Atypical antipsychotics and serotoninergic antidepressants in patients with epilepsy: Pharmacodynamic considerations

Purpose: To discuss the pharmacodynamic aspects of the administration of atypical antipsychotics (APs) and serotoninergic antidepressants (SSRIs) to patients with epilepsy. Methods: This article represents an over-view of all studies concerning the administration of APs and SSRIs to people with epilepsy. In particular, it deals with the relationship between neuroleptics (NLTs), APs, SSRIs, serotonin, and dopamine, with special focus on the possible epileptogenic role of psychoactive drugs. Results: NLTs may induce seizures by blocking D-2, H-2, and .1 receptors, or by sexual hormone activation or a pharmacologic kindling mechanism. The difference among APs in their ability to induce seizures is related mainly to the percentage of D-2-receptor occupancy and possibly also to their action on neurosteroids. Seizures occur at SSRIs therapeutic doses, with a 0.1-4% incidence. Coversely, in animal studies fluoxetine was claimed to exert an anticonvulsant action. Conclusions: The study of the pharmacodynamic aspects of the administration of APs and SSRIs to patients with epilepsy can help to evaluate the importance of some mechanisms of action of several psychoactive drugs in relation to their pro- or anticonvulsant activity.