Our answer comes from Mark Bianchi, M.D., ear, nose and throat specialist at Yale Medical Group.
“There are three categories of allergy pills; antihistamines, decongestants, and leukotriene inhibitors. They all work fairly rapidly. I don’t continue the first two for more than a week if they’re not working. Leukotriene inhibitors (i.e. Singulair) may have a more cumulative effect, especially in children who have large tonsils and adenoids.”