Attenuation of cutaneous reactivity to histamine by cetirizine and dexchlorpheniramine

A double-blind cross-over study was performed in 12 healthy female volunteers comparing cetirizine di-HCl (10 mg) and sustained release dexchlorpheniramine maleate (6 mg) with respect to attentuation of histamine-induced skin wheals and subjective central nervous system (CNS) effects. Cetirizine was significantly more effective than dexchlorpheniramine in suppressing the size of wheals from 2 to 24 h after drug administration. In fact, at 24 h cetirizine was still as effective as 2 h after ingestion. Ten subjects receiving dexchlorpheniramine reported subjective symptoms relating to CNS depression, in contrast to only one subject given cetirizine.