Absolutely. Zyrtec (cetirizine) is a 2nd generation antihistamine approved for the treatment of urticaria (hives) and allergic rhinitis . I think an allergic reaction to this medicine is sore throat so if it gets worse stop taking it .
Sometimes with allergies you do not have a runny nose but the drainage goes down the back of your throat instead and it can cause you to have a sore throat. Zyrtec is a antihistimine and if the sore throat is from allergies will help to dry up the drainage thus stopping the sore throat . There of course are other reasons for a sore throat and some of these may require an antibiotic from your Doctor .