Whenever antipsychotic medication is not effective, the first intervention should be to check adherence. If the intake of the oral medication is “relatively” sure and no relevant side effect occurs, the dosage should be increased, if necessary to the maximal tolerated dosage. If side effects do not allow any further increase of the dosage and the antipsychotic drug is taken without any relevant improvement, switching to another antipsychotic is an option most often used. Several issues should be considered:

Change only one drug at a time, switch to an antipsychotic with a different pharmacological profile, ask the patient for his/her collaboration, document psychopathology and tolerability before switching and plan to do again two to four weeks after switching to assess success of switching. The switching strategy has been investigated in several studies and no major difference has been found. However, cross tapering for a period of three to seven days is most often used and probably the safest procedure. The efficacy of switching the antipsychotic, although often used in daily practice, has not well been investigated yet. The few clinical studies will be presented. Data can be summarized: to switch from the first atypical antipsychotic to the second, is effective in 20 to 30%, the switching to a third atypical antipsychotic (if not clozapine) is very seldom successful. After two unsuccessful attempts a switch to clozapine should be thoroughly considered.