Pharmacokinetics of antipsychotic drugs in man

Safety and effectiveness of rapid-acting intra-muscular olanzapine for agitation associated with schizophrenia - Japan postmarketing surveillance study

OBJECTIVE

The objective of this study was to evaluate the safety and effectiveness of rapid-acting intramuscular (IM) olanzapine in the treatment of acute agitation associated with schizophrenia in real-world clinical settings in Japan.

METHODS

In this multicenter, postmarketing surveillance (PMS) study, patients with acute agitation associated with schizophrenia were treated with IM olanzapine daily in a daily clinical setting. The observational period ranged from 1 to 7 days, including the day of initial administration. Safety was assessed by reporting treatment-emergent adverse events (TEAEs) and adverse drug reactions (ADRs). The Positive and Negative Syndrome Scale - Excited Component (PANSS-EC) score was used to evaluate effectiveness at baseline and at 2 hours (after each administration), 2 days, and 3 days (end of the observational period) from the last administration of the IM olanzapine injection.

RESULTS

The safety analysis set included 999 patients, and the initial dose of 10 mg was administered to 955 patients. TEAEs were reported in 28 patients (36 events), the most common of which were dyslalia (5 patients), akathisia and somno lence (4 patients each), hepatic function abnormal (3 patients), and constipation and dehydration (2 patients each). One serious adverse event of akathisia occurred during the observation period. The PANSS-EC score (mean ± standard deviation) was 23.3±6.4 (n=625) at baseline, 16.9±7.0 (n=522) at 2 hours after initial injection, and 14.9±6.5 (n=650) at the last observation carried forward.

CONCLUSION

The results of this Japanese PMS study demonstrated that IM olanzapine is safe and has a favorable effectiveness profile in the treatment of schizophrenia patients with acute agitation.

Effectiveness and safety of oral olanzapine treatment transitioned from rapid-acting intramuscular olanzapine for agitation associated with schizophrenia

OBJECTIVE

To assess the effectiveness and safety of oral olanzapine treatment transitioned from rapid-acting intramuscular olanzapine (RAIM) in patients with acute agitation associated with schizophrenia in a real-world clinical setting.

METHODS

The postmarketing surveillance study with a 3-day observational period after the last RAIM administration was conducted (original study). Following this, an extended study was added for patients who received oral olanzapine after RAIM administration during the original study period, in order to additionally observe them for 7 days after initial RAIM administration. Effectiveness and safety from initial RAIM administration were evaluated using the Positive and Negative Syndrome Scale-Excited Component score and treatment-emergent adverse events (TEAEs), respectively.

RESULTS

The effectiveness and safety analysis set included a total of 521 and 522 patients, respectively. A majority of patients received 10 mg of RAIM (475/522 patients, 91.0%). The mean ± SD total Positive and Negative Syndrome Scale-Excited Component score was 23.6±6.2 (n=318) at baseline (before initial RAIM administration), 17.4±6.8 (n=280) at 2 hours after initial administration, 16.2±6.8 (n=246) 2 days after final administration, 14.9±6.2 (n=248) 3 days after final administration, 13.8±5.9 (n=242) 4 days after final administration, 13.2±5.8 (n=221) 7 days after initial administration, and 13.4±6.2 (n=351) at final observation (with the last observation carried forward approach), showing that reduction in agitation seen with RAIM was sustained with oral dose of olanzapine. The most common TEAEs were dyslalia and somnolence (each event occurred in four patients), and abnormal hepatic function and constipation (occurred in three patients). One serious adverse event of sudden cardiac death occurred after transitioned to oral olanzapine with many other antipsychotic drugs.

CONCLUSION

In the treatment of acute agitation associated with schizophrenia, RAIM could be generally transitioned to oral olanzapine without exacerbating adverse events or losing treatment effect.

A randomized, double-blind, placebo-controlled study of rapid-acting intramuscular olanzapine in Japanese patients for schizophrenia with acute agitation

BACKGROUND

Olanzapine rapid-acting intramuscular (IM) injection is an atypical antipsychotic drug already used overseas and recently approved in Japan. The objective of this study was to confirm the efficacy of rapid-acting IM olanzapine 10 mg was greater than IM placebo in patients with exacerbation of schizophrenia with acute psychotic agitation by comparing changes from baseline to 2 hours after the first IM injection, as measured by the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) total score.

METHODS

We conducted a placebo-controlled, randomized, double-blind, parallel-group study in Japanese patients diagnosed with schizophrenia according to the diagnostic criteria specified in the DSM-IV-TR. Patients were randomized to 2 treatment groups: IM olanzapine (10 mg) or IM placebo. The primary efficacy outcome was the change in PANSS-EC from baseline to 2 hours after the first IM injection. Treatment groups were compared with an analysis of variance model which included treatment and site as factors. During the 24-hour treatment period, safety was assessed by clinical examination and laboratory investigations, electrocardiograms, extrapyramidal symptoms scales, and recording spontaneously reported adverse events.

RESULTS

Of the 91 randomized patients, 90 patients (45 IM olanzapine-group; 45 IM placebo-group) were in the full analysis set. The mean change of PANSS-EC total score from baseline to 2 hours after the first IM injection (mean±standard deviation) was -9.2±4.5 for the IM olanzapine group and -2.8±5.6 for the IM placebo group. The difference between treatment groups was statistically significant (p<.001). There were no deaths, serious adverse events, treatment-emergent adverse events (TEAEs) leading to discontinuation, severe TEAEs, or instances of oversedation in this study. There were no statistically significant differences between treatment groups in the proportion of patients with potentially clinically significant changes in laboratory tests, vital signs (blood pressure and pulse rate), electrocardiograms, and treatment-emergent extrapyramidal symptoms.

CONCLUSION

The efficacy of IM olanzapine 10 mg in patients with exacerbation of schizophrenia with acute psychotic agitation was greater than IM placebo in the primary efficacy measure, PANSS-EC. Intramuscular olanzapine 10 mg was shown to be generally safe and tolerable, and could be a new option for treatment of schizophrenia in Japan.

TRIAL REGISTRATION

NCT00970281.

World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Schizophrenia, part 1: update 2012 on the acute treatment of schizophrenia and the management of treatment resistance

These updated guidelines are based on a first edition of the World Federation of Societies of Biological Psychiatry Guidelines for Biological Treatment of Schizophrenia published in 2005. For this 2012 revision, all available publications pertaining to the biological treatment of schizophrenia were reviewed systematically to allow for an evidence-based update. These guidelines provide evidence-based practice recommendations that are clinically and scientifically meaningful and these guidelines are intended to be used by all physicians diagnosing and treating people suffering from schizophrenia. Based on the first version of these guidelines, a systematic review of the MEDLINE/PUBMED database and the Cochrane Library, in addition to data extraction from national treatment guidelines, has been performed for this update. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into six levels of evidence (A-F; Bandelow et al. 2008b, World J Biol Psychiatry 9:242). This first part of the updated guidelines covers the general descriptions of antipsychotics and their side effects, the biological treatment of acute schizophrenia and the management of treatment-resistant schizophrenia.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia, Part 1: acute treatment of schizophrenia

These guide lines for the biological treatment of schizophrenia were developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBO). The goal during the development of these guidelines was to review systematically all available evidence pertaining to the treatment of schizophrenia, and to reach a consensus on a series of practice recommendations that are clinically and scientifically meaningful based on the available evidence. These guidelines are intended for use by all physicians seeing and treating people with schizophrenia. The data used for developing these guidelines have been extracted primarily from various national treatment guidelines and panels for schizophrenia, as well as from meta-analyses, reviews and randomised clinical trials on the efficacy of pharmacological and other biological treatment interventions identified by a search of the MEDLINE database and Cochrane Library. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into four levels of evidence (A-D). This first part of the guidelines covers disease definition, classification, epidemiology and course of schizophrenia, as well as the management of the acute phase treatment. These guidelines are primarily concerned with the biological treatment (including antipsychotic medication, other pharmacological treatment options, electroconvulsive therapy, adjunctive and novel therapeutic strategies) of adults suffering from schizophrenia.

Pharmacokinetic profile and clinical efficacy of long-acting risperidone: potential benefits of combining an atypical antipsychotic and a new delivery system

Continuous long-term antipsychotic therapy is required for patients with schizophrenia to optimise treatment benefits. The use of long-acting antipsychotic preparations can help to ensure compliance with therapy and has been shown to improve efficacy in relapse prevention when compared with oral agents. How- ever, the use of long-acting agents has been limited, since this approach to patient care has only been available with conventional drugs. The atypical antipsychotic agents have provided a new option for the treatment of schizophrenia. However, entwined with health system limitations, partial or non-compliance remains a problem with oral atypical antipsychotic agents. Combining the attributes of the atypical antipsychotic class with the pharmacokinetic profile and compliance advantages of a long-acting formulation could potentially be an important advance in the management of patients requiring continuous anti- psychotic therapy. This review considers the available clinical data supporting possible advantages for the only long-acting atypical agent currently available, long-acting risperidone, as a microsphere formulation. The drug-delivery technology employed provides a sustained therapeutic plasma level, with administration once every 2 weeks, and this is translated into improved symptom control and improved quality of life, even in patients already deemed clinically stable on an oral agent or on a conventional depot antipsychotic.

Efficacy and safety of long-acting risperidone in stable patients with schizoaffective disorder

BACKGROUND

The treatment of schizoaffective disorder is often complicated by the variety of symptoms that contribute to its pathology. Data from a large study (n=725), which included schizoaffective patients to assess the effect of long-acting risperidone, are presented.

METHOD

A multicenter, open-label study enrolled non-acute, clinically stable patients with schizoaffective disorder (n=110). Patients on a stable dose of antipsychotic for at least 4 weeks at study entry were switched to long-acting risperidone every 2 weeks for 50 weeks.

RESULTS

Mean Positive and Negative Syndrome Scale (PANSS) total scores (+/-S.E.) improved significantly (p<0.001) at each measured time point, including endpoint (-9.0+/-1.6), compared with baseline. Significant reductions were observed on mean PANSS cluster scores for both anxiety/depression (-1.3+/-0.4, p<0.001) and uncontrolled hostility/excitement (-0.7+/-0.3, p<0.05). In addition, scores improved significantly for positive symptoms (-2.2+/-0.5, p<0.001), negative symptoms (-3.1+/-0.5, p<0.001), and disorganized thoughts (-1.7+/-0.4, p<0.001). The overall subjective score of movement disorders was low at baseline (3.6+/-4.1) and had significantly decreased at endpoint (2.75; p<0.05). Patients were previously treated with antipsychotics for 398+/-790 days before being switched to long-acting risperidone.

LIMITATIONS

Although this was a 50-week study, which included over 100 patients with schizoaffective disorder, limitations include the open-label design and that it was not designed specifically to assess patients with this disorder. PANSS symptom domains previously defined by factor analytic methods were used for mood symptom measures. No specific mood symptom scales were administered in this study.

CONCLUSION

Patients with schizoaffective disorder, considered stable on their antipsychotic medication at study entry, experienced additional significant clinical improvements and minimal side effects with injections of long-acting risperidone over a 50-week study period.

Simultaneous determination of levomepromazine, midazolam and their major metabolites in human plasma by reversed-phase liquid chromatography

A sensitive and reliable high-performance liquid chromatographic (HPLC) assay is a prerequisite for pharmacokinetic analysis of continuous infusion of levomepromazine adjuvant to midazolam. We developed such a method to determine the levels of levomepromazine, midazolam and their major metabolites (levomepromazinesulfoxide, desmethyl-, didesmethyllevomepromazine, O-desmethyllevomepromazine and alpha-hydroxy-midazolam) simultaneously. Desmethylclomipramine was used as an internal standard (I.S.). The lower limit of quantification of this assay was set for levomepromazine 4.1 microg/l, levomepromazinesulfoxide 4.9 microg/l, O-desmethyllevomepromazine 18.4 microg/l, alpha-hydroxymidazolam 26.6 microg/l, midazolam 23.4 microg/l, didesmethyllevomepromazine 15.8 microg/l, and desmethyllevomepromazine 6.6 microg/l. The between- and within day assay variations were commonly below 5%. The recovery in human plasma for the different analytes varied between 85 and 11%. The accuracy of this assay varied between 95 and 105% for the different concentrations. The linearity of this assay was set between 25 and 800 microg/l (r(2)>0.999 of the regression line). The first results of pharmacokinetic analysis of midazolam indicated that half-life varied between 1.1 and 1.9 h. Pharmacokinetic analysis using a one-compartment model of levomepromazine revealed that the apparent volume of distribution was 4.1+/-2.4 l per kg lean body mass and the metabolic clearance was 309+/-225 l per hour per 70 kg. This assay proved to be robust and reproducible. It can reliably be used for further study of the pharmacokinetics of continuous infusion of levomepromazine.

Oxcarbazepine

The success of carbamazepine (CBZ) as a broad-spectrum antiepileptic drug (AED) has led to its use as first-line therapy in children and adults for partial and generalized tonic-clonic seizures. The limitations of CBZ include toxicity in sensitive individuals, autoinduction, which requires dose adjustment when therapy is initiated, and chronic hepatic induction, producing drug interactions when CBZ is used with AEDs and other drugs that undergo hepatic metabolism. One of two main products of CBZ microsomal metabolism, CBZ-10,11-epoxide (formed by oxidation of the double bond between C-10 and C-11), appears to provide antiepileptic efficacy but contributes significantly to clinical toxicity. The most common adverse effects of CBZ are central nervous system (CNS) symptoms, followed by gastrointestinal, hepatic, endocrine disturbances, and teratogenic effects. Oxcarbazepine (OXC) was developed to provide a compound chemically similar enough to CBZ to mimic its efficacy and overall safety while improving its side-effect profile. Biotransformation of OXC does not involve formation of an epoxide metabolite. Compared with the parent compound, hepatic microsomal enzyme induction and autoinduction are greatly reduced. The clinical efficacy of OXC compares favorably with CBZ in clinical trials. Clinical development of OXC began in Europe. Results of Phase I trials started to appear in the early 1980s. Controlled clinical trials, reported in the mid- to late 1980s, led to approval of OXC in many European countries, and now in over 50 nations around the world. United States multicenter clinical trials have recently been completed, and at this writing the drug is awaiting approval by the FDA. This article reviews the pharmacology, animal data, outcomes of published controlled clinical trials, postmarketing data, adverse experiences, and current recommendations for clinical use of OXC.

Induction of ethinylestradiol and levonorgestrel metabolism by oxcarbazepine in healthy women

PURPOSE

To evaluate the effect of oxcarbazepine (OCBZ) on the pharmacokinetic profile of steroid oral contraceptives.

METHODS

Twenty-two healthy women aged 18-44 years were recruited, and 16 of them completed the study. By using a randomized double-blind crossover design, each woman was studied in two different menstrual cycles, during which placebo or OCBZ (maintenance dosage, 1,200 mg/day) was given in randomized sequence for 26 consecutive days with a washout of at least one cycle in between. A steroid oral contraceptive containing 50 microg ethinylestradiol (EE) and 250 microg levonorgestrel (LN) was taken for the first 21 days of each cycle. Plasma concentrations of EE and LN were measured by gas chromatography-mass spectrometry in samples collected at regular intervals on days 21-23 of each cycle.

RESULTS

Compared with placebo, areas under the plasma concentration curves (AUC(0-24h, geometric means) decreased by 47% for both EE (from 1,677 to 886 pg.h/ml; p < 0.01) and LN (from 137 to 73 ng.h/ml; p < 0.01), during OCBZ treatment. Peak plasma EE concentrations decreased from 180 pg/ml during the placebo cycle to 117 pg/ml during the OCBZ cycle (p < 0.01), whereas peak plasma LN concentrations decreased from 10.2 to 7.7 ng/ml (p < 0.01). The half-lives of EE and LN also decreased from 13.6 to 7.9 h (p < 0.01) and from 28.8 to 15.8 h, respectively (p < 0.01).

CONCLUSIONS

OCBZ reduces plasma concentrations of the estrogen and progestagen components of steroid oral contraceptives, presumably by stimulating their CYP3A-mediated metabolism in the liver or gastrointestinal tract or both. Because this may lead to a decreased efficacy of the contraceptive pill, women treated with OCBZ should receive preferentially a high-dosage contraceptive and should be monitored for signs of reduced hormonal cover.

The new antiepileptic drugs and women: efficacy, reproductive health, pregnancy, and fetal outcome

As new antiepileptic drugs (AEDs) become available, physicians will define their appropriate use in particular patient populations. For women, the issues include gender-specific efficacy and tolerability, including the impact of the AED on reproductive health. Women with epilepsy who are treated with established AEDs appear to be at risk for compromised bone health, for disturbances in fertility, menstrual cyclicity, ovulatory function, and sexuality and, with some AEDs, for failure of hormonal contraception. Finally, pregnancy outcome may be adversely affected by the established AEDs, all of which are human teratogens. Felbamate (FBM), gabapentin (GBP), lamotrigine (LTG), oxcarbazepine (OCBZ), tiagabine (TGB), topiramate (TPM), and vigabatrin (VGB) were reviewed. The preclinical development process had not addressed all the issues of concern to women. Although gender-specific efficacy is routinely evaluated, impact on reproductive health is not. FBM, GBP, LTG, TGB, TPM, and VGB have similar efficacy in women and men. It is not known whether the new AEDs will affect bone health, fertility, the menstrual cycle, and sexuality. FBM, GBP, LTG, TGB, and probably VGB do not interfere with hormonal contraception. Whether these new AEDs are good choices for the pregnant woman with epilepsy awaits further experience in human pregnancy. However, animal reproductive toxicology studies appear promising. The limited number of human pregnancy exposures do not, thus far, signal a significant number or particular type of adverse outcomes. However, only with improved postmarketing surveillance can essential information about teratogenic effects by acquired in an acceptably short time.

Oxcarbazepine: clinical development program

Oxcarbazepine (OCBZ, Trileptal) is registered in several countries and has been well received by patients and physicians. However, newer standards in many other countries require additional data before registration can be achieved. For this reason, Ciba has implemented further clinical studies. OCBZ has a chemical structure that is closely related to carbamazepine (CBZ). In humans, OCBZ is not oxidatively metabolized, therefore causing little, if any, induction of hepatic enzymes. Because of this, and because of low protein-binding properties, OCBZ causes markedly fewer interactions with concomitant medications than most marketed antiepileptic drugs. OCBZ has been shown to have significantly fewer limiting side effects (described as side effects leading to discontinuation of treatment) than CBZ, while showing comparable efficacy. Many patients who are hypersensitive to CBZ can be treated with OCBZ. The usually administered dosage of OCBZ is approximately 50% higher than that of CBZ. However, better tolerability of OCBZ makes it possible to give higher dosages. The plasma concentration half-life of the active metabolite (monohydroxy derivative; MHD) makes it possible to administer OCBZ twice daily. No changes in dosage are necessary in patients with impaired renal function unless creatinine clearance is below 30 ml/min. In patients with such severely reduced creatinine clearance, the dose of OCBZ should be halved. Specific questions e.g., such as whether OCBZ causes hepatic enzyme induction at higher doses and the effect of OCBZ on intrinsic sex hormones, will be answered in future studies. In addition, the tolerability and pharmacokinetics of OCBZ in specific target populations such as the elderly, children, and hepatically impaired patients will be addressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxcarbazepine: pharmacokinetic interactions and their clinical relevance

Antiepileptic drug (AED) interactions are a common problem during epilepsy treatment. Oxcarbazepine (OCBZ) is a keto homologue of carbamazepine (CBZ) with a completely different metabolic profile. In humans, the keto group is rapidly and quantitatively reduced to form a monohydroxy derivative (MHD), which is the main active agent during OCBZ therapy. MHD is eliminated by renal excretion, glucuronidation and, marginally, by hydroxylation to a diol derivative. This metabolic profile, and in particular the limited involvement of oxidative microsomal enzymes, suggests that OCBZ may have fewer drug interactions compared with traditional AEDs. This possibility has been investigated in experimental studies and, retrospectively, in data obtained from clinical trials. The capacity of OCBZ to induce microsomal enzymes of the P-450 family has mostly been examined by use of antipyrine and CBZ kinetics as markers. The results suggest that OCBZ has little enzyme inducing capacity. In clinical trials in which OCBZ was substituted for CBZ, plasma concentrations of concomitant AEDs were increased, possibly as a consequence of total or partial de-induction. OCBZ interference with other drugs has been evaluated for warfarin, felodipine, and oral contraceptives, three medications strongly influenced by enzyme-inducing AEDs. OCBZ does not modify the anticoagulant effect of warfarin, whereas some reduction in felodipine concentration and a clinically significant reduction of contraceptive drug levels and efficacy were observed. Polytherapy with established AEDs does not significantly modify OCBZ disposition (MHD kinetics); however, available information is not extensive. Finally, the action on OCBZ kinetics of a group of drugs (verapamil, cimetidine, erythromycin, dextropropoxyphene, and viloxazine) known to inhibit the metabolism of some AEDs has been studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Possible interaction between oxcarbazepine and an oral contraceptive

The effect of oxcarbazepine (OCBZ) on the kinetics of an oral contraceptive containing ethinyloestradiol (EE) and levonorgestrel (LNG) was investigated in 13 healthy female volunteers who had previously received the contraceptive for at least 3 months. After 15 days of the first study cycle, each subject received, in addition to the oral contraceptive, 300 mg OCBZ on day 16, 300 mg twice daily on day 17, and 300 mg three times daily from day 18 of the first cycle to day 18 of the next menstrual cycle. The area under the curve values for both EE and LNG decreased when OCBZ was given with the oral contraceptive (p = 0.006, analysis of variance). The results indicate that OCBZ, like most antiepileptic drugs (AEDs), decreases the bioavailability of EE and LNG, perhaps by affecting metabolism or protein binding.