Mesoridazine (Serentil) is a piperidine neuroleptic drug belonging to the class of drugs called phenothiazines, used in the treatment of schizophrenia. It is a metabolite of thioridazine. The drug's name is derived from the methylsulfoxy and piperidine functional groups in its chemical structure. Mesoridazine (Serentil) is a piperidine neuroleptic drug belonging to the class of drugs called phenothiazines, used in the treatment of schizophrenia. It is a metabolite of thioridazine. The drug's name is derived from the methylsulfoxy and piperidine functional groups in its chemical structure.