What is the difference between desloratidine and loratidine? Is one better than the other?

Take one, get both. When you take loratidine, your liver breaks it down to desloratine which is actually responsible for the anti-histamine effects you need. Desloratidine has a much longer effect (28 hours) than loratidine (8 hours) which is why loratidine lasts such a long time.