Comparison of serum levels after intramuscular injections of 2% and 10% cis(Z)-flupentixol decanoate in Viscoleo to schizophrenic patients

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.

Clinically established biodegradable long acting injectables: An industry perspective

Long acting injectable formulations have been developed to sustain the action of drugs in the body over desired periods of time. These delivery platforms have been utilized for both systemic and local drug delivery applications. This review gives an overview of long acting injectable systems that are currently in clinical use. These products are categorized in three different groups: biodegradable polymeric systems, including microparticles and implants; micro and nanocrystal suspensions and oil-based formulations. Furthermore, the applications of these drug delivery platforms for the management of various chronic diseases are summarized. Finally, this review addresses industrial challenges regarding the development of long acting injectable formulations.

Flupenthixol decanoate (depot) for schizophrenia or other similar psychotic disorders

BACKGROUND

Long-acting depot injections of drugs such as flupenthixol decanoate are extensively used as a means of long-term maintenance treatment for schizophrenia.

OBJECTIVES

To evaluate the effects of flupenthixol decanoate in comparison with placebo, oral antipsychotics and other depot neuroleptic preparations for people with schizophrenia and other severe mental illnesses, in terms of clinical, social and economic outcomes.

SEARCH METHODS

We identified relevant trials by searching the Cochrane Schizophrenia Group Trials Register in March 2009 and then for this update version, a search was run in April 2013. The register is based on regular searches of CINAHL, EMBASE, MEDLINE and PsycINFO. References of all identified studies were inspected for further trials. We contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information.

SELECTION CRITERIA

All randomised controlled trials that focused on people with schizophrenia or other similar psychotic disorders where flupenthixol decanoate had been compared with placebo or other antipsychotic drugs were included. All clinically relevant outcomes were sought.

DATA COLLECTION AND ANALYSIS

Review authors independently selected studies, assessed trial quality and extracted data. For dichotomous data we estimated risk ratios (RR) with 95% confidence intervals (CI) using a fixed-effect model. Analysis was by intention-to-treat. We summated normal continuous data using mean difference (MD), and 95% CIs using a fixed-effect model. We presented scale data only for those tools that had attained prespecified levels of quality. Using Grading of Recommendations Assessment, Development and Evaluation (GRADE) we created 'Summary of findings tables and assessed risk of bias for included studies.

MAIN RESULTS

The review currently includes 15 randomised controlled trials with 626 participants. No trials compared flupenthixol decanoate with placebo.One small study compared flupenthixol decanoate with an oral antipsychotic (penfluridol). Only two outcomes were reported with this single study, and it demonstrated no clear differences between the two preparations as regards leaving the study early (n = 60, 1 RCT, RR 3.00, CI 0.33 to 27.23,very low quality evidence) and requiring anticholinergic medication (1 RCT, n = 60, RR 1.19, CI 0.77 to 1.83, very low quality evidence).Ten studies in total compared flupenthixol decanoate with other depot preparations, though not all studies reported on all outcomes of interest. There were no significant differences between depots for outcomes such as relapse at medium term (n = 221, 5 RCTs, RR 1.30, CI 0.87 to 1.93, low quality evidence), and no clinical improvement at short term (n = 36, 1 RCT, RR 0.67, CI 0.36 to 1.23, low quality evidence). There was no difference in numbers of participants leaving the study early at short/medium term (n = 161, 4 RCTs, RR 1.23, CI 0.76 to 1.99, low quality evidence) nor with numbers of people requiring anticholinergic medication at short/medium term (n = 102, 3 RCTs, RR 1.38, CI 0.75 to 2.25, low quality evidence).Three studies in total compared high doses (100 to 200 mg) of flupenthixol decanoate with the standard doses (˜40mg) per injection. Two trials found relapse at medium term (n = 18, 1 RCT, RR 1.00, CI 0.27 to 3.69, low quality evidence) to be similar between the groups. However people receiving a high dose had slightly more favourable medium term mental state results on the Brief Psychiatric Rating Scale (BPRS) (n = 18, 1 RCT, MD -10.44, CI -18.70 to -2.18, low quality evidence). There was also no significant difference in the use of anticholinergic medications to deal with side effects at short term (2 RCTs n = 47, RR 1.12, CI 0.83 to 1.52 very low quality evidence). One trial comparing a very low dose of flupenthixol decanoate (˜6 mg) with a low dose (˜9 mg) per injection reported no difference in relapse rates (n = 59, 1 RCT, RR 0.34, CI 0.10 to 1.15, low quality evidence).

AUTHORS' CONCLUSIONS

In the current state of evidence, there is nothing to choose between flupenthixol decanoate and other depot antipsychotics. From the data reported in clinical trials, it would be understandable to offer standard dose rather than the high dose depot flupenthixol as there is no difference in relapse. However, data reported are of low or very low quality and this review highlights the need for large, well-designed and reported randomised clinical trials to address the effects of flupenthixol decanoate.

Psychopharmacology and adverse effects of antipsychotic long-acting injections: a review

BACKGROUND

Depot antipsychotics are widely used in clinical practice. Long-acting formulations of second-generation antipsychotics are now being developed and introduced.

AIMS

To review the pharmacology, pharmacokinetics and adverse effect profiles of currently available antipsychotic long-acting injections (LAIs).

METHOD

The psychopharmacological properties of first- and second-generation antipsychotic LAIs are reviewed using data available up to October 2008.

RESULTS

First-generation antipsychotic (FGA) LAIs are associated with a high rate of acute and chronic movement disorders. Risperidone LAI is better tolerated in this respect, but is associated with hyperprolactinaemia and weight gain. Olanzapine LAI causes weight gain and other metabolic effects but appears not to be associated with an important incidence of movement disorders.

CONCLUSIONS

Dosing of LAIs is complicated by delayed release of drug, changes in plasma levels without change in dose, and by the lack of data establishing clear dose requirements. All LAIs offer the prospect of assured adherence (although patients may still default on treatment) but their use is complicated by adverse effects, complex pharmacokinetics and confusion over dose-response relationships.

Depot flupenthixol decanoate for schizophrenia or other similar psychotic disorders

BACKGROUND

Anti-psychotic drugs are the mainstay treatment for schizophrenia and similar psychotic disorders. Long-acting depot injections of drugs such as flupenthixol decanoate are extensively used as a means of long-term maintenance treatment.

OBJECTIVES

To evaluate the effects flupenthixol decanoate in comparison with placebo, oral antipsychotics and other depot neuroleptic preparations for people with schizophrenia and other severe mental illnesses, in terms of clinical, social and economic outcomes.

SEARCH STRATEGY

Relevant trials were identified by searching Biological Abstracts (1982-1998), Cochrane Library (Issue 2, 1998), Cochrane Schizophrenia Group's Register (December 1998), EMBASE (1980-1998), MEDLINE (1966-1998) and PsycLIT (1974-1998). The references of all identified trials were inspected for more studies and the first author of each included trial and relevant pharmaceutical companies were contacted.

SELECTION CRITERIA

All randomised controlled trials that focused on people with schizophrenia or other similar psychotic disorders where flupenthixol decanoate had been compared to placebo or other antipsychotic drugs. All clinically relevant outcomes were sought.

DATA COLLECTION AND ANALYSIS

Studies were reliably selected, quality rated and data extracted. For dichotomous data Peto odds ratios (OR) with 95% confidence intervals (CI) were estimated. Where possible, the number needed to treat statistic (NNT) was also calculated. Analysis was by intention-to-treat. Normal continuous data were summated using the weighted mean difference (WMD). Scale data were presented only for those tools that had attained pre-specified levels of quality.

MAIN RESULTS

No trials compared flupenthixol decanoate to placebo. One small study compared flupenthixol decanoate with an oral antipsychotic (penfluridol). There were no clear differences between the two preparations. When flupenthixol decanoate was compared to other depot preparations, there were no differences between depots for outcomes such as death, global impression, relapse (OR 1.16 CI 0.7-1.9) or leaving the study early (OR 1.00 CI 0.6-1.7). Two small studies suggest that flupenthixol decanoate is responsible for less movement disorders than other depot antipsychotic drugs (OR 0.23 CI 0.08-0.7, NNT 5). This finding did not hold for specific side effects, such as tremor (OR 1.2 CI 0.3-4) and tardive dyskinesia (OR 1.60 CI 0.4-6). Two trials comparing high doses of flupenthixol decanoate to the standard approximately 40mg per injection reported no significant difference for the outcome of relapse (OR 0.32 CI 0.09-1.2). One small (n=59) trial comparing a very low dose of flupenthixol decanoate ( approximately 6 mg/IM) to a very low dose approximately 9 mg per injection also reported no difference in relapse rates (OR 0.3 CI 0.1-1.1).

REVIEWER'S CONCLUSIONS

From the data reported in clinical trials, it would be understandable if those suffering from schizophrenia, who are willing to take flupenthixol decanoate, would request the standard dose rather than the high dose. In the current state of evidence, there is nothing to choose between flupenthixol decanoate and other depot antipsychotics. The choice of which depot to use must therefore be based on clinical judgement and the preferences of people with schizophrenia and their carers. Managers and policy makers should expect better data than the research community has provided thus far. This review highlighted the need for large, well-designed and reported randomised clinical trials to address the effects of flupenthixol decanoate, in particular when compared to oral antipsychotics. Future studies should also consider hospital and service outcomes, satisfaction with care and record economic data.

Low doses of cis-flupentixol attenuate motor performance

We evaluated the effects of cis-flupentixol on reinforced responding. The experimental subjects were rats and the reinforced response was a lever press. The procedure was a five-component multiple schedule that provided five different reinforcement rates. Cis-flupentixol produced dose-dependent decreases in reinforced responding. An equation, the matching law, was fitted to the results. One parameter of this equation represents the estimated response rate asymptote. Cis-flupentixol produced dose-dependent decreases in the asymptotes. A second parameter of the equation represents the rate of reinforcement that maintains a one-half asymptotic response rate. Cis-flupentixol did not appear to affect this measure. There is evidence that the response rate asymptote measures motor components of response rate and that the reinforcement parameter measures the efficacy of the reinforcement maintaining the response. According to these results, cis-flupentixol systematically affected the motor-component of reinforced responding-it slowed down lever pressing-without affecting the subject's sensitivity to the reinforcer maintaining the response. In contrast, other neuroleptics have decreased the subjects' sensitivity to reinforcement, according to the matching law measures.

Haloperidol decanoate and flupenthixol decanoate in schizophrenia. A long-term double-blind cross-over comparison

Thirty-two schizophrenic patients, previously treated with antipsychotics, were treated with haloperidol decanoate and flupenthixol decanoate in a double-blind cross-over study. The drugs were given for 24 weeks each at an individually adapted dose. The last three injections of either drug were given at fixed 4-week intervals. The mean dose over the two treatment periods changed from 131 mg (start) to 151 mg (week 24) in the haloperidol decanoate group and from 56 mg to 66 mg in the flupenthixol decanoate group, the inter-drug ratio being 2.3:1. During the first study period, the patients' condition remained rather stable with both drugs. After crossing-over, the symptoms were further reduced with haloperidol decanoate but increased with flupenthixol decanoate. Side effects of the two drugs were comparable and were generally few and mild. It was concluded that 4-week intramuscular administration of haloperidol decanoate provides appropriate control of schizophrenic symptoms, but that flupenthixol decanoate should be dosed at shorter intervals.

Clinical pharmacokinetics of the depot antipsychotics

The clinical pharmacokinetics of the 4 depot antipsychotics for which plasma level studies are available (i.e. fluphenazine enanthate and decanoate, haloperidol decanoate, clopenthixol decanoate and flupenthixol decanoate) are reviewed. The proper study of these agents has been handicapped until recently by the necessity of accurately measuring subnanomolar concentrations in plasma. Their kinetic properties, the relationship of plasma concentrations to clinical effects, and conversion from oral to injectable therapy are discussed. The depot antipsychotics are synthesised by esterification of the active drug to a long chain fatty acid and the resultant compound is then dissolved in a vegetable oil. The absorption rate constant is slower than the elimination rate constant and therefore, the depot antipsychotics exhibit 'flip-flop' kinetics where the time to steady-state is a function of the absorption rate, and the concentration at steady-state is a function of the elimination rate. Fluphenazine is available as both an enanthate and decanoate ester (both dissolved in sesame oil), although the decanoate is more commonly used clinically. The enanthate produces peak plasma concentrations on days 2 to 3 and declines with an apparent elimination half-life (i.e. the half-time of the apparent first-order decline of plasma concentrations) of 3.5 to 4 days after a single injection. The decanoate produces an early high peak which occurs during the first day and then declines with an apparent half-life ranging from 6.8 to 9.6 days following a single injection. After multiple injections of fluphenazine decanoate, however, the mean apparent half-life increases to 14.3 days, and the time to reach steady-state is 4 to 6 weeks. Withdrawal studies with fluphenazine decanoate suggest that relapsing patients have a more rapid plasma concentration decline than non-relapsing patients, and that the plasma concentrations do not decline smoothly but may exhibit 'lumps' due to residual release from previous injection sites or multicompartment redistribution. Cigarette smoking has been found to be associated with a 2.33-fold increase in the clearance of fluphenazine decanoate. In 3 different studies, fluphenazine has been proposed to have a therapeutic range from less than 0.15 to 0.5 ng/ml with an upper therapeutic range of 4.0 ng/ml. Plasma concentrations following the decanoate injection are generally lower than, but clinically equivalent to, those attained with the oral form of the drug. Haloperidol decanoate plasma concentrations peak on the seventh day following injection although, in some patients, this peak may occur on the first day.(ABSTRACT TRUNCATED AT 400 WORDS)

Serum concentrations of the isomers of clopenthixol and a metabolite in patients given cis(Z)-clopenthixol decanoate in viscoleo

Cis(Z)-clopenthixol decanoate in Viscoleo (Sordinol Depot, Cisordinol Depot, Clopixol Inj.) was given intramuscularly to nine schizophrenic patients with dosage intervals of 1 or 2 weeks. Serum concentrations of the two geometric isomers of clopenthixol and its N-dealkyl metabolite were recorded in two successive dosage intervals. Significant correlations were found for dose vs area under the serum concentration curve and vs serum concentrations measured on individual days. The last mentioned concentrations are good measures of the area under the serum concentration curve, which expresses the drug load of the patient. The serum concentration curves in two successive dosage intervals were very similar. Maximum serum concentration was seen 5-7 days after injection and the mean maximum/minimum fluctuation was 1.6 with the 2-week dosage interval. The finding of very low amounts of the trans(E)-isomers of clopenthixol and the N-dealkyl-metabolite shows that isomerization of the cis(Z)-compounds into the corresponding trans(E)-isomers does not take place within the organism.

Steady-state serum concentrations after cis (Z)-flupentixol decanoate in viscoleo

Serum concentrations of cis(Z)-flupentixol have been measured in patients on cis(Z)-flupentixol decanoate injections during successive dosage intervals of 2-4 weeks. The calculation of the fluctuation of the serum concentration in the dosage interval indicates that each individual patient should have his own dosage interval. For the 2-week group a significant correlation was found between weekly dose and preinjection concentration (r = 0.79) although an interindividual variability of X 4 was found. For this group the relative within-patient variation in the pre-injections concentration was calculated to be 9.6%, showing that a constant dosage regimen in the individual patient leads to an almost constant drug load.

Serum concentrations of cis(Z)-flupentixol and prolactin in chronic schizophrenic patients treated with flupentixol and cis(Z)-flupentixol decanoate

Nine chronic schizophrenic patients selected from three hospital departments were treated with flupentixol (orally and IV) and cis(Z)-flupentixol decanoate in Viscoleo (IM) in a three-phase pharmacokinetic study. Oral administration (single and repeated dosage) showed a relatively slow absorption with maximum serum concentration around 4 h after administration. Intravenous injection indicated multicompartment kinetics for cis(Z)-flupentixol. The biological half-lives calculated after the different doses were the same, indicating that the pharmacokinetics of cis(Z)-flupentixol does not differ between single and repeated administration and does not change when moderately higher doses are given. The bioavailability of orally administered cis(Z)-flupentixol was calculated to be about 40% with IV injection as reference. After IM administration maximum serum concentration was seen between 4 and 10 days in most patients. Calculation of a disappearance half-life gave very variable results, indicating that the release of the drug from the oil depot is not a monoexponential process. The intramuscular depot had a much lower bioavailability than IV injection, which means that steady state has not been obtained after 8 weeks of depot treatment. Serum prolactin concentrations were elevated during neuroleptic treatment, but no correlation was found between prolactin concentrations and the serum concentrations of cis(Z)-flupentixol. A correlation between the changes in clinical ratings and concentrations of cis(Z)-flupentixol or prolactin was not found.