A review of pharmacokinetic and pharmacodynamic interactions with antipsychotics

INTRODUCTION: Antipsychotics are widely used and often in combination with other drugs, thereby frequently subjected to drug-drug interactions. This review will provide a summary of potential pharmacokinetic (PK) and pharmacodynamic (PD) drug interactions associated with antipsychotic drugs. METHODS: A literature search was conducted for clinically significant drug interactions with antipsychotics. RESULTS: Most common PK drug interactions take place via the cytochrome P450 (CYP) system. PK profiles of first generation antipsychotics are inadequately studied; nevertheless most common drug interactions involve changes to their metabolic processes. Interactions with second generation antipsychotics are somewhat well-established, documented, and give some guidance for therapeutic treatment interventions. PD interactions occurring at the receptor level result in additive, synergistic, or antagonistic effects. DISCUSSION: This review summarizes a collection of relevant literature of significant PK and PD interactions occurring with antipsychotics. The involvement of multiple CYP enzymes makes it more difficult to predict the extent of the interaction and clinicians should take into consideration the timeline when evaluating potential interactions.