Ask Your Pharmacist

June 21, 2017

I had an antibiotic filled and was told that I could be more prone to sun burns while taking it. Should I just wear extra sunscreen?


After a cold, wet spring, summer has finally arrived, and pharmacists are spending more time counseling patients about staying safe in the sun and treating sun burns. Indeed, there are several medications that make your skin more prone to damage with increased exposure to the sun. I’d like to provide a bit of information on what the risks are and how you can appropriately prevent a sunburn, regardless of the medications that you may be taking.

A drug-induced photosensitivity is the term used to describe abnormal reactions of the skin as a result of the suns rays interacting with a medication in your body. Two types can occur. The first is photoallergy which occurs when light causes a medication which is concentrated near the skin to act as an allergen in the body and produce a rash. This is the rarest type of photosensitivity. The other is a phototoxic reaction which describes a chemical reaction that occurs when a drug absorbs UVA light from the sun and causes cellular damage. This reaction, which is more common, normally has a rapid onset and appears as an exaggerated sunburn.

There are several commonly used medications that can cause a drug-induced photosensitivity. Antibiotics such as tetracyclines, sulfonamides (for example, Bactrim), and quinolones (for example, Ciprofloxacin) are well known to cause these reactions.  Thiazide diuretics such as HCTZ and sulfa-containing diabetes medications such as gliclazide and glyburide are widely used and also prone to these reactions. There are numerous other medications that can cause these reactions as well, so be sure to ask your pharmacist if you are concerned about one of yours.

Should a reaction occur, cool compresses may help the symptoms but in some cases your doctor will prescribe topical or oral steroids to reduce the reaction. Antibiotics are normally taken for only a short amount of time but chronic meds causing this reaction may require a switch to a less risky drug or a dose reduction if the problem continues to occur.

Fortunately, there are several measures that can be taken to limit your skin’s sun exposure while still enjoying quality time outdoors this summer. It is important to be aware that the sun’s rays are normally strongest between 10am and 2pm and that clouds and water do not efficiently block them. The best coverage for your skin is dry, tightly woven clothing. A wide brimmed hat is a good idea to keep your head and neck shaded.

For skin that will be exposed to the sun, wearing an appropriate sunscreen is very important. You should select one that offers protection against both UVA rays (can cause early skin aging and skin cancer) and UVB rays (can cause sunburn). You should use at least an SPF 15 and realize that higher SPF numbers provide better protection.  You should apply sunscreen to you and your loved ones at least 15-30 minutes before going into the sun so that can appropriately absorb and reapply at least every two hours, or more often if you are swimming or sweating. It is important to note that no sunscreen is waterproof and even water-resistant ones will wash off quickly if you’re in the water or sweating. 

Pharmacists are trained on sun care and can help you pick out a good product to keep you and your family safe in the sun this summer. We can also help recommend something to treat a burn. Don’t hesitate to ask for help in your pharmacy if you need it.

Ryan Kennedy (BSc., Doctorate of Pharmacy, MBA) is a pharmacist/owner at Jean Coutu in Saint John. His opinions expressed in this newspaper are published for educational and informational purposes only and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment. Send your questions to