About hydroxyzinesa first-generation h1 antagonist,piperazine derivative, antihistamine, antiemetic, anxiolytic, sedative-hypnotic.smechanism of action of hydroxyzineshydroxyzine compete with histamine for h1receptor.it blocks the histamine action s on the effector`s cell surface. it has sedative, antiemetic, antimuscarinic and spasmolytic property. santianxiety action: hydroxyzine produces its anxiolytic action through suppression of activity at subcortical levels. sinteractions for hydroxyzinescns depressants (barbiturates, hypnotics, opiod analgesics): potentiation of cns depressant effect. smaois, tcas, atropine: potentiate antimuscarinic effects. saminoglycosides: ototoxicity of aminoglycosides masked. saminophyllline, benzyl penicillin, chloramphenicol: incompatible with these drugs. sincompatibility reported with aminophylline, benzyl penicillin salts, chloramphenicol, sodium succinate, thioridazine and some soluble barbiturates.