Oral depot antipsychotic drugs: time for a paradigm shift?

Switching to long-acting injectable antipsychotics: pharmacological considerations and practical approaches

INTRODUCTION

Long-acting injectable antipsychotics (LAIs) are an effective, but potentially underutilized treatment option in schizophrenia and other severe mental illnesses. Prescribing information typically focuses on how to initiate treatment from the corresponding oral formulations. However, in clinical practice other scenarios, such as switching from other oral antipsychotics or other LAIs, occur frequently, requiring guidance.

AREAS COVERED

Pharmacodynamic properties of antipsychotics and their relation to rebound symptoms. Pharmacokinetic properties of LAIs and their implications for switching approaches. Specific approaches to switching to LAIs.

EXPERT OPINION

The LAI landscape has evolved significantly in the last decade with more formulations available, longer dosing intervals, and extended indications. However, currently available LAIs have various shortcomings, e.g. short dosing intervals, need for oral supplementation, loading regimens, deep intramuscular injection and/or restricted indications. Recent improvements include a one-day initiation option for aripiprazole lauroxil, aripiprazole monohydrate once-monthly, risperidone in situ microparticles and subcutaneous risperidone. Future LAI developments should focus on longer dosing intervals, subcutaneous administration, expansion of LAIs beyond currently available antipsychotic agents and indications beyond schizophrenia and bipolar disorder. In the future, LAIs might become a first-line treatment after initial oral stabilization for chronic mental disorders with need for maintenance treatment and presence of significant non-adherence.

Weekly Supervised Administration of Oral Antipsychotics: An Alternative to Long-Acting Injections?

Maintenance of response in schizophrenia is largely dependent on compliance with antipsychotic treatment. When people with schizophrenia are responsible for their own treatment, partial or non-adherence is common and usually results in relapse. Assured compliance with antipsychotic treatment is possible when long-acting injectable antipsychotics are given by healthcare staff, but some patients may not consent to treatment for a variety of reasons. An alternative to long-acting injections is the use of supervised oral administration of long-acting antipsychotics. This method assures compliance with prescribed regimens without the need for injections. To be suitable for once-weekly administration as an oral formulation, an antipsychotic needs to have a sufficiently long duration of action and to be well tolerated in high doses. There is evidence that weekly oral administration of either pimozide or penfluridol is effective and well tolerated in the treatment of schizophrenia. Other drugs potentially suitable for once-weekly oral administration include aripiprazole, brexpiprazole and cariprazine.

Evaluation of the effectiveness and acceptability of the long-acting oral antipsychotic penfluridol: Illustrative case series

AIM

In this study, we sought to determine clinical outcomes at 1 year for patients prescribed penfluridol in an inner London National Health Service Trust. Using noninterventional data, we describe the use, effectiveness and safety of this treatment modality.

RESULTS

We retrospectively followed up 17 patients prescribed penfluridol as part of routine clinical practice. All patients took penfluridol once weekly. Of these patients, 12 (70.6%) were considered treatment resistant. The average duration of illness for this cohort was 10 years (SD = 6.7). At 1 year, nine (53%) patients remained on treatment. Median survival time was not reached at 1-year follow-up; mean time on penfluridol was 251 days (95% confidence interval (CI), 184-318). The mean number of admissions to hospital in the year following penfluridol initiation was 0.6 compared with 0.8, 1 year before initiation (p = 0.465). The median number of bed days 1 year before penfluridol initiation was 24, whereas in the year following penfluridol initiation, it was 0 (p = 0.514).

CLINICAL IMPLICATIONS

Although penfluridol is unlicensed in the United Kingdom, limited data suggest that this long-acting oral therapy has the potential to be used safely and effectively for the treatment of psychotic disorders. However, more data are required to establish the place of penfluridol and other potential long-acting oral antipsychotic formulations in the treatment of psychotic disorders.

New approaches to antipsychotic medication adherence - safety, tolerability and acceptability

INTRODUCTION

Antipsychotic pharmacotherapy is considered a first-line treatment in schizophrenia-related disorders and is associated with favorable prognosis and lower mortality rates. However, low adherence rates present a major clinical challenge. In this paper, we will review contemporary approaches to improve adherence to antipsychotic treatment, considering their mechanism of action, safety, tolerability and acceptability.

AREAS COVERED

Novel pharmacological delivery methods included different routes of administration of registered medications (such as intramuscular clozapine preparation and transdermal asenapine), modifications of existing compounds (such as 3-monthly injectable formulation of paliperidone palmitate), and increased interest in oral long-acting medication formulations (such as with penfluridol). In addition, we reviewed innovative technology to monitor adherence, based on the use of electronic digital medicine systems and ingestible sensors.

EXPERT OPINION

All of these diverse approaches were clinically relevant in enhancing treatment adherence and found to be safe and tolerable. The place of each approach is predicated on a personalized approach in each patient, and future research could usefully use large comparative studies to establish robust treatment guidelines. The implementation of new and varied approaches to antipsychotic treatment adherence is welcomed and have the potential to make a significant impact on morbidity in this often difficult-to-treat population.