An isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure for the quantification of carbamazepine-10,11-epoxide in human serum and plasma.

OBJECTIVES: A reference measurement procedure (RMP) using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) was developed and validated with the aim of accurately measuring carbamazepine-10,11-epoxide concentrations in human serum and plasma. METHODS: To establish traceability to SI units, the absolute content of the reference material was determined using quantitative nuclear magnetic resonance (qNMR) spectroscopy. As sample preparation a protein precipitation protocol followed by a high dilution step was established. Chromatographic separation from carbamazepine and potential metabolites was achieved using a C18 stationary phase. Selectivity, specificity, matrix effects, precision and accuracy, inter-laboratory equivalence, and uncertainty of measurement were evaluated based on guidelines from the Clinical and Laboratory Standards Institute, the International Conference on Harmonization, and the Guide to the Expression of Uncertainty in Measurement. RESULTS: The RMP demonstrated very good selectivity and specificity, showing no evidence of a matrix effect. This enabled accurate quantification of carbamazepine-epoxide in the concentration range of 0.0400-12.0 µg/mL. The intermediate precision was found to be less than 2.1 %, and the repeatability coefficient of variation (CV) ranged from 1.2 to 1.8 % across all concentration levels. Regarding accuracy, the relative mean bias varied from 1.4 to 2.5 % for native serum levels and from 1.4 to 3.5 % for Li-heparin plasma levels. The measurement uncertainty for single measurements ranged from 1.6 to 2.1 %. CONCLUSIONS: In this study, we introduce a new LC-MS/MS-based candidate RMP for accurately measuring carbamazepine-10,11-epoxide in human serum and plasma. This novel method offers a traceable and dependable platform, making it suitable for standardizing routine assays and assessing clinically relevant samples.

Overnight switch from carbamazepine to eslicarbazepine in a real-life clinical scenario: a retrospective study.

BACKGROUND: Carbamazepine (CBZ) is a first-choice anti-seizure medication (ASM) whose efficacy is often invalidated by adverse effects (AEs). Eslicarbazepine (ESL) is a structural derivative of CBZ with better pharmacokinetic/tolerability profiles. We describe our experience of the overnight CBZ to ESL switch in people with epilepsy (PwE) to improve seizure control, AEs, and ASMs adherence. METHODS: We retrospectively included 19 PwE (12 females, 53 ± 21 years old) who underwent CBZ to ESL overnight switch due to single/multiple issues: poor efficacy (pEff, N = 8, 42%), tolerability (pToll, N = 11, 58%), adherence (pAdh, N = 2, 10%). 9/19 (47%) had psychiatric comorbidities. Clinical variables, seizure frequency, and AEs were recorded at switch time (T0) after 3.5 ± 3 (T1) and 6.5 ± 1.5 months (T2). RESULTS: At T1, in pEff group, 1/8 (13%) was seizure free, 2/8 (25%) were responders (> 50% seizure reduction), 2/8 (25%) had no seizure changes, 3/8 (37%) had seizure worsening; the latter were those with the most severe epilepsy and encephalopathy. In pToll group, all PwE experienced AEs disappearance/amelioration. In pAdh group, all PwE reported adherence amelioration. Four dropouts. At T2, no changes were recorded within groups, while in the whole sample, 6/15 (40%) were responders, and 4/15 (27%) were seizure-free. No one complained of Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation psychiatric worsening, while 6/19 (32%) experienced mood/behavior benefits. CONCLUSIONS: CBZ to ESL overnight switch offers an opportunity to improve efficacy, tolerability, adherence, and psychiatric symptoms.

Intravenous Lidocaine Response as a Predictor for Oral Oxcarbazepine Efficacy in Neuropathic Pain Syndrome: A Prospective Cohort Study.

BACKGROUND Providing pain relief for patients with neuropathic pain syndrome (NPS) is difficult, as sodium-channel blockers pose serious adverse events (AEs). Intravenous (i.v.) lidocaine infusion responses may identify patients likely to benefit from oral sodium channel blockers. We evaluated i.v. lidocaine responses to predict oral oxcarbazepine (OXC) efficacy in patients with NPS. MATERIAL AND METHODS This prospective cohort study administered one-time 3 mg/kg i.v. lidocaine infusion to patients with NPS. Numeric rating scale (NRS) pain scores and AEs were observed. Next, OXC 150 mg was prescribed; dosages were increased by 150 mg every 3 days until ≥50% pain reduction or the maximum tolerable dose or 1800 mg/day was reached. NRS, rescue drug requirements, and AEs were evaluated by phone at 1, 3, and 5 weeks and clinic visits at 2, 4, and 6 weeks. Depression, Anxiety & Stress Scales 21 (DASS-21), and EuroQol-Five Dimensions-Five Levels (EQ-5D-5L) questionnaires were assessed at baseline and in week 6. RESULTS Of 46 patients, 14 discontinued due to intolerable AEs, and 32 were in the final analysis. Average post-intervention NRS significantly decreased from 6.8±1.7 (baseline) to 3.8±2.0 (lidocaine) and 4.1±2.3 (OXC); P<0.001. Negative and positive predictive values for OXC efficacy were 76.2% (95% CI: 61.6-86.5%) and 54.5% (95% CI: 32-75.4%), respectively. Six weeks after OXC treatment, 20 and 11 patients achieved ≥30% pain reduction and ≥50% pain relief, respectively. EQ-5D-5L (P=0.018) and DASS-21 stress dimension (P<0.001) significantly improved. CONCLUSIONS Negative responses to i.v. lidocaine predicted a lack of oral OXC response. AEs of OXC may have obscured an analgesic effect.

Polymorphism and Pharmacological Assessment of Carbamazepine.

This work provides insight into carbamazepine polymorphs (Forms I, II, III, IV, and V), with reports on the cytoprotective, exploratory, motor, CNS-depressant, and anticonvulsant properties of carbamazepine (CBZ), carbamazepine formulation (CBZ-F), topiramate (TOP), oxcarbazepine (OXC), and diazepam (DZP) in mice. Structural analysis highlighted the significant difference in molecular conformations, which directly influence the physicochemical properties; and density functional theory description provided indications about CBZ reactivity and stability. In addition to neuron viability assessment in vitro, animals were treated orally with vehicle 10 mL/kg, as well as CBZ, CBZ-F, TOP, OXC, and DZP at the dose of 5 mg/kg and exposed to open-field, rotarod, barbiturate sleep induction and pentylenetetrazol (PTZ 70 mg/kg)-induced seizure. The involvement of GABAergic mechanisms in the activity of these drugs was evaluated with the intraperitoneal pretreatment of flumazenil (2 mg/kg). The CBZ, CBZ-F, and TOP mildly preserved neuronal viability. The CBZ-F and the reference AEDs potentiated barbiturate sleep, altered motor activities, and attenuated PTZ-induced convulsion. However, flumazenil pretreatment blocked these effects. Additional preclinical assessments could further establish the promising utility of CBZ-F in clinical settings while expanding the scope of AED formulations and designs.

Chronic Treatment with Oxcarbazepine Attenuates Its Anticonvulsant Effect in the Maximal Electroshock Model in Mice.

The objective of this study was to assess the impact of acute and chronic treatment with oxcarbazepine on its anticonvulsant activity, neurological adverse effects, and protective index in mice. Oxcarbazepine was administered in four protocols: once or twice daily for one week (7 × 1 or 7 × 2) and once or twice daily for two weeks (14 × 1 or 14 × 2). A single dose of the drug was employed as a control. The anticonvulsant effect was evaluated in the maximal electroshock test in mice. Motor and long-term memory impairment were assessed using the chimney test and the passive avoidance task, respectively. The concentrations of oxcarbazepine in the brain and plasma were determined via high-performance liquid chromatography. Two weeks of oxcarbazepine treatment resulted in a significant reduction in the anticonvulsant (in the 14 × 1; 14 × 2 protocols) and neurotoxic (in the 14 × 2 schedule) effects of this drug. In contrast, the protective index for oxcarbazepine in the 14 × 2 protocol was found to be lower than that calculated for the control. No significant deficits in memory or motor coordination were observed following repeated administration of oxcarbazepine. The plasma and brain concentrations of this anticonvulsant were found to be significantly higher in the one-week protocols. Chronic treatment with oxcarbazepine may result in the development of tolerance to its anticonvulsant and neurotoxic effects, which appears to be dependent on pharmacodynamic mechanisms.

LC-MS/MS quantification of levetiracetam, lamotrigine and 10-hydroxycarbazepine in TDM of epileptic patients.

BACKGROUND: To minimize drug-related toxicity and monitor dosing regimens, an ultra-sensitive, simple and high-throughput analytical method for therapeutic drug monitoring is required. A novel LC-MS/MS bioassay of levetiracetam, lamotrigine and 10-hydroxycarbazepine in human plasma was established. The analytes were separated on a Hypersil GOLD™ C18 column under a 2.5 min isocratic elution after one-step protein precipitation. MS detection was performed under electrospray ionization positive-mode fitted with selected reaction monitoring. The validated ranges were 0.1-20 µg/ml for LTG, 0.3-60 µg/ml for 10-hydroxycarbazepine and levetiracetam. The intra- and inter-batches of precision and accuracy was within ±15%. The novel method met all other criteria. CONCLUSION: This method can be used to monitor drug concentrations and decision-making in epileptic patients.

Approach to the Dynamic of Carbamazepine and its Main Metabolites in Soil Contamination through the Reuse of Wastewater and Sewage Sludge.

The release of pharmaceutically active compounds to the soils through the application of sewage sludge and the irrigation with wastewater, or even with surface water, is constant. The adsorption of these compounds onto the soil is one of the key factors affecting their fate in the environment and their potential environmental risks. In this work, the adsorption of carbamazepine (CBZ) and its metabolites, 3-hydroxy-carbamazepine (3OH-CBZ), carbamazepine-10,11-dihydro-10,11-epoxide (EP-CBZ), and 10,11-dihydro-10-hydroxycarbamazepine (10OH-CBZ), in three Mediterranean soils was evaluated using single-solute and four-solute experiments. The highest adsorptions were measured for 3OH-CBZ, followed by CBZ, EP-CBZ, and 10OH-CBZ, in that order. A high influence of the physicochemical characteristics of the compounds, pH, and soil characteristics in the adsorption of the studied compounds was observed and corroborated by the statistical analysis of the results. Moreover, a good fit was observed in the three isotherm models evaluated (linear, Freundlich, and Langmuir) in single-solute experiments (R2 > 0.90). However, a decrease of the measured adsorptions and a worse fit to the isotherm models were observed in the case of multiple-solute experiments. This could be mainly due to the competition established between the studied compounds for the active sites of the soils.

Development and application of water-compatible molecularly imprinted polymers for the selective extraction of carbamazepine from environmental waters.

A molecularly imprinted polymer (MIP) was designed in order to allow the selective solid-phase extraction of carbamazepine (CBZ), an anticonvulsant and mood-stabilizing drug, at ultra-trace level from aqueous environmental samples. A structural analog of CBZ was selected as a dummy template and different synthesis conditions were screened. The selectivity of the resulting imprinted polymers was evaluated by studying the retention of CBZ in a solvent similar to the one used for the synthesis. The presence of imprinted cavities in the polymers was then demonstrated by comparing the elution profiles (obtained by using MIP and a non-imprinted polymer, NIP, as a control) of the template, of CBZ, and of a structural analog of CBZ. Then, the extraction procedure was further optimized for the treatment of aqueous samples on the two most promising MIPs, with special attention being paid to the volume and composition of the percolation and washing solutions. The best MIP provided a highly selective retention in tap water with 81% extraction recovery for CBZ in the elution fraction of the MIP and only 14% for NIP. The repeatability of the extraction procedure was demonstrated for both tap and river waters (RSD below 4% in river water) for the drugs CBZ, oxcarbamazepine, and one metabolite (carbamazepine 10,11-epoxide). A MIP capacity of 1.15 µmol g-1 was determined. Finally, an analytical procedure involving the MIP was developed allowing the detection of CBZ at a concentration level of only a few nanograms per liter in river water. The selectivity provided by the MIP resulted in a 3000-fold increase of the signal-to-noise ratio in LC/MS analysis as compared to the use of conventional sorbent. Graphical abstract.

Population pharmacokinetics of oxcarbazepine active metabolite in Chinese paediatric epilepsy patients and its application in individualised dosage regimens.

PURPOSE: Oxcarbazepine (OXC) is an antiepileptic drug metabolised to active 10-monohydroxy derivative (MHD) following oral administration. There are no MHD population pharmacokinetic (PPK) models that describe the influence of genetic factors on MHD pharmacokinetics (PK). We developed a PPK model of MHD to investigate gene polymorphism of enzymes associated with MHD PK in Chinese paediatric epilepsy patients and evaluated its utility for dose individualisation. METHODS: Data were prospectively collected from 141 paediatric epilepsy patients (aged ≤ 14 years) who received OXC therapy at the First Affiliated Hospital of Fujian Medical University. The trough concentrations at steady state were determined by enzyme-multiplied immunoassay. Patients were genotyped for four single nucleotide polymorphisms (UGT2B7 802T>C, UGT1A9 I399C>T, ABCB1 3435C>T, and ABCB2 1249G>A). Patient gender, age, body weight (BW), hepatorenal function, and co-administrations were recorded. The PPK model was developed using nonlinear mixed-effects modelling software. The clinical performance of the final model was evaluated by including additional paediatric patients (n = 20) in the validation group. RESULTS: Oral clearance of MHD was significantly influenced by BW. The MHD PK was unrelated to the other covariates, such as the four single nucleotide polymorphisms and co-administration with new-generation antiepileptic drugs. The final BW-dependent exponent model showed the best fit with our data and predicted the trough concentrations in the validation group more accurately than the basic model. A new dosing strategy combining the dosage guideline and Bayesian method is proposed to individualise OXC regimens. CONCLUSION: A PPK model was established to estimate individual MHD clearance in paediatric patients taking OXC to develop individualised OXC dosing regimens for Chinese paediatric epilepsy patients.

Polymorphic Phase Transitions in Carbamazepine and 10,11-Dihydrocarbamazepine.

Temperature-induced phase transitions in carbamazepine (CBZ) and 10,11-dihydrocarbamazepine (DHC) were studied by simultaneous differential scanning calorimetry-X-ray diffraction in this work. The transitions generally involve a transitional melt phase which is quickly followed by recrystallisation. The expansions of the unit cell as a function of temperature could be quantified and allow us to determine a directional order of stability in relation to the lattice constants. Dihydrocarbamazepine form II undergoes a conversion to form I by a localised melt phase. Carbamazepine (CBZ) form IV converts to form I at 182 °C, again by a localised intermediate melt phase. CBZ form II converted to form I at 119 °C by a pathway that appears to have included some melting, and form III underwent a part melt-recrystallisation and a part sublimation-recrystallisation to form I.

Hepatitis C-related cryoglobulinemic neuropathy: potential role of oxcarbazepine for pain control.

BACKGROUND: Peripheral neuropathy is one most common, limiting and invalidating neurological symptom in subjects with hepatitis C virus and mixed cryoglobulinemia. Notably, the medical therapy proposed to eradicate HCV, can frequently exacerbate the painful neuropathy. Therefore, neuropathy therapies are insufficient and inadequate, and comprise immunosuppressive drugs, such as steroid or cyclosporine, intravenous immunoglobulin or plasma exchange. These have shown variable success in case reports, with a presumably temporary effect, but with major side effects. METHODS: We assessed the effects of oxcarbazepine treatment in 67 cases of cryoglobulinemia related neuropathy, who did not respond to either steroid or Gabapentin, or Pregabalin. Oxcarbazepine was chosen based on the promising preliminary results. RESULTS: Patients treated with Oxcarbazepine showed a rapid, discrete and persistent relief of polyneuropathic signs, without consistent side effects, and with a limited interaction with concomitant drugs. CONCLUSIONS: These data favor the use of oxcarbazepine as a useful tool in the management of neuropathic pain associated with Hepatitis-C cryoglobulin neuropathy.

4-Substituted carbamazepine derivatives: Conformational analysis and sodium channel-blocking properties.

The physicochemical properties of 4-substituted carbamazepine derivatives were investigated. It was elucidated that the 4-substitution is not effective in reducing the rotations (E/Z) about the N-C1' axes around the outer carbamoyl moiety. However, the atropisomers were isolated with high stereochemical stability, meaning that the 4-substitution reduced the butterfly motion of the tricyclic ring system efficiently. The Cl/CH3-substituted carbamazepine derivatives showed greater inhibitory effects on hNav1.2 channel currents compared with carbamazepine, although no difference in the activity between enantiomers was observed.

Eslicarbazepine acetate as adjunctive treatment in partial-onset epilepsy.

OBJECTIVE: The aim of the study was to assess the clinical response to eslicarbazepine acetate (ESL) as add-on therapy in adult patients with partial-onset epilepsy by means of the time-to-baseline seizure count method. METHODS: We retrospectively identified consecutive patients with partial-onset seizures, with or without secondary generalization, prescribed to ESL add-on therapy. The primary endpoint was the time-to-baseline monthly seizure count. Subgroup analysis was performed according to carbamazepine (CBZ)/oxcarbazepine (OXC) status (prior vs never use). Secondary outcomes were the rate of treatment-related adverse events (AEs) and the AEs affecting ≥5% of patients. RESULTS: One-hundred and eighteen patients were included. The median time-to-baseline monthly seizure count was 46 (35-101) days in the overall study cohort. The number of concomitant anti-epileptic drugs (AEDs) was associated with the time-to-endpoint (adjusted hazard ratio [adj HR]=2.22, 95% CI 1.18-4.14, P=.013 for two AEDs vs one; adj HR=3.65, 95% CI 1.66-8.06, P=.001 for three or more AEDs vs one). Groupwise, the median times-to-baseline seizure count were 47 (35-97) and 43 (34-103) in patients with prior and never exposure to CBZ/OXC, respectively (P for log-rank test=.807). Adverse events occurred in 53.4% (63 of 118) of patients; the most frequently reported were dizziness (13.6%), somnolence (11.9%), nausea (6.8%), and fatigue (5.1%). CONCLUSIONS: Add-on ESL improved seizure control and was overall well-tolerated in adult patients with partial-onset epilepsy.

Adverse effects of anti-epileptics in trigeminal neuralgiform pain.

BACKGROUND: Side effects of anti-epileptic drugs (AEDs) have not been adequately documented in trigeminal neuralgia and its variants. The aim of this observational cross-sectional study was to compare the A-B Neuropsychological Assessment Schedule (ABNAS), which measures cognitive side effects to the Adverse Events Profile (AEP), which looks at a broader range of side effects, and to investigate drug/dosage relationships with questionnaire scores to help determine a point at which a drug change would be indicated. METHODS: One hundred five patients were recruited from a facial pain clinic, over a 10-month period. Self-complete questionnaire scores were compared between patients using different AEDs. RESULTS: A-B Neuropsychological Assessment Schedule score correlated well with AEP indicating that cognitive side effects were a significant burden. Toxic range on the ABNAS was estimated to occur when scores were >43/72 (95% CI: 37.4-48.6). Polytherapy is weakly associated with the higher scores. Oxcarbazepine dosage was found to linearly correlate with AEP and ABNAS scores, better than carbamazepine dosage. Memory alteration was least common with lamotrigine and oxcarbazepine, and there was less association between fatigues with oxcarbazepine/pregabalin. CONCLUSION: Anti-epileptic drugs have significant side effects. The ABNAS questionnaire is a useful tool along with the AEP to recognize and monitor AEDs' side effects and to help to adjust medications to optimal dosage.

Risperidone for psychosis-induced aggression or agitation (rapid tranquillisation).

BACKGROUND: Aggressive, agitated or violent behaviour due to psychosis constitutes an emergency psychiatric treatment where fast-acting interventions are required. Risperidone is a widely accessible antipsychotic that can be used to manage psychosis-induced aggression or agitation. OBJECTIVES: To examine whether oral risperidone alone is an effective treatment for psychosis-induced aggression or agitation. SEARCH METHODS: We searched the Cochrane Schizophrenia Group's Study-Based Register of Trials (up to April 2017); this register is compiled by systematic searches of major resources (including AMED, BIOSIS CINAHL, Embase, MEDLINE, PsycINFO, PubMed, and registries of clinical trials) and their monthly updates, handsearches, grey literature, and conference proceedings. There are no language, date, document type, or publication status limitations for inclusion of records into the register. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing rapid use of risperidone and other drugs, combinations of drugs or placebo for people exhibiting aggression or agitation (or both) thought to be due to psychosis. DATA COLLECTION AND ANALYSIS: We independently inspected all citations from searches, identified relevant abstracts, and independently extracted data from all included studies. For binary data we calculated risk ratio (RR) and for continuous data we calculated mean difference (MD), all with 95% confidence intervals (CI) and used a fixed-effect model. We assessed risk of bias for the included studies and used the GRADE approach to produce a 'Summary of findings' tables. MAIN RESULTS: The review now contains data from nine trials (total n = 582) reporting on five comparisons. Due to risk of bias, small size of trials, indirectness of outcome measures and a paucity of investigated and reported 'pragmatic' outcomes, evidence was graded as very-low quality. None of the included studies provided useable data on our primary outcome 'tranquillisation or asleep' by 30 minutes, repeated need for tranquillisation or any economic outcomes. Data were available for our other main outcomes of agitation or aggression, needing restraint, and incidence of adverse effects.Risperidone versus haloperidol (up to 24 hours follow-up)For the outcome, specific behaviour - agitation, no clear difference was found between risperidone and haloperidol in terms of efficacy, measured as at least 50% reduction in the Positive and Negative Syndrome Scale - Psychotic Agitation Sub-score (PANSS-PAS) (RR 1.04, 95% CI 0.86 to 1.26; participants = 124; studies = 1; very low-quality evidence) and no effect was observed for need to use restraints (RR 2.00, 95% CI 0.43 to 9.21; participants = 28; studies = 1; very low-quality evidence). Incidence of adverse effects was similar between treatment groups (RR 0.94, 95% CI 0.54 to 1.66; participants = 124; studies = 1; very low-quality evidence).Risperidone versus olanzapineOne small trial (n = 29) reported useable data for the comparison risperidone versus olanzapine. No effect was observed for agitation measured as PANSS-PAS endpoint score at two hours (MD 2.50, 95% CI -2.46 to 7.46; very low-quality evidence); need to use restraints at four days (RR 1.43, 95% CI 0.39 to 5.28; very-low quality evidence); specific movement disorders measured as Behavioural Activity Rating Scale (BARS) endpoint score at four days (MD 0.20, 95% CI -0.43 to 0.83; very low-quality evidence).Risperidone versus quetiapineOne trial reported (n = 40) useable data for the comparison risperidone versus quetiapine. Aggression was measured using the Modified Overt Aggression Scale (MOAS) endpoint score at two weeks. A clear difference, favouring quetiapine was observed (MD 1.80, 95% CI 0.20 to 3.40; very-low quality evidence). No evidence of a difference between treatment groups could be observed for incidence of akathisia after 24 hours (RR 1.67, 95% CI 0.46 to 6.06; very low-quality evidence). Two participants allocated to risperidone and one allocated to quetiapine experienced myocardial ischaemia during the trial.Risperidone versus risperidone + oxcarbazepineOne trial (n = 68) measured agitation using the Positive and Negative Syndrome Scale - Excited Component.(PANSS-EC) endpoint score and found a clear difference, favouring the combination treatment at one week (MD 2.70, 95% CI 0.42 to 4.98; very low-quality evidence), but no effect was observed for global state using Clinical Global Impression - Improvement (CGI-I) endpoint score at one week (MD -0.20, 95% CI -0.61 to 0.21; very-low quality evidence). Incidence of extrapyramidal symptoms after 24 hours was similar between treatment groups (RR 1.59, 95% CI 0.49 to 5.14; very-low quality evidence).Risperidone versus risperidone + valproic acidTwo trials compared risperidone with a combination of risperidone plus valproic acid. No clear differences between the treatment groups were observed for aggression (MOAS endpoint score at three days: MD 1.07, 95% CI -0.20 to 2.34; participants = 54; studies = 1; very low-quality evidence) or incidence of akathisia after 24 hours: RR 0.75, 95% CI 0.28 to 2.03; participants = 122; studies = 2; very low-quality evidence). AUTHORS' CONCLUSIONS: Overall, results for the main outcomes show no real effect for risperidone. The only data available for use in this review are from nine under-sampled trials and the evidence available is of very low quality. This casts uncertainty on the role of risperidone in rapid tranquillisation for people with psychosis-induced aggression. High-quality pragmatic RCTs are feasible and are needed before clear recommendations can be drawn on the use of risperidone for psychosis-induced aggression or agitation.

The genotoxic effect of oxcarbazepine on mice blood lymphocytes.

This study was conducted to assess the amount of DNA damage caused by Oxcarbazepine (OXC) through single cell gel electrophoresis (SCGE) technique/comet assay. OXC derived from dibenzazepine series is an effective second generation antiepileptic drug (AED) for both children and adults. Side effects like genotoxic effects of AEDs are of prime importance resulting from toxic metabolites, free radicals and reactive oxygen species (ROS). Forty Eight adult male Bagg's albino mice (BALB/c) were randomly classified into eight groups, each comprising of six animals. Two of these groups were control and six were tested groups. Control groups were injected with 1% tween 80 while tested groups were injected with 10, 20, and 40 mg/kg-day OXC for seven days (acute therapy) and 28 days (subchronic therapy) in peritoneal cavity. Blood samples were collected by cardiac puncture and subjected to comet assay for the analysis of DNA damage. Per sample 100 cells were scored and classified according to comet tail length. The results showed that OXC in acute and long term therapies had significantly higher (p < 0.05) genotoxicity in treated groups as compared to control groups. Our study suggests that OXC may cause significant DNA damage in both acute as well as in subchronic therapies.

Carbamazepine- and oxcarbazepine-induced hyponatremia in people with epilepsy.

OBJECTIVE: To ascertain possible determinants of carbamazepine (CBZ)- and oxcarbazepine (OXC)-induced hyponatremia in a large cohort of people with epilepsy. METHODS: We collected data on serum sodium levels in people with epilepsy who were attending a tertiary epilepsy center while on treatment with CBZ or OXC. We defined hyponatremia as Na+ ≤134 mEq/L and severe hyponatremia as Na+ ≤128 mEq/L. RESULTS: We identified 1,782 people who had used CBZ (n = 1,424) or OXC (n = 358), of whom 50 were treated with both drugs. Data on sodium level measurements were available in 1,132 on CBZ and in 289 on OXC. Hyponatremia occurred in 26% of those taking CBZ and 46% of those taking OXC. This was severe in 7% in the CBZ group and 22% in the OXC group. Hyponatremia was symptomatic in 48% and led to admissions in 3%. Age over 40 years, high serum levels of CBZ and OXC, and concomitant use of other antiepileptic drugs were the main risk factors for hyponatremia in both treatment groups. Female patients on OXC were at a higher risk than male patients of hyponatremia. The risk of hyponatremia on CBZ was significantly associated with the risk of hyponatremia on OXC within a subgroup that used both drugs consecutively. SIGNIFICANCE: Hyponatremia is a common problem in people taking CBZ or OXC. Regular ascertainment of sodium levels in those taking either drug is recommended and results should be acted on.

Serum protein binding of 25 antiepileptic drugs in a routine clinical setting: A comparison of free non-protein-bound concentrations.

OBJECTIVE: Given that only the free non-protein-bound concentration of an antiepileptic drug (AED) crosses the blood-brain barrier, entering the brain and producing an antiepileptic effect, knowledge and measurement of the free drug fraction is important. Such data are sparse, particularly for newer AEDs, and have arisen from the use of disparate methodologies and settings over the past six decades. We report on the protein binding of 25 AEDs that are available for clinical use, along with two pharmacologically active metabolites (carbamazepine-epoxide and N-desmethyl clobazam), using standardized methodology and under set conditions. METHODS: The protein binding of the various AEDs was undertaken in sera of 278 patients with epilepsy. Separation of the free non-protein-bound component was achieved by using ultracentrifugation (Amicon Centrifree Micropartition System) under set conditions: 500 µl serum volume; centrifugation at 1,000 g for 15 min, and at 25°C. Free and total AED concentrations were measured by use of fully validated liquid chromatography/mass spectroscopy (LC/MS) techniques. RESULTS: Gabapentin and pregabalin are non-protein-bound, whereas highly bound AEDs (≥88%) include clobazam, clonazepam, perampanel, retigabine, stiripentol, tiagabine, and valproic acid as well as the N-desmethyl-clobazam (89%) metabolite. The minimally bound drugs (<22%) include ethosuximide (21.8%), lacosamide (14.0%), levetiracetam (3.4%), topiramate, (19.5%) and vigabatrin (17.1%). Ten of the 25 AEDs exhibit moderate protein binding (mean range 27.7-74.8%). SIGNIFICANCE: These data provide a comprehensive comparison of serum protein binding of all available AEDs including the metabolites, carbamazepine-epoxide and N-desmethyl-clobazam. Knowledge of the free fraction of these AEDs can be used to optimize epilepsy treatment.

Comparison of levetiracetam and oxcarbazepine monotherapy among Korean patients with newly diagnosed focal epilepsy: A long-term, randomized, open-label trial.

This open-label, multicenter, randomized phase IV trial (NCT01498822) of noninferiority design compared the long-term effectiveness, safety, and tolerability of levetiracetam (LEV) monotherapy with those of oxcarbazepine (OXC) monotherapy in adults with newly diagnosed focal epilepsy. Korean patients (16-80 years), with ≥2 unprovoked focal seizures in the year preceding the trial, who had not taken any antiepileptic drugs (AEDs) in the last 6 months, were randomized to receive LEV or OXC (1:1). Effectiveness, safety, and tolerability were assessed over a 50-week period. Treatment failure rates (per protocol set) were 15/118 (12.7%) in the LEV-treated group and 30/128 (23.4%) in the OXC-treated group, an absolute difference of -10.7% (95% confidence interval [CI] -20.2, -1.2). Because the upper 95% CI limit was less than the pre-specified noninferiority margin of 15%, LEV was considered noninferior to OXC. Twenty-four-week and 48-week seizure freedom rates were 53.8% and 34.7% for LEV vs. 58.5% and 40.9% for OXC. Both LEV and OXC were well tolerated, with 8.7% and 8.6% of patients reporting serious treatment-emergent adverse events, respectively. By comparing LEV with OXC, another newer AED, LEV can be considered a useful option as initial monotherapy for patients with newly diagnosed focal epilepsy.

Rationale for an adjunctive therapy with fenofibrate in pharmacoresistant nocturnal frontal lobe epilepsy.

OBJECTIVE: Nocturnal frontal lobe epilepsy (NFLE) is an idiopathic partial epilepsy with a family history in about 25% of cases, with autosomal dominant inheritance (autosomal dominant NFLE [ADNFLE]). Traditional antiepileptic drugs are effective in about 55% of patients, whereas the rest remains refractory. One of the key pathogenetic mechanisms is a gain of function of neuronal nicotinic acetylcholine receptors (nAChRs) containing the mutated α4 or ß2 subunits. Fenofibrate, a common lipid-regulating drug, is an agonist at peroxisome proliferator-activated receptor alpha (PPARα) that is a ligand-activated transcription factor, which negatively modulates the function of ß2-containing nAChR. To test clinical efficacy of adjunctive therapy with fenofibrate in pharmacoresistant ADNFLE\NFLE patients, we first demonstrated the effectiveness of fenofibrate in a mutated mouse model displaying both disease genotype and phenotype. METHODS: We first tested the efficacy of fenofibrate in transgenic mice carrying the mutation in the α4-nAChR subunit (Chrna4S252F) homologous to that found in humans. Subsequently, an add-on protocol was implemented in a clinical setting and fenofibrate was administered to pharmacoresistant NFLE patients. RESULTS: Here, we show that a chronic fenofibrate diet markedly reduced the frequency of large inhibitory postsynaptic currents (IPSCs) recorded from cortical pyramidal neurons in Chrna4S252F mice, and prevented nicotine-induced increase of IPSC frequency. Moreover, fenofibrate abolished differences between genotypes in the frequency of sleep-related movements observed under basal conditions. Patients affected by NFLE, nonresponders to traditional therapy, by means of adjunctive therapy with fenofibrate displayed a reduction of seizure frequency. Furthermore, digital video-polysomnographic recordings acquired in NFLE subjects after 6 months of adjunctive fenofibrate substantiated the significant effects on control of motor-behavioral seizures. SIGNIFICANCE: Our preclinical and clinical studies suggest PPARα as a novel disease-modifying target for antiepileptic drugs due to its ability to regulate dysfunctional nAChRs.