When the temperature rises and the fresh air beckons, you’ll probably want to head outdoors to soak up some rays. But if you take certain medications, the sun can present dangers you might not suspect. 

Sunlight delivers a heavy dose of ultraviolet (UV) rays, which in some cases could interact with medication in your body and increase the risk of sunburn, rash or heatstroke. “Certain medications contain ingredients that may lead to a chemically induced change within the skin,” says Alyssa Wozniak, PharmD. She’s a clinical instructor at D’Youville School of Pharmacy in Buffalo, New York. 

We spoke with Wozniak and Mohamed A. Jalloh, PharmD, an assistant professor at Touro University California College of Pharmacy, about the risks of mixing sunlight and medication.  

And don’t forget: You can save up to 80% on the medications you take every day with the Optum Perks discount card.  Get yours now.

Q: For people taking prescription medication, what’s the risk of spending time in the sun?

Wozniak: The risk is photosensitivity, which is an increased sensitivity to sunlight. There are 2 main types of photosensitivity reactions: phototoxicity and photoallergy. 

Phototoxicity involves skin irritation that appears within a few hours of sun exposure. It results from tissue damage that occurs when the sun’s ultraviolet rays are absorbed by certain medications. It typically presents as an exaggerated sunburn. 

 A photoallergy is a delayed allergic reaction that can sometimes happen days after sun exposure. After absorbing UV rays, a change in the structure of the medication occurs. Then the body creates antibodies. The next time the person takes the same medication, their body reacts with an itchy inflammatory response. It often looks like an eczema-type rash.   

Q: Besides sunburn and rash, are there any other symptoms? 

Wozniak: Certain medications may also limit the body’s ability to respond to heat. They do this in a few ways. One is that they might reduce your ability to produce sweat, the key to temperature regulation. They could also elevate the body’s base temperature or make you dehydrated. Any of these could add to your risk of heat-related illnesses. In some cases, this can be very dangerous. 

You should always drink plenty of fluids when you’re outside in the sunlight. This will help you avoid overheating. 

(Urine is one of the best indicators of dehydration. Learn more with this 2-second health check you can do every day.)  

Q: Which medications cause a reaction to the sun?  

Wozniak: There are 6 main types of medication you should be aware of (click each drug name to access coupons instantly):

  •  Retinoid acne medications such as  tretinoin (Retin-A®): These can raise your sensitivity to UV light. People who use these tend to burn easily, often on their face. 
  • Thiazide diuretics such as  hydrochlorothiazide (Microzide®):These can also make you sunburn more easily. In addition, they can cause water loss, which can lead to lower blood pressure. Patients on diuretics should stay well-hydrated when they’re in the sunlight. 
  • Nonsteroidal anti-inflammatory (NSAIDs) medications such as  piroxicam (Feldene®): It is not well understood how NSAIDs react with the sun. But you could get a bad sunburn (phototoxicity) or an itchy rash reaction (photoallergy). 
  • Antiarrhythmic medications such as  amiodarone (Pacerone®): Again, these can make you sunburn more easily. With long-term use and prolonged sun exposure, especially in patients with fair complexions, your skin may discolor to a blue-gray hue. 
  • Certain antibiotics: These especially include tetracyclines such as doxycycline, fluoroquinolones such as ciprofloxacin (Cipro®) and sulfonamides such as sulfamethoxazole-trimethoprim. Reactions range from mild phototoxicity to eczema-like itchy rashes. Ciprofloxacin, for instance, responds to UV light by making compounds that attach to proteins in the body’s cells. These start immune reactions that range from exaggerated sunburn to sun rashes. 
  • Sulfonylurea diabetes medications such as  glipizide (Glucotrol®): People on this type of diabetes medication can have varied reactions to sunlight. But for those who are sensitive, it can be an allergic rash-type reaction.

A graphic listing 6 medications that can cause sun sensitivity: Microzide, Glucotrol, Pacerone, Feldene, Cipro, Retin-A.

Q: How can you protect yourself from medication reactions in the sun?

 Jalloh: There’s a lot you can do. If you take a medication that reacts with sunlight, you should limit your time outdoors between 10 a.m. and 4 p.m., which is when UV rays are strongest. 

When you do go outdoors, wear long sleeves, a hat and sunglasses. And cover your exposed skin with a broad-spectrum sunscreen with a minimum SPF of at least 30. You should put this on 15 to 30 minutes before entering the sun and reapply it every 2 hours while you’re outside. (Learn how sunscreen works with Optum Perks’ guide to SPF.)

It’s worth noting that UV light is strongest at the equator, so take extra precautions if you plan to visit someplace tropical. And of course, always avoid tanning beds. 

Finally, be sure to ask about sun sensitivity when you pick up your medication. Your pharmacist will be able to offer advice on the best time to take it. For example, certain medications may be active for only 6 to 8 hours. A pharmacist might suggest that you take medication before bedtime so you won’t have to worry as much about side effects during the day. 

While you’re at the pharmacy, be sure to present your Optum Perks savings coupons. You can find them all in the Optum Perks app.