Olanzapine: preclinical pharmacology and recent findings

Olanzapine possesses a broad pharmacological profile, interacting with a range of different neurotransmitter receptors. Although its affinity for muscarinic receptors is relatively greater than for dopamine receptors, on schedule-controlled behaviour olanzapine displays a profile resembling a dopamine antagonist. Likewise, in a test of cognitive function, olanzapine does not produce anticholinergic-like deficits. In drug discrimination assays, olanzapine substitutes for clozapine in clozapine-trained animals and clozapine generalises to olanzapine in olanzapine-trained animals. Olanzapine also reverses the behavioural deficits produced by inhibiting N-methyl-D-aspartate receptor glutamatergic transmission. This profile suggests that olanzapine will be effective against both positive and negative symptoms of schizophrenia while producing minimal extrapyramidal side-effects.