Seizure risk associated with psychotropic drugs: clinical and pharmacokinetic considerations

Psychiatric co-morbidity with epilepsy is common and often requires the com bined use of psychotropic and antiepileptic drugs (AEDs). Antidepressants a nd antipsychotic agents are believed to lower the threshold for new-onset s eizures and recurrent seizures in epilepsy patients. Factors that influence the risk for seizures during psychotropic drug therapy include the intrins ic convulsant potential of the drug, the drug dosage and plasma concentrati on, and patient-related risk factors for seizure occurrence. Available evid ence supports an increased risk for seizures associated with antidepressant and antipsychotic agents in overdose and during therapeutic use of high do ses of selected drugs. However, a clear differentiation in seizure risk bet ween most antidepressants and antipsychotics used at low to moderate therap eutic doses is not often possible. Limited studies of psychotropic drug use in patients with epilepsy demonstrate that these agents usually have a pos itive effect on the underlying psychiatric condition without an adverse eff ect on seizure occurrence. Pharmacokinetic interactions between AEDs and ps ychotropic drugs are common. Plasma concentration monitoring is often usefu l for minimizing the adverse consequences of these drug-drug interactions.