woman with allergy

Spring has finally arrived and this also means allergy season is now in full swing… and many allergy sufferers turn to over-the-counter antihistamines for relief. It’s important for people to realize that they need to be careful about what side effects their allergy medication has and if it will impair their driving.

Allergies & Histamines

pollenAccording to WebMD, when your body comes in contact with something you’re allergic to, be it pollen, ragweed, molds, pet dander and dust mites, your body produces a chemical called histamines. Histamines cause nose tissue to swell, and other symptoms including runny nose, watery eyes, redness and itching.

Allergy Medication & Driving

Taking an antihistamine like diphenhydramine — sold as Benadryl — can reduce or block histamines, resulting in relief of allergy symptoms.

driving drowsy due to allergy medication

Drugs like Benadryl state that patients should be warned about engaging in activities that require being mentally alert – such as driving a car. Diphenhydramine has repeatedly been shown to severely impair tracking and reaction time performance in actual on-the-road driving tests.

According to a study in the Annals of Internal Medicine “Diphenhydramine, a sedating antihistamine, may interfere with driving performance at least as much as alcohol does. People should be as cautious about driving after taking sedating antihistamines as they are after using alcohol.”

Tips to Keep in Mind – from the F.D.A.

  • Always follow directions for use and read warnings on the packages of the drug products you purchase.
  • Allergy MedicationSome antihistamines may cause drowsiness, and you need to exercise caution when driving a motor vehicle or operating machinery. Avoid using alcohol, sedatives, and tranquilizers while taking the product because they may increase drowsiness.
  • Know that some antihistamines take longer to work than others. Recognize that you might feel the sedating effects of these medications for some time after you’ve taken them and possibly even the next day.


  • F.D.A.
  • Annals of Internal Medicine
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Paul d’Oliveira

Attorney Paul d’Oliveira has been practicing personal injury and disability law for over 30 years. He started his personal injury law practice in 1989 with two offices in Fall River, MA and East Providence, RI. Today his firm has 16 offices in RI and Southeastern, MA.

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