Is xyzal unlikely to work for someone for whom zyrtec does not work?

Maybe, maybe not.: Some feel it may work when Zyrtec does not. Try it and see. Also, best to eliminate cause of allergies and overall allergy burden. So get rid of fragrances, aerosols, any type of smoke exposure (inc. candles), as well as avoid known triggers. See other nasal and respiratory tract irritants here, these apply to adults/kids: http://tinyurl.com/zwofpz7 and http://tinyurl.com/mgrrrsj

Worth a Trial: Both are second generation antihistamines and have the same mode of action.But these are different compounds and for some people swithing helps with their symptoms.It is worth trying.Xyzal is available by prescription and zyrtec is over the counter