Quetiapine is an atypical antipsychotic drug. Quetiapine and its active plasma metabolite norquetiapine interact with multiple neurotransmitter receptors. Quetiapine and norquetiapine exhibit affinity for serotonin (5HT2) and dopamine D1 and D2 receptors in the brain. It is this combination of receptor antagonism with greater selectivity for 5HT2 than for D2 receptors that is believed to contribute to the clinical antipsychotic effects and low incidence of extrapyramidal side effects of Ketilept® Retard compared to typical antipsychotics.