Choosing an atypical antipsychotic.

The atypical antipsychotics vary in terms of their pharmacological profiles, particularly in relation to their tolerability, effects on safety parameters and patient acceptability. Olanzapine, risperidone and ziprasidone are associated with extrapyramidal symptoms (EPS) in a dose-dependent manner, whereas quetiapine has been shown to produce a significantly lower incidence of substantial EPS effects than haloperidol, and less EPS requiring treatment than risperidone. Similarly, unlike risperidone and haloperidol, quetiapine treatment has been associated with a significant reduction in serum prolactin levels, and has normalized raised prolactin levels after discontinuation of previous treatment. Weight gain is also one of the major unwanted adverse effects of treatment with many antipsychotic drugs but, in contrast, quetiapine has demonstrated a neutral or 'normalizing' effect on body weight. In comparison with other antipsychotics, quetiapine has been shown to possess a favourable safety profile, with no requirement for routine blood, thyroid, or liver monitoring during treatment. Overall, quetiapine therapy has produced high levels of patient satisfaction and compliance and this, coupled with its efficacy in reducing psychoses of various origins, has made it an attractive treatment option in both patients at increased risk of EPS, and the general population.