what over the counter medication is best for an allergic reaction.
A word of caution: It is important to take all medications, including those you obtain over-the-counter, as directed. Using these medications improperly can put you at risk for high blood pressure, stroke, heart attack, and convulsions. Over-the-Counter Antihistamines. Antihistamines are commonly used to treat allergic rhinitis (for example, hay fever) and hives. They block a chemical called histamine, which is produced by your body when you have an allergic reaction. Blocking histamine can help control sneezing, itching, runny nose, and hives. Many people take antihistamine medications proactively â before they think their allergies may flare-up â each allergy season.