Medications that treat respiratory allergies work by controlling the way the immune system reacts to allergens. The most common medications used to treat allergies contain antihistamines, which are available in many forms and are used to stop the effect of histamines. For more severe allergies, medications that contain mast cell stabilizers (which help stop the production of histamines) or corticosteroids (which stop inflammation) may be helpful. Medications for allergies include over-the-counter and prescription eye drops, nasal sprays, lotions, and oral medications. Talk to your doctor to discuss the best treatments options for your respiratory allergies.