Evaluation of oral antipsychotic supplementation of select second-generation long-acting injectable antipsychotics in an acute-care psychiatric setting

Prescribing patterns of long-acting injectable antipsychotics in a community setting in South Africa

Background

Long-acting injectable antipsychotics (LAI – APs) improve adherence to antipsychotics and decrease functional decline in schizophrenia. Yet they are prescribed late, in patients with established functional decline. Although LAI – APs are widely prescribed in South Africa, there is a paucity of research regarding the prescription profile for LAI – APs.

Aim

This study aimed to describe prescribing practices for LAI – APs at psychiatric clinics.

Setting

Community psychiatric clinics in South Africa.

Methods

A retrospective review of the psychiatric files of all patients on LAI – APs attending the clinics over the study period was conducted. Sociodemographic, clinical and pharmacological information regarding the LAI – AP prescribed was extracted from the files.

Results

A total of 206 charts were examined. The mean age of the study population was 46 (SD ± 12) years. Significantly more patients were male (n = 154; 74.8%), single (n = 184, 89.3%) and unemployed (n = 115; 55.8%) (p < 0.001). Approximately half had a comorbid substance use disorder (47.6%). The most common indication for the prescription of a LAI – AP was non-adherence (66%). Only 9.7% of the patients were prescribed a LAI – AP alone. No significant socio-demographic or clinical characteristic was associated with this prescribing habit. A LAI – AP was prescribed in combination with an oral antipsychotic, mood stabiliser or antidepressant in 53.9%, 44.7% and 7.8% of patients, respectively.

Conclusion

Long-acting injectable antipsychotics were prescribed mainly following noncompliance with oral antipsychotics and may represent a missed opportunity to prevent functional decline. The high prevalence of LAI – AP polypharmacy has been highlighted.

Combination Therapy of Long-Acting Injectable Second-Generation Antipsychotics and Oral Antipsychotics: A Retrospective Chart Review and Prescribers' Attitude Survey

BACKGROUND

Although long-acting injectable antipsychotics (LAI-APs) have been considered as a monotherapeutic option in the maintenance treatment of schizophrenia, it has been recently reported that the combination therapy of LAI-APs and oral antipsychotics (OAPs) is common.

METHODS

We conducted a retrospective chart review to examine the situation of the combination therapy of LAI second-generation antipsychotics (LAI-SGAs) and OAPs, and a questionnaire survey to investigate prescribers' attitudes toward the combination therapy. We included patients who received any LAI-SGAs for 1 month or longer and classified them into monotherapy and combination therapy groups. We collected information on age, sex, primary psychiatric diagnosis, and concomitant psychotropic medications.

RESULTS

Of the 132 patients, 39 (29.5%) received the combination therapy of LAI-SGAs and OAPs. Long-acting injectable risperidone was significantly associated with receiving the combination therapy compared with LAI aripiprazole. Olanzapine was the most common OAP in combination with LAI-SGAs. Only 8 patients (20.5%) concurrently received the same type of OAPs as LAI-SGAs. More than 60% of the patients received OAP polypharmacy before the initiation of LAI-SGAs. The psychiatrists in charge prescribed LAI-SGAs mainly because of a concern about adherence, and OAPs mainly because of insufficient dose of LAI-SGAs, to patients in the combination therapy group. They estimated that adherence to OAPs in two thirds of the patients in the combination therapy group was 80% or higher.

CONCLUSIONS

The present study showed that the combination therapy of LAI-SGAs and OAPs is often conducted in real-world clinical practice. Considering the reason for the introduction of LAI-APs, clinicians should carefully monitor patients' adherence to OAPs concurrently used with LAI-APs.

Therapeutic Drug Monitoring of Long-Acting Injectable Antipsychotic Drugs

BACKGROUND

The use of therapeutic drug monitoring (TDM) to guide treatment with long-acting injectable (LAI) antipsychotics, which are increasingly prescribed, remains a matter of debate. The aim of this review was to provide a practical framework for the integration of TDM when switching from an oral formulation to the LAI counterpart, and in maintenance treatment.

METHODS

The authors critically reviewed 3 types of data: (1) positron emission tomography data evaluating dopamine (D2/D3) receptor occupancy related to antipsychotic concentrations in serum or plasma; D2/D3 receptors are embraced as target sites in the brain for antipsychotic efficacy and tolerability, (2) pharmacokinetic studies evaluating the switch from oral to LAI antipsychotics, and (3) pharmacokinetic data for LAI formulations. Based on these data, indications for TDM and therapeutic reference ranges were considered for LAI antipsychotics.

RESULTS

Antipsychotic concentrations in blood exhibited interindividual variability not only under oral but also under LAI formulations because these concentrations are affected by demographic characteristics such as age and sex, genetic peculiarities, and clinical variables, including comedications and comorbidities. Reported data combined with positron emission tomography evidence indicated a trend toward lower concentrations under LAI administration than under oral medications. However, the available evidence is insufficient to recommend LAI-specific therapeutic reference ranges.

CONCLUSIONS

Although TDM evidence for newer LAI formulations is limited, this review suggests the use of TDM when switching an antipsychotic from oral to its LAI formulation. The application of TDM practice is more accurate for dose selection than the use of dose equivalents as it accounts more precisely for individual characteristics.

The effects of concurrent oral paliperidone or risperidone use with paliperidone long-acting injection

Introduction

Dosing recommendations for paliperidone long-acting injectable antipsychotic (LAIA) do not include oral antipsychotic (OAP) overlap; however, OAPs are often given concurrently despite limited evidence describing both the risks and benefits of this practice.

Methods

A retrospective chart review was conducted in patients initiated on paliperidone palmitate (PP) during a psychiatric hospitalization to compare patients who received OAP overlap versus those who did not. The primary outcome is the proportion of patients who receive prescription claims for benztropine, a medication commonly prescribed for extrapyramidal symptoms, at the time of LAIA discontinuation and 6 months postdischarge. Secondary outcomes include prescription claims for beta blockers and diphenhydramine, number of psychiatric emergency visits and hospitalizations, length of stay of the index hospitalization, frequency of LAIA discontinuation and the time to LAIA discontinuation.

Results

There is a significant difference in the proportion of benztropine prescription claims in the OAP overlap group versus the no-overlap group at the time of LAIA discontinuation (30% vs 0%, P = .046) but not at 6 months postdischarge. There are also significant differences in the number of psychiatric emergency visits (0.7 vs 0.1, P = .02) and psychiatric hospitalizations (0.6 vs 0.1, P = .029) at the time of LAIA discontinuation. No other differences are observed in defined secondary outcomes.

Discussion

Patients who receive OAP overlap while receiving PP receive more benztropine and have more psychiatric emergency visits and hospitalizations than those treated without OAP. Larger studies with better control for confounding variables are needed to confirm these results.