Advances in therapeutic drug monitoring of atypical antipsychotic drugs

The introduction in clinical practice of new antipsychotic drugs neurologically safer and with a broader spectrum of efficacy than "classical" neuroleptics has brought about significant improvement in the therapy of schizophrenic patients. These second-generation antipsychotics, usually called "atypical" antipsychotics, have several therapeutical features in common, such as their effectiveness against the negative symptoms of schizophrenia and the advantage of not causing severe extrapyramidal symptoms and hyperprolactinemia. The therapeutic drug monitoring of patients treated with atypical antipsychotics is, however, still advisable. In many cases it can avoid the onset of side and toxic effects due to high plasma levels of the drug caused by overdose or interactions with other drugs. Furthermore, monitoring can significantly improve the patient's compliance, thus leading to higher treatment efficacy. The pharmacological properties of the most widely used atypical antipsychotics (clozapine, olanzapine, risperidone and quetiapine) will be treated herein with particular attention paid to chemical-clinical correlations. The analytical methods suitable for the therapeutical drug monitoring of these drugs will also be discussed. Other recent atypical agents (ziprasidone, aripiprazole, iloperidone, sertindole and zotepine) will be described as well.