While they sound similar, Piriton and Piriteze contain different active ingredients.
Piriton contains chlorphenamine maleate while Piriteze contains cetirizine hydrochloride.
Another key difference is that Piriton is classed as a drowsy or sedating histamine, while Piriteze is classed as a non-drowsy or non-sedating antihistamine.
If you are unsure whether Piriton or Piriteze are suitable for you, speak to your doctor or a pharmacist.