Consideration of long-acting injectable antipsychotics for polypharmacy regimen in the treatment of schizophrenia: put it on the table or not?
Chi-Un Pae 1, 2*, Changsu Han 3, Won-Myong Bahk 1, Soo-Jung Lee 1, Ashwin A. Patkar 4, Prakash S. Masand 5
1Department of Psychiatry, The Catholic University of Korea College of Medicine, Seoul, Republic of Korea, 2Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea, 3Department of Psychiatry, Korea University, College of Medicine, Seoul, Republic of Korea, 4Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA, 5Global Medical Education, New York, NY, USA
Received: August 26, 2020; Revised: November 11, 2020; Accepted: November 16, 2020; Published online: November 16, 2020.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Antipsychotic treatment is the mainstay in the biological treatment for schizophrenia. The similar efficacy of second generation antipsychotics have been consistently proposed, while their tolerability issues are substantially different due to differential pharmacological profile influencing on diverse neurotransmitter receptors. According to the numerous treatment guidelines, best-acceptable treatment approach is the antipsychotic monotherapy (APM) regardless of antipsychotic class and formulation types. However, a significant proportion of schizophrenia patients do not respond to APM and frequently relapse or recur in long-standing clinical course. Therefore antipsychotic polypharmacy (APP) using two or more antipsychotics for certain time have been also widely utilized in routine clinical practice over the world. However, APP has numerous pitfalls despite some clinical benefits in the treatment of schizophrenia since it usually causes increased total number and doses of antipsychotics which lead to unwanted adverse events as well as decrease of treatment adherence and persistence resulting in poor clinical outcomes. Recent introduction of long-acting injectable antipsychotics (LAIs) to the market has offered a chance for better medication adherence/persistence and also provided a simplification of treatment regime leading to more stabilized treatment for schizophrenia patients. When we cannot stay away from APP in the treatment of schizophrenia, clinicians need to find more proper APP regimens and thereby utilization of APP in efficient way should be a practical strategy to benefit schizophrenia patient in a real world treatment setting. With this regard, LAIs can be one of available APP regimen for treatment of schizophrenia in routine practice since their clinical utility and pharmacokinetic stability over oral APs have been well-elaborated today. However, when we have to commence LAIs as a part of APP with oral APs or other LAIs, every effort should be made before doing so whether or not validated and available treatment options or other clinical factors were not done or evaluated yet. Any treatment guidelines do not support APP regardless of the formulation of APP regimen or address two or more LAIs for treatment of schizophrenia till today.
Keywords: long-acting injectable antipsychotic, schizophrenia, monotherapy, polypharmacy, guideline, routine practice