cover the arms, legs, neck, and face.
The key to effective sunscreen use is to reapply it often. Bailey advises applying it one-half hour before you go into the sun, and every half hour you're exposed. "Sunscreen wears off when you're sweating or in the water. Remember to cover your hands and feet with sunscreen, too."
Both experts tell WebMD you can't rely on sunscreen alone. Wear a hat, cover up, and avoid reflected rays from sand, concrete, and metal, which can reach you even if you've blocked the sun with an umbrella. Also stay out of the sun during the peak hours of 10 a.m. to 3 p.m.
SOURCES: News release, U.S. Food and Drug Administration. Bill Bailey, RPh, director, specialized care centers, Medicine Shoppe, St. Louis. Craig Eichler, M.D., Cleveland Clinic Florida, Naples. American Cancer Society Web site.
By Leanna Skarnulis
Reviewed by Louise Chang, M.D
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