The people who were intoxicated drove as though they were.And the people who took Benadryl looked normal, but drove like the drunks," says Steven H.And there is no evidence, Bender says, that either type is better at suppressing histamine, which causes allergic reactions."My advice is that you shouldn't make up your mind based exclusively on what you hear in advertising," says Bender, a psychologist who serves as an assembly chairman of the American Thoracic Society.The question, is it necessary to spend the extra money?" These newer products, which include Allegra, Zyrtec, and Claritin, generally cost between 10 to 20 times as much as the older, "first-generation" products.Most of the second-generation antihistamines have been shown to benefit chronic idiopathic urticaria.Once-daily fexofenadine appears to offer effective and well-tolerated relief from the symptoms of this illness.
That study was sponsored by the company that manufactures Allegra.The difference between them is really blurred." "Under some circumstances, the nonsedating formulas do cause sedation and in some cases, these sedating formulas do not," he tells Web MD."In some studies we reviewed, some people actually experienced more sedation with the newer, nonsedating formulas than with the older, sedating products.Antihistamines work by blocking the action of histamine which the body produces as part of its natural defences.Histamine is released as a reaction to foreign substances (allergens), and starts a chain reaction that leads to the release of other chemicals that add to the allergic response. There are two different types of antihistamine; sedating antihistamines, which can enter the brain and cause drowsiness and non-sedating antihistamines which do not.