Comparison of Side Effects Between 3-Monthly and 1-Monthly Paliperidone Palmitate Formulations in Patients With Schizophrenia - Clinical and Experimental

Sep 30, 2026

This study compares side effect profiles in real-world schizophrenia patients receiving paliperidone palmitate 1-month (PP1M) and those who switched from PP1M to the 3-month formulation (PP3M). Of 473 screened patients, 67 started PP1M and 43 provided evaluable within-patient data at both time points. Side effects were rated with the UKU Side Effect Rating Scale and symptom severity with established negative and positive symptom scales at four months after each dosing stage. Overall UKU burden increased with switching? The results showed broadly similar UKU profiles, stable side-effect frequencies, and a significant decrease in constipation after switching. Side effects were more prevalent with multiple antipsychotics than monotherapy.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

Abstract

Background

Material and Methods

Results

Conclusion

Introduction

Medication adherence and relapse

Role and concerns about long-acting injectables

Evidence gaps for PP3M safety

Human Psychopharmacology: Clinical and Experimental Comparison of Side Effects Between 3‐Monthly and 1‐ Monthly Paliperidone Palmitate Formulations in Patients With Schizophrenia Erkan Kuru1 | Ilker Ozdemir2 | Bengu Yucens3 | M. Hakan Türkçapar4 1Private Practice, Psychiatry, Ankara, Turkey | 2Department of Psychiatry, Bursa City Hospital, Bursa, Turkey | 3Department of Psychiatry, Faculty of Medicine, Pamukkale University, Denizli, Turkey | 4Department of Psychology, Social Sciences University of Ankara, Ankara, Turkey Correspondence: Erkan Kuru ([erkankuru83@gmail.com](erkankuru83@gmail.com); [erkan.kuru@rumeli.edu.tr](erkan.kuru@rumeli.edu.tr)) Received: 24 September 2025 | Revised: 15 December 2025 | Accepted: 23 December 2025 Keywords: antipsychotic agents | drug‐related side effects and adverse reactions | long‐acting injectable | paliperidone palmitate 3‐month | psychopharmacology | schizophrenia | treatment outcome ABSTRACT Background: The paliperidone palmitate 3‐month (PP3M) formulation offers an extended dosing interval compared to the 1‐ month (PP1M) formulation. However, data on the comparative side effect profiles of PP1M versus PP3M in real‐world settings remain limited. This study aimed to compare the side effect profiles in patients with schizophrenia receiving PP1M and those who switched from PP1M to PP3M. Material and Methods: Of 473 patients with schizophrenia screened, 132 received long‐acting injectable antipsychotics; 67 initiated PP1M, of whom 43 subsequently converted to PP3M and had evaluable data at both time points. The primary analysis used a within‐patient mirror‐image design (PP1M month‐4 vs PP3M month‐4) . Side effects were assessed using the UKU Side Effect Rating Scale, and symptom severity was evaluated with the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms, at 4 months after PP1M initiation and 4 months after PP3M switch. Results: UKU side‐effect profiles were broadly similar after conversion to PP3M, with no increase in the UKU total score. The most frequent side effects for both formulations were increased fatigability, hypokinesia, weight gain, and diminished sexual desire. The frequency of side effects remained mostly stable, with constipation showing a significant decrease after switching. Side effects were more prevalent in patients with schizophrenia using multiple antipsychotics compared to monotherapy. Conclusion: In this within‐patient cohort stabilized on PP1M, conversion to PP3M was not associated with an increase in overall UKU side‐effect burden. Selecting the appropriate dose before switching and preferring monotherapy may enhance treatment comfort. These results may help guide clinicians in selecting long‐acting injectable antipsychotics in practice. 1 | Introduction Effective management of schizophrenia typically involves consistent administration of antipsychotic medications: among individuals experiencing a first episode of schizophrenia, the risk of relapse reaches approximately 70% in those who do not comply with their medication regimen, whereas this rate drops to around 25% in patients who maintain adherence to their prescribed treatment (Patel and David 2005) . Despite this, nearly 50% of patients discontinue oral antipsychotic (OAP) therapy within the first year post‐discharge, and the proportion of those continuing treatment falls below 30% in the second year (Waddell and Taylor 2009; Zygmunt et al. 2002) . In this context, long‐acting injectable antipsychotics (LAIAs) have been shown to enhance medication adherence and help sustain long‐term therapeutic outcomes, with potential additional benefits This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2026 The Author(s) . Human Psychopharmacology: Clinical and Experimental published

FAQs

What is the main comparison in this study?

The study compares side effect profiles between patients maintained on paliperidone palmitate 1-month (PP1M) and those who switched from PP1M to paliperidone palmitate 3-month (PP3M).

How were side effects and symptom severity assessed?

Side effects were assessed using the UKU Side Effect Rating Scale, and symptom severity was evaluated using the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms.

Did switching from PP1M to PP3M increase overall side effects?

No. The UKU total score did not increase, and side-effect profiles were broadly similar after conversion to PP3M, with constipation decreasing significantly.

Sep 30, 2026

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