4 ways medications make you more vulnerable to heat and sun

By Bianca Barr Tunno, AccuWeather staff writer 

 

Certain medications may make some people more susceptible to heat-related illness, but pharmacists say you can counteract these side effects with a few simple choices when you’re in the sun.

You should continue to take your prescription or over-the-counter medications, but experts suggest asking a doctor or pharmacist about how the drugs affect your body when you are outside in hot, bright sunlight.

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Medications can decrease blood flow to the skin
Some medications can constrict the blood vessels and reduce blood flow to the skin, according to Emily Holm, PharmD., a Mayo Clinic Health System pharmacist. The body needs to maintain a core temperature. So in a hot environment, blood flow needs to be increased to the skin to radiate heat into the atmosphere, which cools the body down.
Over-the-counter decongestants such as Sudafed (phenylephrine) and prescription stimulants for attention-deficit/hyperactivity disorder, like Adderall or Concerta, could interfere with a patient’s ability to cool down.
Beta blockers, like metoprolol, can also make it harder to regulate body temperature.
“To radiate heat out of the body and increase the blood flow to the skin, your heart is going to have to work harder and pump faster,” Holm said. “If you are on medications such as beta blockers for either blood pressure or heart arrhythmia, those medications slow the heart rate down and that can also block that blood from increasing blood flow to the skin.”
Medications can stop you from sweating
According to Holm, drugs with anticholinergic side effects will dry you up in general. When you can’t sweat, you can’t cool down.
This category includes over-the-counter medications for cold, cough or allergies, such Benadryl (diphenhydramine); tricyclic antidepressants, like nortriptyline; and medications for bladder spasms, such as oxybutynin.
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Medications can increase sunburn risk
The Food and Drug Administration defines photosensitivity as a chemically induced change in the skin that makes an individual unusually sensitive to light. Some medications contain ingredients that might increase the risk of painful sunburn, rash or other sun-related reaction.
Take precautions if your medication falls in any of these categories, identified by the FDA: antihistamines, coal tar and derivatives, birth control pills and female sex hormones, nonsteroidal anti-inflammatory drugs (NSAIDs), phenothiazines, psoralens, sulfonamides, sulfonylureas, thiazide diuretics, tetracyclines and trycyclic antidepressants.
Medications can lead to dehydration
Dehydration can occur easily without influence of medication, so be particularly mindful of your water intake if you are currently taking diuretics.
Sometimes called water pills, diuretics help rid your body of salt and water to lower blood pressure and swelling, according to experts at the Mayo Clinic. The medicine can lead to dehydration because it causes increased urination.
Holm told AccuWeather that patients taking diuretics may also be at an increased risk for sunburn, giving this class of medication a two-fold reason to stay out of the sun.
“Patients might feel like they can’t tolerate the sun or get dizzy and tired outside, so it is important to stay hydrated,” said Holm. “Stay in the shade if you are on any of those types of medications.”
How can you protect yourself?
Holm shared a simple list of things to do to keep yourself safe in hot weather:
1. Always wear at least 30 SPF sunscreen.
2. Stay hydrated with generally 64 ounces of water per day, unless your doctor tells you otherwise.
3. Complete yard work or outdoor chores early in the morning or in the evening when the temperatures are lower.
4. Watch for the following symptoms: dizziness, light headedness, headaches, weakness and nausea. If these develop, find a cool place to rest and drink water.

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