Can anyone explain the difference to me? I know one is prescription, the other OTC.
Thanks.

Xyzal is made with a derivative of the active ingredient in Zyrtec - it's basically a way to launch a new prescription drug that is nearly identical to one that is now over-the-counter (the same thing happened when Claritin became OTC and the manufacturer introduced Clarinex which is still a prescription).

To be really specific, Zyrtec's active ingredient is Cetirizine and Xyzal's is a derivative of Cetirizine called Levocetirizine Dihydrochloride.

Thanks. Any opinion as to which is more effective?

No - I've ready that Xyzal may actually make you more tired than Zyrtec - the fact that Zyrtec is over-the-counter means it will be dramatically cheaper than Xyzal (I looked it up online and Xyzal is $2.50 a dose vs. $.66 for Zyrtec) so I'd recommend starting with Zyrtec - it's cheaper and you can get it at any drugstore without a prescription.

Thank you!

If the zyrtec works for you, you can get 90 for $25, including shipping, from Canada.

I've had chronic urticaria for 4 months now and have tried numerous antihistamines and combinations of antihistamines. I recently went to a dermatologist who gave me a script for Xyzal. However, after checking the price and the ingredients, I decided to forget it. It can't be all that different for all the other H1 blockers. IMO, it's just a manufacturer's attempt at marketing a new drug at a high price since so many of the others have gone generic.

Good luck in finding something that works for you.

Thanks. Zyrtec works fine for me, but my doctor wrote me a px for Xyzal, as well.
Glad to know Zyrtec is less expensive, and more readily available.
Thanks for all the responses!