Which is not a 2nd generation anti–histaminic agent ?: (A) Cetirizine, (B) Cyclizine, (C) Loratadine, (D) Fexofenadine
Answer is B. Antihistaminics may be classified into the first generation and the second generation compounds on the basis of CNS penetration and anticholinergic properties. First Generation Anti-histaminics can penetrate the blood-brain barrier and possess additional anticholinergic properties which are lacking in second-generation drugs. Cyclizine is the first generation whereas cetirizine, loratadine and fexofenadine are second generation drugs.