Can drug interaction be useful? Case report of a schizophrenic patient treated with paliperidone long-acting injection

Abstract

Introduction

Intramuscular paliperidone palmitate (PLAI) is a long-acting atypical anti-psychotic approved in Romania for the maintenance treatment of adults with schizophrenia.

Objectives

To determine the efficacy and tolerability of PLAI in a non-compliant patient with previously very low tolerability to oral anti-psychotics. The patient had been on risperidone long acting injection (RLAI) and had significant adverse events (i.e. tremor, akatisia) which persisted even when treated with the lowest dose of PLAI: 50 mg.

Aims

Since the efficacy of PLAI was good, and since a lower dose (than 50 mg of PLAI) is not available in Romania, we tried different ways to lower plasma concentration (PC) of the anti-psychotic because the patient presented clinically significant adverse effects (AE).

Methods

Initially the time between the injections was extended at maximum recommended (35 days), with a slight effect, then an off label treatment was associated in order to lower the PC of PLAI. We used 300 mg of carbamazepine long acting, that may lower the PC of PLAI up to 30%. For the evaluation of the efficacy and tolerability, we applied: the clinical evaluation, the positive and negative syndrome scale, the Barnes Akathisia rating scale, the Simpson-Angus Scale and the abnormal involuntary movement scale.

Results

After using the above mentioned, strategies, the one that had indeed good results on reducing AE, with no alteration of the psychic status of the patient, was the association of carbamazepine.

Conclusions

In clinical practice, some off label medication associations may be salutary!

Disclosure of interest

The authors have not supplied their declaration of competing interest.