How do allergy meds work, while having different side effects?
January 14, 2008 10:22 PM Subscribe
How do loratadine and diphenhydramine HCI work? Specifically, how is it that both can help control allergies, yet have different side effects? I'm particularly interested in how loratadine works without causing sleepiness, while a single 25 mg capsule of diphenhydramine is able to knock me out in a matter of minutes.