Symptoms include nasal congestion, a runny nose, sneezing, and itchy and watery eyes.Antihistamines work by blocking histamine, which is the main trigger of allergy symptoms in the nose, airways, and skin.There’s also been a long-standing debate about just how much better they are than older, less expensive antihistamines and whether they’re worth the extra cost. Most doctors advise their patients to use the newer pills, while others think their patients do just as well taking the older, nonprescription drugs.
While the second-generation antihistamines can help relieve allergy symptoms, they usually don’t clear them up entirely.
Because of that, some allergy sufferers may choose instead to take one of the second-generation antihistamine medications.
And while the newer, second-generation antihistamines are generally safe and are less likely to cause sedation and drowsiness compared to the older, first-generation antihistamines, such as Benadryl Allergy (generic name diphenhydramine), Chlor-Trimeton Allergy, and Dimetapp Allergy, those problems can still occur, especially at higher doses.
In people who have allergies, the body’s immune system overreacts when exposed to otherwise harmless substances—animal dander, dust mites, mold spores, or pollen—by releasing excessive amounts histamine.
That chemical is a part of the body’s natural defense mechanisms, and it works in part by widening blood vessels, which also causes congestion and sneezing. About 17.6 million adults and 6.6 million children in the U. were diagnosed with allergies in 2012, according to the Centers for Disease Control and Prevention.