4-(p-Chloro-α-phenylbenzyl)-1-piperazineethanol-d4, is the labaled analouge of 4-(p-Chloro-α-phenylbenzyl)-1-piperazineethanol (C377565) that is used in the synthesis of antifungal triazole and imidazole derivatives. Impurity of an intermediate in the formation of Cetrizine.