The class of drugs used to treat allergic reactions is
antihistamines
The class of drugs used to treat allergic reactions is antihistamines. Mast cells release substances called histamines which cause inflammation. This results in common allergy symptoms such as itching, sneezing, runny nose and watery eyes. Antihistamines help prevent or relieve allergy symptoms by preventing histamines from attaching to the cells and causing symptoms.