<prompt> Which is not a 2nd generation anti-histamine agentsCetirizineCyclizineLoratidineFexofenadine  <response>: Anti histamines are classified into first generation and second generation compounds on the basis of CNS penetration and anti cholinergic propeies. First generation anti-histamine can penetrate blood brain barrier and possess additional anti cholinergic propeies which are lacking in second generation drugs. Cyclizine is a first generation where as cetrizine, loratidine and fexofenadine are second generation drugs Refer Goodman Gilman 12e p921 