Strategies for dosing and switching antipsychotics for optimal clinical management.

Optimal clinical management of schizophrenia and bipolar disorder can be achieved through careful antipsychotic dosing and, if necessary, switching to another well-chosen antipsychotic using suitable switching strategies. For severely ill patients treated in clinical practice, adequate dosing may not result from following the relatively low dosing levels and abrupt titration schedules typically used in clinical registration trials. Data from recent effectiveness trials, naturalistic studies, and the Roadmap Expert Consensus Survey provide evidence of specific dose levels and titration schedules for antipsychotic agents that may be appropriate in clinical practice. Discontinuation and frequent switching of medication are common among patients treated with antipsychotics, but data suggest that an adequate trial of the first antipsychotic medication should be undertaken before switching to another antipsychotic medication. Making a decision to switch from a typical to an atypical antipsychotic or between atypical antipsychotics should involve consideration of variables relating to the patient, illness, medication, and the patient's environment. Switching can improve efficacy and tolerability but may also result in predictable side effects or withdrawal symptoms, including weight gain and metabolic effects as well as effects associated with prolactin changes. Many side effects that occur during switching are attributable to receptor profiles and antimuscarinic or antihistaminic blockade. Individualized switching strategies that include careful choice of medication, dose, and titration and tapering schedules; management of symptoms; and patient psychoeducation can reduce or treat side effects, increasing the likelihood of a successful switch and greater adherence and efficacy.