Most of all, you're feeling frustrated. If you're a seasonal allergy sufferer you might think that the first itchy, stuffy nose of the season is your cue to start taking your medicine. According to Dr. Monte Keen of Columbia Presbyterian Medical Center in New York City, however, it can take one hour or longer for your antihistamine to start working and regular use to maintain effective relief. And in the meantime you want to breathe right now. How Medicines Work Antihistamines block the effects of histamine, which is released by the mast cells and causes allergy symptoms.
Antihistamines usually work well for sneezing and itchy eyes, throat and nose.
Decongestants shrink swollen nasal tissues. Allegra-D is indicated for seasonal allergic rhinitis with nasal congestion in patients 12 and older. Also, let your doctor know before you take Allegra-D if you have high blood pressure, diabetes, heart disease, glaucoma, thyroid disease, impaired kidney function, or symptoms of an enlarged prostate such as difficulty urinating. Additional important information . Keep a supply of allergy medicine in the house.