The pursuit of linear dosage in pharmacy: reservoir-based drug delivery systems from macro to micro scale

INTRODUCTION

The pursuit of linear dosage in pharmacy is essential for achieving consistent therapeutic release and enhancing patient compliance. This review provides a comprehensive summary of zero-order drug delivery systems, with a particular focus on reservoir-based systems emanated from different microfabrication technologies.

AREAS COVERED

The consideration of recent advances in drug delivery systems is given to encompass the key areas including the importance of achieving a constant drug release rate for therapeutic applications. Detailed examination of reservoir-based systems, their design, mechanisms of action and materials used are highlighted. By addressing these areas, the discussion aims to provide a thorough understanding of most recent zero-order drug delivery systems, their performance advantages and methods of their manufacturing. To ensure the complete coverage of the explored research area, modern AI-assistant tools were used to find not only the most relevant, but also connected and similar articles.

EXPERT OPINION

Future developments in reservoir-based drug delivery systems are expected to significantly enhance therapeutic effectiveness and patient outcomes through the integration of innovative materials and technologies. The fabrication of intelligent drug delivery systems that utilize sensors and feedback mechanisms can enable real-time monitoring of drug release and patient reactions.

Abnormal Trajectory of Intracortical Myelination in Schizophrenia Implicates White Matter in Disease Pathophysiology and the Therapeutic Mechanism of Action of Antipsychotics

BACKGROUND

Postmortem and imaging studies provide converging evidence that the frontal lobe myelination trajectory is dysregulated in schizophrenia (SZ) and suggest that early in treatment, antipsychotic medications increase intracortical myelin (ICM). We used magnetic resonance imaging to examine whether the ICM trajectory in SZ is dysregulated and altered by antipsychotic treatment.

METHODS

We examined 93 subjects with SZ (64 men and 29 women) taking second-generation oral antipsychotics with medication exposures of 0-333 months in conjunction with 80 healthy control subjects (52 men and 28 women). Frontal lobe ICM volume was estimated using a novel dual contrast magnetic resonance imaging method that combines two images that track different tissue components.

RESULTS

When plotted against oral antipsychotic exposure duration, ICM of subjects with SZ was higher as a function of medication exposure during the first year of treatment but declined thereafter. In the age range examined, ICM of subjects with SZ was lower with increased age, while ICM of healthy control subjects was not.

CONCLUSIONS

In adults with SZ, the relationship between length of exposure to oral second-generation antipsychotics and ICM was positive during the first year of treatment but was negative after this initial period, consistent with suboptimal later adherence after initial adherence. This ICM trajectory resembles clinically observed antipsychotic response trajectory with high rates of remission in the first year followed by progressively lower response rates. The results support postmortem evidence that SZ pathophysiology involves ICM deficits and suggest that correcting these deficits may be an important mechanism of action for antipsychotics.

Efficacy, Safety, and Tolerability of RBP-7000 Once-Monthly Risperidone for the Treatment of Acute Schizophrenia: An 8-Week, Randomized, Double-Blind, Placebo-Controlled, Multicenter Phase 3 Study

RBP-7000 is a sustained-release formulation of risperidone for the treatment of schizophrenia, designed to be administered by once-monthly subcutaneous injection using the ATRIGEL delivery system. This study assessed the efficacy, safety, and tolerability of RBP-7000 compared with placebo in subjects with acute exacerbation of schizophrenia. Inpatients were randomly assigned to 8 weeks of double-blind treatment with subcutaneous 90 or 120 mg of RBP-7000 or placebo. Efficacy was evaluated using a mixed-model repeated-measures analysis of the change from baseline (the last nonmissing value before the first dose of RBP-7000 or placebo on day 1) to end of the study in Positive and Negative Syndrome Scale (PANSS) total score (primary efficacy measure) and Clinical Global Impression-Severity score (secondary efficacy measure). The least-squares means from the repeated-measures analysis for the change from baseline in the PANSS total scores for placebo was -9.219 (SE, 1.2162). RBP-7000 produced statistically and clinically significant differences in mean reductions from baseline in PANSS total scores (90-mg RBP-7000 compared with placebo, -6.148 [-9.982 to -2.314], P = 0.0004; 120-mg RBP-7000 compared with placebo, -7.237 [-11.045 to -3.429], P < 0.0001) and significantly improved Clinical Global Impression-Severity scores (90-mg RBP-7000 compared with placebo, -0.350 [-0.557 to -0.143], P = 0.0002; 120-mg RBP-7000 compared with placebo, -0.396 [-0.602 to -0.190], P < 0.0001). Both RBP-7000 dosages were generally well tolerated. The most frequently reported treatment-emergent adverse events in RBP-7000 groups compared with placebo were somnolence, weight gain, and akathisia. The overall incidence of extrapyramidal syndrome-related effects was low and similar across groups. RBP-7000 may provide a new, long-acting alternative treatment for use in adults with acute schizophrenia.

The role of long-acting injectable antipsychotics in schizophrenia: a critical appraisal

Despite their widespread use, long-acting injectable (LAI) antipsychotics (APs) are often regarded with some negativity because of the assumption of punishment, control and insufficient evolution towards psychosocial development of patients. However, LAI APs have proved effective in schizophrenia and other severe psychotic disorders because they assure stable blood levels, leading to a reduction of the risk of relapse. Therapeutic opportunities have also arisen after introduction of newer, second-generation LAI APs in recent years. Newer LAI APs are more readily dosed optimally, may be better tolerated and are better suited to integrated rehabilitation programmes. This review outlines the older and newer LAI APs available for the treatment of schizophrenia, with considerations of past and present pharmacological and therapeutic issues. Traditional, evidence-based approaches to systematic reviews and randomized clinical trials are of limited utility in this area so this paper's blending of experimental trials with observational research is particularly appropriate and effective.

A prospective, open-label study to evaluate symptomatic remission in schizophrenia with risperidone long-acting injectable in Korea

This study was designed to investigate long-term clinical outcomes of risperidone long-acting injectable (RLAI) in patients with schizophrenia or schizoaffective disorder. An open-label, 48-week, prospective study of RLAI treatment was carried out at 63 centers in South Korea. Initial and maintenance dosage of RLAI were adjusted according to clinical judgment. Efficacy was measured by the remission rate, continuation rate, and changes in the clinical measurements such as eight items of the Positive and Negative Symptom Scale (PANSS), the Clinical Global Impression - Severity, and the Schizophrenia Quality of Life Scale. In terms of the safety, Simpson-Angus rating Scale, adverse events (AEs), and BMI were investigated. Of the 522 patients who were enrolled, 472 patients who had been assessed on the eight items of PANSS at baseline and at least once during RLAI treatment were included in the intention-to-treat (ITT) population. The per-protocol (PP) population included 184 patients (39.0%), who completed all assessments during 48 weeks of the follow-up period. Total scores of eight items of PANSS, Clinical Global Impression - Severity, and Schizophrenia Quality of Life Scale were reduced significantly from baseline to endpoint in both ITT and PP populations. The mean dose (SD) of RLAI was 33.2 (7.6) mg. In the PP population, the number of patients who scored 1-3 on eight items of PANSS were 47 (25.5%) at baseline and 144 (78.3%) at 48 weeks. According to the remission defining as scores 1-3 on eight items of PANSS sustaining of at least 6 months' duration by Andreasen, the numbers of patients who achieved remission were 45 (24.5%) at 24 weeks and 120 (65.2%) at 48 weeks. A significant decrease in the mean score of Simpson-Angus rating Scale and a significant increase in BMI over time in last observation carried forward were observed, and patients who fulfilled the remission criteria during the study showed more weight gain than those who did not. During the study period, a total of 645 AEs were noted in 233 patients (49.3%) who were included in the ITT population. Sixty-nine serious AEs in 51 patients were reported, but all of them were not directly attributable to administration of RLAI. This prospective, open-label study showed improvements in symptom and AEs and a significant increase in BMI during 48 weeks of biweekly RLAI treatment. The rate of study completion was 39.0% and the remission rate among those who completed the study was 65.2%. None of the serious AEs were directly related to the administration of RLAI.

A review of paliperidone palmitate

Risperidone long-acting injection (RLAI) was the first second-generation antipsychotic available as a long-acting injection. Paliperidone (9-hydroxyrisperidone) is the active metabolite of risperidone, introduced initially as an extended release oral (ORal Osmotic System, OROS®, Alza Corporation) formulation (Invega®, Janssen). Paliperidone long-acting injection (PLAI) has now been developed as a suspension of paliperidone palmitate nanocrystals in an aqueous formulation (Invega Sustenna®, Xeplion®), administered monthly by intramuscular injection (deltoid or gluteal). Doses of PLAI can be expressed either in milligram equivalents (mg eq) of paliperidone palmitate or in milligrams of the active fraction of paliperidone. The recommended initiation regimen of 150 mg eq (234 mg) on day 1 and 100 mg eq (156 mg) on day 8 (both administered in the deltoid) achieves therapeutic blood levels rapidly and without the necessity of oral supplementation. No refrigeration or reconstitution prior to administration is required. PLAI has been shown in to be effective in controlling the acute symptoms of schizophrenia as well as delaying time to relapse. Safety and tolerability are comparable to RLAI with no new safety signals. Thus, PLAI may represent the rational development of RLAI with greater ease of use.

The cost effectiveness of long-acting/extended-release antipsychotics for the treatment of schizophrenia: a systematic review of economic evaluations

BACKGROUND

Antipsychotic medication is the mainstay of treatment in schizophrenia. Long-acting medication has potential advantages over daily medication in improving compliance and thus reducing hospitalization and relapse rates. The high acquisition and administration costs of such formulations raise the need for pharmacoeconomic evaluation.

OBJECTIVE

The aim of this article is to provide a comprehensive review of the available evidence on the cost effectiveness of long-acting/extended-release antipsychotic medication and critically appraise the strength of evidence reported in the studies from a methodological viewpoint.

METHODS

Relevant studies were identified by searching five electronic databases: PsycINFO, MEDLINE, EMBASE, the NHS Economic Evaluation Database and the Health Technology Assessment database (HTA). Search terms included, but were not limited to, 'long-acting injection', 'economic evaluation', 'cost-effectiveness' and 'cost-utility'. No limits were applied for publication dates and language. Full economic evaluations on long-acting/extended-release antipsychotics were eligible for inclusion. Observational studies and clinical trials were also checked for cost-effectiveness information. Conference abstracts and poster presentations on the cost effectiveness of long-acting antipsychotics were excluded. Thirty-two percent of identified studies met the selection criteria. Pertinent abstracts were reviewed independently by two reviewers. Relevant studies underwent data extraction by one reviewer and were checked by a second, with any discrepancies being clarified during consensus meetings. Eligible studies were assessed for methodological quality using the quality checklist for economic studies recommended by the NICE guideline on interventions in the treatment and management of schizophrenia.

RESULTS

After applying the selection criteria, the final sample consisted of 28 studies. The majority of studies demonstrated that risperidone long-acting injection, relative to oral or other long-acting injectable drugs, was associated with cost savings and additional clinical benefits and was the dominant strategy in terms of cost effectiveness. However, olanzapine in either oral or long-acting injectable formulation dominated risperidone long-acting injection in a Slovenian and a US study. Furthermore, in two UK studies, the use of long-acting risperidone increased the hospitalization days and overall healthcare costs, relative to other atypical or typical long-acting antipsychotics. Finally, paliperidone extended-release was the most cost-effective treatment compared with atypical oral or typical long-acting formulations. From a methodological viewpoint, most studies employed decision analytic models, presented results using average cost-effectiveness ratios and conducted comprehensive sensitivity analyses to test the robustness of the results.

LIMITATIONS

Variations in study methodologies restrict consistent and direct comparisons across countries. The exclusion of a large body of potentially relevant conference abstracts as well as some papers being unobtainable may have increased the likelihood of misrepresenting the overall cost effectiveness of long-acting antipsychotics. Finally, the review process was restricted to qualitative assessment rather than a quantitative synthesis of results, which could provide more robust conclusions.

CONCLUSIONS

Atypical long-acting (especially risperidone)/extended-release antipsychotic medication is likely to be a cost-effective, first-line strategy for managing schizophrenia, compared with long-acting haloperidol and other oral or depot formulations, irrespective of country-specific differences. However, inconsistencies in study methodologies and in the reporting of study findings suggest caution needs to be applied in interpreting these findings.

Chronic administration of risperidone in a rat model of schizophrenia: a behavioural, morphological and molecular study

In the present work we analyzed the effect of the chronic administration of risperidone (2mg/kg over 65 days) on behavioural, morphological and molecular aspects in an experimental model of schizophrenia obtained by bilateral injection of ibotenic acid into the ventral hippocampus of new-born rats. Our results show that during their adult lives the animals with hippocampal lesions exhibit different alterations, mainly at behavioural level and in the gene expression of dopamine D(2) and 5-HT(2A) receptors. However, at morphological level the study performed on the prefrontal cortex did not reveal any alterations in either the thickness or the number of cells immunoreactive for c-Fos, GFAP, CBP or PV. Overall, risperidone administration elicited a trend towards the recovery of the values previously altered by the hippocampal lesion, approaching the values seen in the animals without lesions. It may be concluded that the administration of risperidone in the schizophrenia model employed helps to improve the altered functions, with no significant negative effects.

A randomized, double-blind, placebo-controlled trial to assess prevention of mood episodes with risperidone long-acting injectable in patients with bipolar I disorder

The efficacy and safety of risperidone long-acting injectable (LAI) for preventing recurrence of mood episodes in patients with bipolar I disorder was evaluated in a randomized, placebo-controlled study. After a 12-week open-label period with risperidone LAI (n=560), patients who did not experience a recurrence entered an 18-month randomized, double-blind period with risperidone LAI (n=132) or placebo (n=135); a third treatment arm (n=131) was randomized to oral olanzapine (10 mg/day) for reference and exploratory comparisons. The primary efficacy endpoint was time to recurrence of any mood episode for risperidone LAI versus placebo in the double-blind period (Kaplan-Meier analysis). Additional efficacy endpoints included Young Mania Rating Scale, Montgomery-Asberg Depression Rating Scale and Clinical Global Impression. During the double-blind period, dosing was fixed at patients' final open-label dose (25 mg, 66% of patients; 37.5 mg, 31%; 50 mg, 4%). The primary outcome demonstrated a median time to mood episode recurrence of 198 day in the placebo arm, whereas the median was not reached in the risperidone LAI arm (p=0.057). Time to recurrence of any mood episode was significantly longer with risperidone LAI versus placebo (log-rank test stratified by region only, p=0.031); the difference was significant for time to recurrence of elevated mood episodes (p=0.005) but not depressive episodes (p=0.655). Significant improvement of manic symptoms and global condition versus placebo were observed for risperidone LAI, with no evidence of worsening of depression. In conclusion, risperidone LAI significantly delayed time to recurrence of elevated mood episodes, with a safety profile consistent with previous studies.

Impact on intracortical myelination trajectory of long acting injection versus oral risperidone in first-episode schizophrenia

CONTEXT

Imaging and post-mortem studies suggest that frontal lobe intracortical myelination is dysregulated in schizophrenia (SZ). Prior MRI studies suggested that early in the treatment of SZ, antipsychotic medications initially increase frontal lobe intracortical myelin (ICM) volume, which subsequently declines prematurely in chronic stages of the disease. Insofar as the trajectory of ICM decline in chronic SZ is due to medication non-adherence or pharmacokinetics, it may be modifiable by long acting injection (LAI) formulations.

OBJECTIVES

Assess the effect of risperidone formulation on the ICM trajectory during a six-month randomized trial of LAI (RLAI) versus oral (RisO) in first-episode SZ subjects.

DESIGN

Two groups of SZ subjects (RLAI, N=9; and RisO, N=13) matched on pre-randomization oral medication exposure were prospectively examined at baseline and 6 months later, along with 12 healthy controls (HCs). Frontal lobe ICM volume was assessed using inversion recovery (IR) and proton density (PD) MRI images. Medication adherence was tracked.

MAIN OUTCOME MEASURE

ICM volume change scores were adjusted for the change in the HCs.

RESULTS

ICM volume increased significantly (p=.005) in RLAI and non-significantly (p=.39) in the RisO groups compared with that of the healthy controls. A differential between-group treatment effect was at a trend level (p=.093). SZ subjects receiving RLAI had better medication adherence and more ICM increases (chi-square p<.05).

CONCLUSIONS

The results suggest that RLAI may promote ICM development in first-episode SZ patients. Better adherence and/or pharmacokinetics provided by LAI may modify the ICM trajectory. In vivo MRI myelination measures can help clarify pharmacotherapeutic mechanisms of action.

Neuroglialpharmacology: myelination as a shared mechanism of action of psychotropic treatments

Current psychiatric diagnostic schema segregate symptom clusters into discrete entities, however, large proportions of patients suffer from comorbid conditions that fit neither diagnostic nor therapeutic schema. Similarly, psychotropic treatments ranging from lithium and antipsychotics to serotonin reuptake inhibitors (SSRIs) and acetylcholinesterase inhibitors have been shown to be efficacious in a wide spectrum of psychiatric disorders ranging from autism, schizophrenia (SZ), depression, and bipolar disorder (BD) to Alzheimer's disease (AD). This apparent lack of specificity suggests that psychiatric symptoms as well as treatments may share aspects of pathophysiology and mechanisms of action that defy current symptom-based diagnostic and neuron-based therapeutic schema. A myelin-centered model of human brain function can help integrate these incongruities and provide novel insights into disease etiologies and treatment mechanisms. Available data are integrated herein to suggest that widely used psychotropic treatments ranging from antipsychotics and antidepressants to lithium and electroconvulsive therapy share complex signaling pathways such as Akt and glycogen synthase kinase-3 (GSK3) that affect myelination, its plasticity, and repair. These signaling pathways respond to neurotransmitters, neurotrophins, hormones, and nutrition, underlie intricate neuroglial communications, and may substantially contribute to the mechanisms of action and wide spectra of efficacy of current therapeutics by promoting myelination. Imaging and genetic technologies make it possible to safely and non-invasively test these hypotheses directly in humans and can help guide clinical trial efforts designed to correct myelination abnormalities. Such efforts may provide insights into novel avenues for treatment and prevention of some of the most prevalent and devastating human diseases.

The threshold rate of oral atypical anti-psychotic adherence at which paliperidone palmitate is cost saving

OBJECTIVE

To identify, estimate, and compare 'real world' costs and outcomes associated with paliperidone palmitate compared with branded oral atypical anti-psychotics, and to estimate the threshold rate of oral atypical adherence at which paliperidone palmitate is cost saving.

METHODS

Decision analytic modeling techniques developed by Glazer and Ereshefsky have previously been used to estimate the cost-effectiveness of depot haloperidol, LAI risperidone, and, more recently, LAI olanzapine. This study used those same techniques, along with updated comparative published clinical data, to evaluate paliperidone palmitate. Adherence rates were based on strict Medication Event Monitoring System (MEMS) criteria. The evaluation was conducted from the perspective of US healthcare payers.

RESULTS

Paliperidone palmitate patients had fewer mean annual days of relapse (8.7 days; 6.0 requiring hospitalization, 2.7 not requiring hospitalization vs 17.8 days; 12.4 requiring hospitalization, 5.4 not requiring hospitalization), and lower annual total cost ($20,995) compared to oral atypicals (mean $22,481). Because paliperidone palmitate was both more effective and less costly, it is considered economically dominant. Paliperidone palmitate saved costs when the rate of adherence of oral atypical anti-psychotics was below 44.9% using strict MEMS criteria. Sensitivity analyses showed results were robust to changes in parameter values. For patients receiving 156 mg paliperidone palmitate, the annual incremental cost was $1216 per patient (ICER = $191 per day of relapse averted). Inclusion of generic risperidone (market share 18.6%) also resulted in net incremental cost for paliperidone palmitate ($120; ICER = $13). Limitations of this evaluation include use of simplifying assumptions, data from multiple sources, and generalizability of results.

CONCLUSIONS

Although uptake of LAIs in the US has not been as rapid as elsewhere, many thought leaders emphasize their importance in optimizing outcomes in patients with adherence problems. The findings of this analysis support the cost-effectiveness of paliperidone palmitate in these patients.

Treatment adherence with early prescription of long-acting injectable antipsychotics in recent-onset schizophrenia

Although response to treatment for the first episode of schizophrenia is generally favourable, nonadherence with the treatment is the first cause of relapse and rehospitalisation within the next few years. Long-acting injectable antipsychotics (LAIAs) combine the advantages of the newer antipsychotics and the long-acting formulation. The evaluation concerns 25 schizophrenic patients hospitalised for the first time, treated with risperidone long-acting injectable (RLAI) associated with reintegration methods, and followed up for at least 18 months. Clinical observation was completed using Clinical Global Impression (CGI) scale and Global Assessment of Functioning (GAF). Clinical improvement was coupled with a good reintegration rate, very few relapse, or rehospitalisation. Bimonthly injection combined with psychosocial methods improved interactive followup, and therefore patients' compliance with the treatment. Treating with LAIA as early as possible, from the first episode if possible, can reduce relapse, number and duration of rehospitalisation, and cognitive symptoms and improve the quality of life and prognosis.

Assessment of effectiveness measures in patients with schizophrenia initiated on risperidone long-acting therapy: the SOURCE study results

BACKGROUND

To evaluate effectiveness outcomes in a real-world setting in patients with schizophrenia initiating risperidone long-acting therapy (RLAT).

METHODS

This was a 24-month, multicenter, prospective, longitudinal, observational study in patients with schizophrenia who were initiated on RLAT. Physicians could change treatment during the study as clinically warranted. Data were collected at baseline and subsequently every 3 months up to 24 months. Effectiveness outcomes included changes in illness severity as measured by Clinical Global Impression-Severity (CGI-S) scale; functional scores as measured by Personal and Social Performance (PSP) scale, Global Assessment of Functioning (GAF), and Strauss-Carpenter Levels of Functioning (LOF); and health status (Medical Outcomes Survey Short Form-36 [SF-36]). Life-table methodology was used to estimate the cumulative probability of relapse over time. Adverse events were evaluated for safety.

RESULTS

532 patients were enrolled in the study; 209 (39.3%) completed the 24-month study and 305 (57.3%) had at least 12 months of follow-up data. The mean (SD) age of patients was 42.3 (12.8) years. Most patients were male (66.4%) and either Caucasian (60.3%) or African American (23.7%). All changes in CGI-S from baseline at each subsequent 3-month follow-up visit were statistically significant (p < .0001), indicating improvement in disease severity. Improvements were also noted for the PSP, GAF, and total LOF, indicating improvement in daily functioning and health outcome.

CONCLUSIONS

Patients with schizophrenia who were initiated on RLAT demonstrated improvements in measures of effectiveness within 3 months, which persisted over 24 months.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00246194.

Long acting injection versus oral risperidone in first-episode schizophrenia: differential impact on white matter myelination trajectory

CONTEXT

Imaging and post-mortem studies provide converging evidence that subjects with schizophrenia (SZ) have a dysregulated trajectory of frontal lobe myelination. Prior MRI studies suggested that early in treatment of SZ, antipsychotic medications initially increase frontal lobe white matter (WM) volume, which subsequently declines prematurely in chronic stages of the disease. Insofar as the trajectory of WM decline associated with chronic disease may be due to medication non-adherence, it may be modifiable by long acting injection (LAI) formulations.

OBJECTIVES

Examine the impact of antipsychotic formulation on the myelination trajectory during a randomized six-month trial of LAI risperidone (RLAI) versus oral risperidone (RisO) in first-episode SZ subjects.

DESIGN

Two groups of SZ subjects (RLAI, N=11; and RisO, N=13) that were matched in pre-randomization oral medication exposure and 14 healthy controls (HCs) were prospectively examined. Frontal lobe WM volume was estimated using inversion recovery (IR) MRI images. A brief neuropsychological battery that focused on reaction times was performed at the end of the study.

MAIN OUTCOME MEASURE

WM volume change scores.

RESULTS

WM volume remained stable in the RLAI and decreased significantly in the RisO groups resulting in a significant differential treatment effect, while the HC had a WM change intermediate and not significantly different from the two SZ groups. WM increase was associated with faster reaction times in tests involving frontal lobe function.

CONCLUSIONS

The results suggest that RLAI may improve the trajectory of myelination in first-episode patients and have a beneficial impact on cognitive performance. Better adherence provided by LAI may underlie the modified trajectory of myelin development. In vivo MRI biomarkers of myelination can help clarify mechanisms of action of treatment interventions.

Long-acting injectable antipsychotics in the treatment of schizophrenia: their role in relapse prevention

IMPORTANCE OF THE FIELD

Antipsychotic medications are the cornerstone of treatment in schizophrenia, and a large body of data confirms the value of ongoing and continuous antipsychotic pharmacotherapy in controlling symptoms and preventing relapse. However, nonadherence with antipsychotic treatment is a significant issue, with estimates as high as 90%.

AREAS COVERED IN THIS REVIEW

This review focuses on long-acting injectable (LAI) antipsychotics and their role in the treatment of schizophrenia. The existing literature, with an emphasis on clinical evidence, is assessed. This includes both reviews and specific trials that examine LAIs and compare them with oral agents, with measures ranging from relapse and rehospitalization to adherence. Both advantages and limitations (e.g., challenges in terms of dose titration and time to steady state) are examined.

WHAT THE READER WILL GAIN

This overview serves as an update for clinicians wishing to understand LAIs better, including the newer second-generation antipsychotics (SGAs) with this formulation available, and their potential role in the long-term treatment of individuals with schizophrenia.

TAKE HOME MESSAGE

Despite identified advantages, LAIs are not used as widely as might be expected. It would seem that clinicians are at least partly responsible for this, influenced by our own misperceptions (e.g., that LAIs are not acceptable to patients) and, perhaps, misinformation (e.g., increased side effect risk). As clinicians, we may well be shortchanging LAIs if we position them as a treatment of last resort for the multi-episode, nonadherent, 'revolving door' patient, especially given recent evidence underscoring their potential benefits in first-episode patients. The search for new and more effective antipsychotics will continue, but we are reminded that suboptimal outcomes may have as much to do with nonadherence as inadequate treatments. Evidence has established that LAI antipsychotics demonstrate distinct benefits in this regard, and we would be remiss if we did not exploit this already available strategy. As well as additional research, we need to rethink how we position these agents in our treatment algorithms if we are to maximize their potential.

Patient perspectives on use of long-acting antipsychotics in bipolar disorder: focus on risperidone injection

In the last few years, oral second-generation antipsychotics have demonstrated mood-stabilizing properties and are now widely used in the treatment of bipolar disorder. Unfortunately, treatment of this chronic and complex illness is hampered with poor adherence on the part of patients. Long-acting injectable formulations of second-generation antipsychotics could combine the effect of oral second-generation antipsychotics in patients with bipolar disorder and the benefits of depot formulation with the assurance of steady medication delivery and thereby improve adherence. In this context, the efficacy and tolerance of risperidone long-acting injection (RLAI) for maintenance treatment in patients with bipolar disorder is assessed. The relevant studies found RLAI to be effective in preventive treatment of manic but not depressive recurrences in bipolar patients, with good tolerance. RLAI appeared to be particularly suitable for patients with known poor adherence to treatment or severe bipolar disorder (such as patients who relapse frequently). Lastly, if RLAI, unlike the first-generation antipsychotics, does not induce depressive symptoms, the different studies do not enable us to consider its use in monotherapy in the preventive treatment of patients with depressive polarity. Long-acting second-generation antipsychotics in bipolar patients are therefore associated with long-term benefits, but their use in clinical practice needs to be improved.

Risperidone long-acting injection as monotherapy and adjunctive therapy in the maintenance treatment of bipolar I disorder

IMPORTANCE OF THE FIELD

It is very rare for patients with bipolar disorder to have a single episode of mania or depression over a lifetime and the vast majority of these individuals need long-term prophylactic/maintenance treatment. However, treatment nonadherence is a major issue for close to half of subjects with bipolar disorder who are prescribed medications. Risperidone long-acting injection (LAI) has proven efficacious for the maintenance phase of bipolar disorder and may mitigate the problem of nonadherence in the substantial group of patients for whom this is a significant concern.

AREAS COVERED IN THIS REVIEW

This paper comprises a review and commentary regarding the use of risperidone LAI in bipolar disorder.

WHAT THE READER WILL GAIN

The reader will gain an understanding regarding the risks and benefits of risperidone LAI in bipolar disorder. We review the available evidence and discuss the strengths and weaknesses of published studies, providing an opinion about the clinical usefulness of risperidone LAI as well as suggestions for future research.

TAKE HOME MESSAGE

The use of risperidone LAI, through improved adherence, has the potential to ameliorate the course of bipolar disorder.