Quetiapine: a Review of Its Safety in the Management of Schizophrenia

Quetiapine, a dibenzothiazepine derivative, is a atypical antipsychotic which has greater in vitro binding affinity for serotonin 5-HT2 receptors than for dopamine D2 receptors. Quetiapine effectively treats both the positive and the negative symptoms of schizophrenia and is also associated with an incidence of extrapyramidal symptoms no greater than placebo across the entire dose range. In addition, it does not cause persistent hyperprolactinaemia. Quetiapine is associated with high levels of patient acceptability and satisfaction, which may result from its combination of efficacy and relatively benign adverse effect profile. The drug is well tolerated and has a low propensity to cause adverse events both during acute and long term treatment in the adult populations. The adverse effect profile of quetiapine makes the drug advantageous for patient populations who are susceptible to the adverse effects of drugs. Indeed, preliminary data show quetiapine to be very well tolerated in the elderly. Overdoses of quetiapine of up to 20g have been reported; however, with appropriate management in an intensive care setting there have been no reported fatalities. Quetiapine is metabolised by the cytochrome P450 3A4 isoenzyme, and the dose may need to be adjusted if quetiapine is co-administered with drugs which affect the activity of this isoenzyme. Overall, quetiapine has a favourable risk-benefit profile that should make it a valuable first-line agent in the treatment of schizophrenia.