Ketotifen....can this be used as a subsitute?

Zyrtec:

http://www.pfizer.com/download/uspi_zyrtec.pdf


Whats the Clen guru's thoughts on this?


Thanks

Just a blurb from the PDF>


CLINICAL PHARMACOLOGY
Mechanism of Actions: Cetirizine, a human metabolite of hydroxyzine, is an antihistamine; its principal effects are mediated via selective inhibition of peripheral H1 receptors. The antihistaminic activity of cetirizine has been clearly documented in a variety of animal and human models. In vivo and ex vivo animal models have shown negligible anticholinergic and antiserotonergic activity. In clinical studies, however, dry mouth was more common with