The Sun and Your Medications
Several common over-the-counter and prescription medications can trigger toxic and allergic reactions to natural or artificial ultraviolet light — a condition called photosensitivity. Drugs such as birth control pills, allergy pills, statins and blood pressure medications may cause symptoms such as rashes, blisters or heatstroke.
Most people look forward to spending time outdoors during the sunny days of summer. But for those who take certain medications, too much fun in the sun can cause serious side effects such as severe sunburns, rashes and heatstroke.
That’s because several common over-the-counter and prescription drugs — including antihistamines, cholesterol-lowering drugs, pain relievers, diabetes medications and antibiotics — can make the skin more sensitive to sunlight, a condition called photosensitivity.
“We don’t have accurate numbers about the incidence of photosensitivity reactions due to medications in general in the United States,” pharmacist Mireille Hobeika told Drugwatch. “But what we know for sure is that photosensitivity reactions due to medications occur more often in men than in women.”
Photosensitivity can happen at all times of the year, but cases peak in the summertime. People often end up in the emergency room. Some drugs may also increase side effects of heat exposure.
“We see this a lot. It’s very common,” ER physician Robert Glatter told AARP. “People will take [antibiotics] and then go to the beach, and we’ll see them come in beet red with a head-to-toe sunburn.”
The good news is that with the right precautions people can still enjoy some time outdoors and minimize harmful side effects.
How Do Drugs Cause Photosensitivity?
Photosensitivity occurs when chemicals in certain drugs absorb ultraviolet light, leading to a buildup of damaging compounds in the skin. Pharmacists call drugs that trigger these reactions “photosensitizers.”
Two types of ultraviolet light can cause photosensitivity. Ultraviolet-A (UVA) rays — “long” wave — cause most reactions, but ultraviolet-B (UVB) rays — “short” wave — can also cause problems. These rays can come from natural or artificial ultraviolet light sources, such as a tanning bed.
There are two types of photosensitivity: phototoxocity and photoallergy.
Phototoxicity is the most common form of drug-induced photosensitivity, according to Hobeika.
“It may occur when the skin is exposed to the sun after certain drugs are injected, taken orally, or applied to the skin,” she told Drugwatch. “When the drug absorbs the light, it gets activated which will result in the formation of compounds that will have a direct damaging effect on the membranes of the skin cells, and in some cases on the DNA of the skin cells.”
“Phototoxic responses often occur within minutes or hours of light exposure.”
This causes an inflammatory response. The most common symptom is an exaggerated sunburn. Typically, the reaction is limited to the area of the skin exposed to the sun, said Hobeika.
“Phototoxic responses often occur within minutes or hours of light exposure,” she added.
Exposure to sun also triggers photoallergy, but it is not as common as phototoxcity. While phototoxcity can occur within minutes of sun exposure, photoallergic reactions may occur several days after exposure.
“[Reactions] can be triggered by products applied to the skin or medicines taken by mouth or injected. It all begins when the ultraviolet (UV) light of the sun causes a structural change in the drug,” according to Hobeika. “This will lead to the development of … an antigen.”
Antigens are compounds recognized as foreign substances by the body. The immune system attacks the antigens, leading to an allergic reaction. These reactions may affect the area of sun exposure or may spread to bigger areas on the body.
Photoallergic reactions may occur with smaller doses of a drug than with photosensitivity.
Photosensitivity usually affects the skin, but some drugs can also increase the negative effects of heat and lead to heatstroke or dehydration. These drugs reduce the ability to sweat, increase urination, and decrease thirst.
Symptoms to Look Out For
Symptoms of photosensitivity affect the skin, while other conditions such as heatstroke affect the entire body. It’s important to note that not all people suffer from photosensitivity or heat sensitivity. A person may also suffer from a reaction once and never have it again.
Symptoms can range from mild to severe depending on the amount of sun exposure, type of drug and drug dosage.
For example, antibiotics are among the biggest offenders. Rachel Brummert, a trained health advocate and Special Government Employee at the FDA, suffered a number of side effects from Levaquin (levofloxacin), including photosensitivity.
“My sunburns are more severe than they used to be in a shorter amount of time, and I develop blisters within about 12 hours after exposure if I’m in the sun more than 10 minutes,” Brummert told Drugwatch.
- Sunburn-like symptoms
- Brown or blue-gray discoloration
- Blisters that resemble hives
- Dry patches
Drugs that make you more sensitive to heat can cause muscle cramps, heat exhaustion, heat stroke and dehydration.
Medications that Increase Sun Sensitivity
Over 100 substances, swallowed or applied to the skin, can cause photosensitivity, according to the Merck Manual. Some of these drugs include warnings on their labels for photosensitivity.
“There are many medications that increase sensitivity to the sun,” said certified holistic health practitioner and nutritionist Rebecca Montrone. “What’s worse, many people combine medications that cause this problem, thereby multiplying the effect. [These include] statin drugs, non-steroidal anti-inflammatories such as Motrin and Aleve and diuretics.”
Depending on the drug, the frequency and risk may be higher.
“Drugs that belong to the tetracycline [antibiotics] group have been reported to induce photosensitivity in a much higher percentage of patients (7 to 90 percent depending on the drug) than the drugs belonging to the quinolone group (1 to 19 percent),” Hoebika said.
- Alpha-hydroxy acids in cosmetics
- Antibiotics (ciprofloxacin, levofloxacin, ofloxacin, doxycycline, tetracycline, trimethoprim)
- Antifungals (flucytosine, griseofulvin, voricanozole)
- Antihistamines (cetirizine, diphenhydramine, loratadine, promethazine, cyproheptadine)
- Antipsychotic drugs (haloperidol, olanzapine, quetiapine, risperidone)
- Cardiac or blood pressure medications (amiodarone and quinidine; calcium channel blockers such as nifedipine and diltiazem; ACE inhibitors such as enalapril; and angiotensin II receptor antagonists such as valsartan)
- Chemotherapy drugs (docetaxel, nilotonib and others)
- Cholesterol lowering drugs (simvastatin, atorvastatin, lovastatin, pravastatin)
- Diuretics (thiazide diuretics: hydrochlorothiazide, chlorthalidone, chlorothiazide.; other diuretics: furosemide and triamterene)
- Non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, celecoxib, piroxicam, ketoprofen)
- Oral contraceptives and estrogens
- Overactive-bladder treatments (anticholinergics such as oxybutynin, and solifenacin)
- Phenothiazines (tranquilizers, anti-emetics: examples, chlorpromazine, fluphenazine, promethazine, thioridazine, prochloroperazine)
- Psoralens (methoxsalen, trioxsalen)
- Retinoids (acitretin, isotretinoin)
- Sulfonamides (acetazolamide, sulfadiazine, sulfamethizole, sulfamethoxazole, sulfapyridine, sulfasalazine, sulfasoxazole)
- Sulfonylureas for type 2 diabetes (glipizide, glyburide)
- Tricyclic antidepressants (amitriptyline, nortriptyline, doxepin, imipramine)
This is not a complete list. Always check with a pharmacist and read the drug labels before spending time out in the sun.
Diagnosis and Treatment
There are no specific tests for photosensitivity, according to Merck Manual. But doctors can generally diagnose the condition if they notice rashes or other skin problems only in areas exposed to sunlight. The medical professional will review a person’s medical history and any drugs taken by mouth or applied to the skin.
In some cases, doctors may have to rule out other diseases that can cause reactions to sunlight, such as systemic lupus erythematosus. The medical provider may perform a patch test and expose an area of skin to UV light when the patient is not taking any photosensitizing drugs.
“Phototoxic responses can be reversed by withdrawal or substitution of the drug. Topical corticosteroids and cool compresses may also calm drug-induced photosensitivity.”
Most cases resolve without treatment, according to Merck Manual. Treatment is usually fairly simple and meant just to control symptoms.
“Patients who experience drug-induced photosensitivity should first identify and avoid the drug, cream or agent that caused it. Phototoxic responses can be reversed by withdrawal or substitution of the drug,” Hobeika said. “Topical corticosteroids and cool compresses may also calm drug-induced photosensitivity.”
The most severe cases may require systemic corticosteroids.
Sun Safety Tips
Being mindful of sun exposure and staying away from excessive sun and heat are the best ways to avoid photosensitivity. Luckily, photosensitivity is not typically fatal, though heatstroke and other heat-induced illnesses can be serious.
Seek Shade and Wear Protective Clothing
The FDA recommends that people seek shade, especially between the hours of 10 a.m. and 2 p.m. The agency reminds people that the sun’s rays may be stronger when reflected off water, sand and snow.
Keep in mind that several things can affect the amount of UV radiation exposure: time of day, season, geographic location, altitude, and weather conditions (cloudy day versus clear).
“I need to wear sunglasses outside … because my eyes are sensitive. I limit my time in the sun to the late afternoon if I can’t avoid it during the day.”
People can wear long-sleeved shirts, pants, sunglasses and broad-brimmed hats to reduce sun exposure.
“I need to wear sunglasses outside … because my eyes are sensitive,” Brummert said. “I limit my time in the sun to the late afternoon if I can’t avoid it during the day.”
People with jobs in construction or others that require plenty of time outdoors should ask their doctor about the possibility of adjusting their medication dosage or timing, according to the Laborers’ Health & Safety Fund of North America.
In addition, it’s a good idea to use a broad-spectrum sunscreen that protects against UVA and UVB radiation. The FDA recommends at least an SPF 15, but SPF 30 or higher is preferable.
In order for a sunscreen to be effective, people have to apply it and reapply it as directed.
Some sunscreen ingredients may actually cause photosensitivity themselves, and the FDA recently released a blog post about sunscreen chemicals and skin absorption. The agency isn’t sure how much absorption is safe without more tests. But the FDA does not recommend that people stop using sunscreen.
For people who would rather use a more natural or organic sunscreen, Montrone recommends a few that are safe and effective.
- Attitude 100% Mineral Sunscreen, Fragrance Free, SPF 30
- All Good Sunstick, Unscented, SPF 30
- Aveeno Baby Continuous Protection Lotion Sunscreen, Sensitive Skin, SPF 50
- Badger Active Natural Mineral Sunscreen Cream, Unscented, SPF 30
- Goddess Garden Sport Mineral Sunscreen Lotion, SPF 50
- Just Skin Food Baby Beach Bum Sunscreen Stick, SPF 31
- Kabana Organic Skincare Green Screen Sunscreen Lotion, Original, SPF 32
- Poofy Organics The Sunscreen Lotion, SPF 30
- Poofy Organics The Sunscreen Stick, SPF 30
- Sunology Mineral Sunscreen, Body, SPF 50
- Thinksport Sunscreen, SPF 50+
- Waxhead Sun Defense Zinc Oxide Sunscreen Stick, SPF 30
Protect Against Heat-Related Illness
Staying hydrated with water and sports drinks will help keep your body cool and avoid dehydration. Avoid drinking beverages such as alcohol and caffeine — both will work against efforts to hydrate.
Watch for signs of heat-related illness. These include a headache, racing pulse, rapid breathing, light-headedness, nausea or weakness. If these symptoms are present, lie down in a cool room with your feet above your heart, according to Consumer Reports.
Apply wet cloths to your skin to bring your body temperature down. Your can also drink a half-cup of a sports drink or a solution of 1 teaspoon of salt in a quart of water every 15 minutes.
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