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What is Which is not a 2nd generation anti-histaminic agent? and explain in detail?
Ans (B) Cyclizine(Ref: Goodman and Gilman 12th/e p921,922)Antihistaminics may be classified into first generation and second generation compounds on the basis of CNS penetration and anticholinergic properties. First Generation Anti-histaminics can penetrate blood brain barrier and possess additional anticholinergic properties which are lacking in second generation drugs. Cyclizine is a first generation whereas cetirizine, loratadine and fexofenadine are second generation drugs.