Switching to long-acting injectable antipsychotics: pharmacological considerations and practical approaches

Long-acting injectable antipsychotics (LAIs) are an effective, but potentially underutilized treatment option in schizophrenia and other severe mental illnesses. Prescribing information typically focuses on how to initiate treatment from the corresponding oral formulations. However, in clinical practice other scenarios, such as switching from other oral antipsychotics or other LAIs, occur frequently, requiring guidance.

Pharmacodynamic properties of antipsychotics and their relation to rebound symptoms. Pharmacokinetic properties of LAIs and their implications for switching approaches. Specific approaches to switching to LAIs.

The LAI landscape has evolved significantly in the last decade with more formulations available, longer dosing intervals, and extended indications. However, currently available LAIs have various shortcomings, e.g. short dosing intervals, need for oral supplementation, loading regimens, deep intramuscular injection and/or restricted indications. Recent improvements include a one-day initiation option for aripiprazole lauroxil, aripiprazole monohydrate once-monthly, risperidone in situ microparticles and subcutaneous risperidone. Future LAI developments should focus on longer dosing intervals, subcutaneous administration, expansion of LAIs beyond currently available antipsychotic agents and indications beyond schizophrenia and bipolar disorder. In the future, LAIs might become a first-line treatment after initial oral stabilization for chronic mental disorders with need for maintenance treatment and presence of significant non-adherence.