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Heger K, Burns ML, Nikanorova M, Johannessen SI, Johannessen Landmark C. Pharmacokinetic Variability of Rufinamide and Stiripentol in Children with Refractory Epilepsy: A Retrospective Study of Therapeutic Drug Monitoring from the National Epilepsy Centers in Denmark and Norway. Ther Drug Monit 2024:00007691-990000000-00228. [PMID: 38758628 DOI: 10.1097/ftd.0000000000001219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/03/2024] [Indexed: 05/19/2024]
Abstract
BACKGROUND Rufinamide and stiripentol, orphan drugs used in Lennox-Gastaut and Dravet syndromes, respectively, are antiseizure medications (ASMs), often administered to children; however, pharmacokinetic studies are lacking. The authors compared the pharmacokinetic variability of these drugs with respect to the dose, serum concentrations, comedication, age, and duration of treatment. METHODS Children and adolescents (<18 years) whose serum concentrations were measured were retrospectively identified from the therapeutic drug monitoring (TDM) databases at 2 national epilepsy centers in Norway and Denmark (2012-2021). RESULTS Data from 165 patients (56% boys/44% girls) treated with rufinamide and 52 patients (50% boys/50% girls) treated with stiripentol were included. For rufinamide, the median age was 10 (range 2-17) years, dose 23 (3-73) mg/d, and serum concentration 34 (3-227) µmol/L [8.1 mg/L (0.71-54.0 mg/L)]. For stiripentol, the median age was 8.5 (range 1-17) years, dose 37 (18-76) mg/d, and serum concentration 33 (4-113) µmol/L [7.7 mg/L (0.93-26.3 mg/L)]. The concomitant use of 1-9 other ASMs during the data collection was noted. Pharmacokinetic variability, calculated as the concentration/(dose/kg) ratio, ranged from 0.26 to 11.31 (µmol/L)/(mg/kg) for rufinamide and 0.17-1.52 (µmol/L)/(mg/kg) for stiripentol. The intraindividual coefficients of variation ranged widely, from 5% to 110% for rufinamide and 11%-117% for stiripentol. The treatment period was at least 5 years in 50% of patients. No statistically significant effects of age, sex, or ASM comedication were observed, possibly due to the small sample size and heterogeneous groups with variable seizure situations, comorbidities, and changes in comedication and physiology. CONCLUSIONS This study demonstrates considerable pharmacokinetic variability in and between patients for both drugs and similar use in terms of age, burden of comedication and retention rates. TDM may be useful in the clinical setting to monitor and optimize treatment in this vulnerable patient group.
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Affiliation(s)
- Katrine Heger
- Department of Pharmacy, Oslo Metropolitan University, Oslo, Norway
| | | | - Marina Nikanorova
- The National Center for Epilepsy, Member of the ERN EpiCARE, Oslo University Hospital, Oslo, Norway; and
| | - Svein I Johannessen
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
- The Danish Epilepsy Center Filadelfia, Dianalund, Denmark
| | - Cecilie Johannessen Landmark
- Department of Pharmacy, Oslo Metropolitan University, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
- The Danish Epilepsy Center Filadelfia, Dianalund, Denmark
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Heger K, Kjeldstadli K, Ring N, Aaberg KM, Kjeldsen SF, Burns ML, Johannessen SI, Johannessen Landmark C. Pharmacokinetic Variability of Sulthiame: The Impact of Age, Drug-Drug Interactions, and Biochemical Markers of Toxicity in Patients with Epilepsy. Ther Drug Monit 2024; 46:237-245. [PMID: 38158595 DOI: 10.1097/ftd.0000000000001146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 07/25/2023] [Indexed: 01/03/2024]
Abstract
PURPOSE Sulthiame is an antiseizure medication increasingly used for epilepsy. The aim of this study was to investigate the pharmacokinetic variability of sulthiame in children and adults with epilepsy with respect to age, comedication, dose, serum concentration, and biochemical markers of toxicity in a clinical setting. METHOD Retrospective quantitative data from the therapeutic drug monitoring (TDM) database at the Section for Clinical Pharmacology, the National Center for Epilepsy, Norway (2015-2021), were used. RESULTS TDM data from 326 patients (127 female/199 male) were included [mean age, 11.4 (range 2-44) years; mean weight, 41 (range 14-109) kg]. Interindividual pharmacokinetic variability in the concentration/(dose/body weight) (C/(D/kg)) ratio was 16-fold; intraindividual variability was up to 8-fold (coefficient of variation = 10%-78%). Young children (younger than 6 years) had a significantly lower C/(D/kg) ratio than older age groups ( P < 0.05). Various comedications did not significantly affect the C/(D/kg) ratio, possibly owing to the small sample size. However, CYP2C19-mediated inhibition by sulthiame was indicated because patients using clobazam and sulthiame (n = 28) had a 3.5-fold higher N-desmethylclobazam C/(D/kg) ratio than those using neutral comedication (n = 45; P < 0.001). Patients with pH values below the adjusted normal range (7.32-7.42; n = 15) had a 33% higher sulthiame concentration than those with normal pH values (n = 22; P < 0.05). Blood gas measurements, especially pH, may serve as markers of toxicity and can be used in combination with clinical data when toxicity is suspected. CONCLUSIONS This study revealed the extensive intraindividual and interindividual pharmacokinetic variability of sulthiame, with age as a contributing factor. Sulthiame has clinically relevant interactions with clobazam. The use of TDM and pH as a biochemical marker may contribute to individualized and safe sulthiame treatment.
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Affiliation(s)
- Katrine Heger
- Department of Pharmacy, Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway
| | - Kari Kjeldstadli
- Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Nelly Ring
- Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Kari Modalsli Aaberg
- The National Center for Epilepsy, Sandvika, Member of the ERN EpiCare, Oslo University Hospital, Oslo, Norway; and
| | - Signe Flood Kjeldsen
- Section for Clinical Pharmacology, The National Center for Epilepsy, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Margrete Larsen Burns
- Section for Clinical Pharmacology, The National Center for Epilepsy, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Svein I Johannessen
- The National Center for Epilepsy, Sandvika, Member of the ERN EpiCare, Oslo University Hospital, Oslo, Norway; and
- Section for Clinical Pharmacology, The National Center for Epilepsy, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Cecilie Johannessen Landmark
- Department of Pharmacy, Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway
- The National Center for Epilepsy, Sandvika, Member of the ERN EpiCare, Oslo University Hospital, Oslo, Norway; and
- Section for Clinical Pharmacology, The National Center for Epilepsy, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
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Efficacy, tolerability and pharmacokinetic variability of brivaracetam in adults with difficult-to-treat epilepsy. Epilepsy Res 2022; 183:106946. [DOI: 10.1016/j.eplepsyres.2022.106946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 05/08/2022] [Accepted: 05/16/2022] [Indexed: 11/27/2022]
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Changes in the use of antiseizure medications in children and adolescents in Norway, 2009-2018. Epilepsy Res 2022; 181:106872. [DOI: 10.1016/j.eplepsyres.2022.106872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/20/2021] [Accepted: 02/03/2022] [Indexed: 11/23/2022]
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Schoonjans AS, Roosens L, Dewals W, Paelinck BP, Ceulemans B. Therapeutic drug monitoring of fenfluramine in clinical practice: Pharmacokinetic variability and impact of concomitant antiseizure medications. Epilepsia 2022; 63:686-696. [PMID: 35032026 DOI: 10.1111/epi.17162] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study was undertaken to determine the plasma concentration and pharmacokinetic variability of fenfluramine (FFA) and its main active metabolite norfenfluramine (norFFA) in relation to the prevalence of adverse effects in patients with refractory epilepsy treated with FFA. In addition, the interaction with concomitant antiseizure medications including stiripentol (STP) is studied. METHODS Patients were recruited at our center from two open-label sources, an investigator-initiated observational study and an international multicenter extension study. Venous blood samples were collected between June 2015 and December 2020. Plasma FFA and norFFA concentrations were determined by liquid chromatography tandem spectrometric analysis. Clinical data were collected retrospectively. Intrapatient coefficient of variation was calculated for all patients with at least three samples. Interpatient variability was calculated based on the concentration to weight-adjusted dose ratio (C/D) of all patients. RESULTS We collected 321 samples from 61 patients (49 with Dravet syndrome, seven with Lennox-Gastaut syndrome, and five with a developmental and epileptic encephalopathy). With a mean daily dose of .33 mg/kg/day (SD = ±.16), the median FFA plasma concentration was 41.4 µg/L (range = 5.1-712.5) and median norFFA concentration 28.1 µg/L (range = 2.6-149.6). The FFA plasma concentration was linearly related to the daily dose (p < .001) and norFFA levels (p < .001). The C/D of FFA increased with age (p < .001). Median FFA C/D was 428% higher (p < .001), norFFA C/D 83% lower (p < .001), and norFFA/FFA 23% lower (p < .001) in patients treated with STP comedication. Higher FFA concentration was associated with fatigue (p = .001) and somnolence (p < .001), but not anorexia (p = .0619) or reduction in seizure frequency (p = .772). Gender and other ASMs were not associated with significant variations in (nor)FFA C/D ratio. SIGNIFICANCE Most FFA levels are in the lower range (<50 µg/L), although a high interpatient and intrapatient variability is present. In combination with STP, the dose of FFA should be reduced.
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Affiliation(s)
- An-Sofie Schoonjans
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium.,University of Antwerp, Antwerp, Belgium
| | - Laurence Roosens
- University of Antwerp, Antwerp, Belgium.,Laboratory for TDM and Toxicology, Antwerp University Hospital, Edegem, Belgium
| | - Wendy Dewals
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium
| | | | - Berten Ceulemans
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium.,University of Antwerp, Antwerp, Belgium
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Lossius IMB, Svendsen T, Sødal HF, Kjeldstadli K, Lossius MI, Nakken KO, Johannessen Landmark C. Effect and tolerability of perampanel in patients with drug-resistant epilepsy. Epilepsy Behav 2021; 119:107965. [PMID: 33940525 DOI: 10.1016/j.yebeh.2021.107965] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Perampanel is one of the most recently approved antiseizure medications. The aim of the present study was to assess clinical efficacy and tolerability, in combination with pharmacokinetic variability, of perampanel treatment in patients at a tertiary referral center for epilepsy. METHODS We performed a retrospective observational study of patients given perampanel as adjunctive treatment in the period January 2013 - February 2019 at the National Center for Epilepsy at Oslo University Hospital, Norway. RESULTS Clinical data were available for 175 mainly adult patients with drug-resistant epilepsy with mean treatment duration of 16.1 months. We found that 23% (40 patients) were responders (i.e., achieving more than 50% reduction in seizure frequency), four of whom became seizure free, 29% (51 patients) experienced a modest effect, whereas for 29% (50 patients) perampanel had no seizure-reducing effect. A paradoxical effect, with seizure aggravation, was reported in 9% (15 patients). The responder rate was significantly higher in those with slow vs. fast dosage titration. Logistic regression analysis showed better efficacy among those with generalized vs. those with focal epilepsy. Adverse effects were reported by 135 patients (77%), ranging from mild (34%), to moderate (41%) and severe (2%). In 55 patients (41%), these adverse effects resulted in discontinuation of treatment with perampanel. The most frequent adverse effects were psychiatric symptoms (34%), dizziness (31%), and sleepiness (26%). Of the 31 patients for whom serum concentration measurements were available, the mean daily perampanel dose was 6.3 mg (SD 3.0), with a mean serum concentration at steady state of 1.03 μmol/L (range: 0.15-3.59 μmol/L). There were pronounced differences between patients, as demonstrated by a 12-fold variability in the range of concentration/dose (C/D)-ratios (0.06 to 0.69 μmol/L/mg), where enzyme inducers contributed. CONCLUSION Our results demonstrate that perampanel had a modest seizure-reducing effect in this very treatment-resistant patient group. Predictors of treatment success were generalized epilepsy and slow dosage titration. In patients without a history of psychiatric problems, clinicians could consider increasing dose of perampanel beyond 6 mg daily, taking co-medication and serum concentrations into account.
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Affiliation(s)
| | - Torleiv Svendsen
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway; Department of Neurology, Innlandet Hospital Trust, Lillehammer, Norway.
| | - Hild F Sødal
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway; Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Kari Kjeldstadli
- Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Morten Ingvar Lossius
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway; University of Oslo University, Norway
| | - Karl Otto Nakken
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway
| | - Cecile Johannessen Landmark
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway; Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway; Program for Pharmacy, Department of Life Sciences and Health, Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway
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Arfman IJ, Wammes-van der Heijden EA, Ter Horst PGJ, Lambrechts DA, Wegner I, Touw DJ. Therapeutic Drug Monitoring of Antiepileptic Drugs in Women with Epilepsy Before, During, and After Pregnancy. Clin Pharmacokinet 2021; 59:427-445. [PMID: 31912315 DOI: 10.1007/s40262-019-00845-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
During pregnancy, the pharmacokinetics of an antiepileptic drug is altered because of changes in the clearance capacity and volume of distribution. These changes may have consequences for the frequency of seizures during pregnancy and fetal exposure to antiepileptic drugs. In 2009, a review was published providing guidance for the dosing and therapeutic drug monitoring of antiepileptic drugs during pregnancy. Since that review, new drugs have been licensed and new information about existing drugs has been published. With this review, we aim to provide an updated narrative overview of changes in the pharmacokinetics of antiepileptic drugs in women during pregnancy. In addition, we aim to formulate advice for dose modification and therapeutic drug monitoring of antiepileptic drugs. We searched PubMed and the available literature on the pharmacokinetic changes of antiepileptic drugs and seizure frequency during pregnancy published between January 2007 and September 2018. During pregnancy, an increase in clearance and a decrease in the concentrations of lamotrigine, levetiracetam, oxcarbazepine's active metabolite licarbazepine, topiramate, and zonisamide were observed. Carbamazepine clearance remains unchanged during pregnancy. There is inadequate or no evidence for changes in the clearance or concentrations of clobazam and its active metabolite N-desmethylclobazam, gabapentin, lacosamide, perampanel, and valproate. Postpartum elimination rates of lamotrigine, levetiracetam, and licarbazepine resumed to pre-pregnancy values within the first few weeks after pregnancy. We advise monitoring of antiepileptic drug trough concentrations twice before pregnancy. This is the reference concentration. We also advise to consider dose adjustments guided by therapeutic drug monitoring during pregnancy if the antiepileptic drug concentration decreases 15-25% from the pre-pregnancy reference concentration, in the presence of risk factors for convulsions. If the antiepileptic drug concentration changes more than 25% compared with the reference concentration, dose adjustment is advised. Monitoring of levetiracetam, licarbazepine, lamotrigine, and topiramate is recommended during and after pregnancy. Monitoring of clobazam, N-desmethylclobazam, gabapentin, lacosamide, perampanel, and zonisamide during and after pregnancy should be considered. Because of the risk of teratogenic effects, valproate should be avoided during pregnancy. If that is impossible, monitoring of both total and unbound valproate is recommended. More research is needed on the large number of unclear pregnancy-related effects on the pharmacokinetics of antiepileptic drugs.
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Affiliation(s)
- Inge J Arfman
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | | | - Danielle A Lambrechts
- Academic Center for Epileptology Kempenhaeghe and Maastricht UMC+, Sterkselseweg 65, 5591, Heeze, VE, The Netherlands
| | - Ilse Wegner
- SEIN-Stichting Epilepsie Instellingen Nederland, Zwolle, The Netherlands
| | - Daan J Touw
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Pharmaceutical Analysis, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
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Pharmacokinetic Variability During Long-Term Therapeutic Drug Monitoring of Valproate, Clobazam, and Levetiracetam in Patients With Dravet Syndrome. Ther Drug Monit 2020; 42:744-753. [DOI: 10.1097/ftd.0000000000000781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Heger K, Lund C, Larsen Burns M, Bjørnvold M, Sætre E, Johannessen SI, Johannessen Landmark C. A retrospective review of changes and challenges in the use of antiseizure medicines in Dravet syndrome in Norway. Epilepsia Open 2020; 5:432-441. [PMID: 32913951 PMCID: PMC7469772 DOI: 10.1002/epi4.12413] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/08/2020] [Accepted: 06/13/2020] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE Dravet syndrome is a developmental and epileptic encephalopathy characterized by severe and drug-resistant seizures in early childhood, followed by developmental delay. The purpose of this study was to investigate aspects of pharmacological treatment of Norwegian patients with Dravet syndrome, focusing on the use of antiseizure medicines (ASMs) and identifying treatment challenges. METHODS Patients were identified through medical registries at the National Center for Epilepsy in Norway and National Center for Rare Epilepsy Related Disorders during 2008-2018. Additional clinical data were obtained from medical records and laboratory request forms. RESULTS We identified 53 patients with Dravet syndrome, 30/23 males/females, aged 2-50 years. The majority of patients with known seizure frequency experienced frequent seizures, 80% (n = 35/44). Only two patients were seizure-free. Valproate (n = 48), clobazam (n = 45), levetiracetam (n = 30), and stiripentol (n = 38) were most commonly used, previous or current use. More than one-third (n = 20) had tried sodium channel blockers (including lamotrigine), but these drugs were used less during the last decade. Polytherapy was common, 81% (n = 43) used two or more ASMs, and eight of these patients used 4-5 drugs (15%). Several challenges were identified: high seizure frequency, comorbidities, treatment changes with a wide range of ASMs, common use of oral gastro-tubes, extensive polypharmacy, and drug interactions. SIGNIFICANCE The use of ASMs has changed over the last decade, in accordance with updated international recommendations. Various treatment challenges were identified. This vulnerable group of patients needs close follow-up for an optimal treatment outcome.
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Affiliation(s)
- Katrine Heger
- Program for PharmacyDepartment of Life Sciences and HealthFaculty of Health SciencesOslo Metropolitan UniversityOsloNorway
| | - Caroline Lund
- Department of Rare Genetic SyndromesOslo University HospitalOsloNorway
- Department of NeurohabilitationOslo University HospitalOsloNorway
| | - Margrete Larsen Burns
- Section for Clinical PharmacologyThe National Center for EpilepsyDepartment of PharmacologyOslo University HospitalOsloNorway
| | - Marit Bjørnvold
- The National Center for EpilepsyOslo University HospitalOsloNorway
| | - Erik Sætre
- The National Center for EpilepsyOslo University HospitalOsloNorway
| | - Svein I. Johannessen
- Section for Clinical PharmacologyThe National Center for EpilepsyDepartment of PharmacologyOslo University HospitalOsloNorway
- The National Center for EpilepsyOslo University HospitalOsloNorway
| | - Cecilie Johannessen Landmark
- Program for PharmacyDepartment of Life Sciences and HealthFaculty of Health SciencesOslo Metropolitan UniversityOsloNorway
- Section for Clinical PharmacologyThe National Center for EpilepsyDepartment of PharmacologyOslo University HospitalOsloNorway
- The National Center for EpilepsyOslo University HospitalOsloNorway
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Hamilton KE, Shelton CM, Wheless J, Phelps SJ. Persistent Hypersomnolence Following Clobazam in a Child With Epilepsy and Undiagnosed CYP2C19 Polymorphism. J Pediatr Pharmacol Ther 2020; 25:320-327. [PMID: 32461746 DOI: 10.5863/1551-6776-25.4.320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We describe an 11-year-old female who presented with severe hypersomnolence after receiving 1 week of modest doses of clobazam (CLB). In reviewing the above case, we considered that the hypersomnolence could be related to a pharmacodynamic, pharmacokinetic, or pharmacogenomic issue associated with CLB or to a combination of these factors. Although serum concentrations of CLB and its active metabolite are sensitive to factors that affect cytochrome-dependent metabolism, drug-drug interactions were omitted as a cause of the hypersomnolence. Subsequent DNA analysis of the cytochrome P450 2C19 gene revealed the patient as *2/*2 genotype with poor metabolizer enzyme activity. Because genetic testing of all patients treated with CLB is currently not practical, CLB dose/concentration ratios and pharmacokinetic drug-drug interaction impact models may be indicated. Genetic testing should be considered when an adverse effect suggests the possibility of a polymorphism important to drug metabolism.
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Impact of CYP2C19 Phenotypes on Clinical Efficacy of Stiripentol in Japanese Patients With Dravet Syndrome. Ther Drug Monit 2020; 42:302-308. [DOI: 10.1097/ftd.0000000000000676] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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12
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Johannessen Landmark C, Johannessen SI, Patsalos PN. Therapeutic drug monitoring of antiepileptic drugs: current status and future prospects. Expert Opin Drug Metab Toxicol 2020; 16:227-238. [DOI: 10.1080/17425255.2020.1724956] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Cecilie Johannessen Landmark
- Program for Pharmacy, Department of Life Sciences and Health, Faculty of Health Sciences, Metropolitan University, Oslo, Norway
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway
- Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Svein I. Johannessen
- The National Center for Epilepsy, Sandvika, Oslo University Hospital, Oslo, Norway
- Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Philip N. Patsalos
- Department of Clinical & Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
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Besag FMC, Vasey MJ. An evaluation of clobazam tablets and film (AQST-120) for the treatment of Lennox-Gastaut syndrome. Expert Opin Pharmacother 2019; 20:1563-1574. [PMID: 31373526 DOI: 10.1080/14656566.2019.1642872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Lennox-Gastaut syndrome (LGS) is a chronic, epileptic encephalopathy, characterized by multiple seizure types, distinctive slow spike-wave patterns in the electroencephalogram (EEG), and severe cognitive and behavioral comorbidities. Seizures are typically refractory and long-term prognosis is poor. No antiseizure drug (ASD) is fully effective as a monotherapy. Clobazam (CLB) was licensed in the United States in 2011 as an adjunctive therapy for seizures in LGS. In 2018, a new formulation, CLB oral soluble film (COSF) (AQST-120), was approved by the Federal Drug Administration (FDA) for the same indication. Areas covered: The authors summarize current pharmacological options and guidelines for the management of seizures in LGS and efficacy and safety findings from phase II and III randomized controlled trials of adjunctive CLB in patients with LGS. An open-label extension trial is also considered. A pharmacokinetic comparison of COSF and CLB tablets is also undertaken. Expert opinion: CLB is partly effective as an add-on therapy in treating seizures in LGS. Adverse effects, pharmacokinetic interactions and the potential for tolerance with long-term treatment should be weighed against the clinical benefit when considering the introduction of CLB in this population. COSF has a similar pharmacokinetic profile to CLB tablets and may help to improve adherence to treatment.
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Affiliation(s)
- Frank M C Besag
- East London Foundation NHS Trust , Bedford , UK.,University College London , London , UK.,King's College London , London , UK
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Impact of Drug Interactions on Clobazam and N-Desmethylclobazam Concentrations in Pediatric Patients With Epilepsy. Ther Drug Monit 2018; 40:452-462. [PMID: 29746397 DOI: 10.1097/ftd.0000000000000530] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Clobazam (CLB) is approved as adjunctive treatment for seizures associated with Lennox-Gastaut syndrome in patients aged 2 years and older. It is converted to an active metabolite N-desmethylclobazam (NCLB) by CYP3A4, which is then broken down to an inactive metabolite by CYP2C19. This study characterizes the impact of CYP3A4 and CYP2C19 drug interactions on CLB and NCLB serum concentrations (Cp) and concentration/dose (Cp/D) ratios in pediatric patients with epilepsy. METHODS This was a retrospective chart review including patients older than 1 month, who received CLB between April 2012 and March 2017. Extracted data included patient demographics, CLB daily dose, CLB and NCLB Cp, calculated CLB and NCLB Cp/Cp and Cp/D ratios, and all concomitant drugs. RESULTS The study included 995 CLB concentration sets from 302 patients (median age 7.6 years and range 0.2-40.1 years). Pharmacokinetic variability was extensive, as seen by widespread ranges of CLB and NCLB Cp, NCLB/CLB Cp ratio, and 3 Cp/D ratios (CLB, NCLB, and CLB + NCLB). Comedications, described as CYP3A4 inducers and/or CYP2C19 inhibitors (carbamazepine, eslicarbazepine, felbamate, (fos)phenytoin, oxcarbazepine, pentobarbital, phenobarbital, rufinamide, and topiramate), generally increased NCLB/CLB Cp ratio (267%-400%), NCLB Cp/D ratio (167%-202%), and CLB + NCLB Cp/D ratio (142%-185%) and decreased CLB Cp/D ratio (47%-76%) compared with a group of concentration sets in patients receiving only neutral comedications (P < 0.025 for all comparisons). Older age was associated with higher Cp/D ratios (mg/kg), indicative of decreased clearance. CONCLUSIONS Pharmacokinetic variability of CLB in pediatric patients is extensive, and it is influenced by drug-drug interactions and age. Therapeutic drug monitoring of CLB and active metabolite NCLB with calculation of various Cp/Cp and Cp/D ratios can provide useful insight into CLB pharmacokinetics and help differentiate between causes of variability.
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Heller AH, Wargacki S, Jung C, Buan CV, Wyatt DJ, Schobel AM. Pharmacokinetics of clobazam oral soluble film. Epilepsia 2018; 59:2153-2161. [PMID: 30357823 DOI: 10.1111/epi.14581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/21/2018] [Accepted: 09/21/2018] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Clobazam oral soluble film (COSF) is a novel dosage form under development for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome. The present study was undertaken to assess the pharmacokinetics of clobazam administered as single doses of COSF 20 and 10 mg compared with clobazam tablets (CTAB) 20 and 10 mg in healthy adults. A secondary objective was to assess the safety and tolerability of single doses of COSF 20 and 10 mg. METHODS A total of 51 adult volunteers were enrolled in a single-dose, open-label, randomized four-sequence, four-period, crossover study with treatments (A) COSF 20 mg, (B) CTAB 20 mg, (C) COSF 10 mg, and (D) CTAB 10 mg. Pharmacokinetic sampling for clobazam and N-desmethylclobazam was carried out until 21 days postdose with a 28-day washout. Subjects were monitored for adverse events (AEs) throughout the study. Visual inspections of the administration site were performed before and after COSF administration to monitor for mucosal irritation. RESULTS COSF at single doses of 10 and 20 mg was bioequivalent to CTAB at equivalent doses for both clobazam and its active metabolite N-desmethylclobazam. The pharmacokinetics of both formulations was dose-proportional at doses of 10 and 20 mg. The number of AEs and the number of subjects experiencing AEs were dose-related across the treatment groups, with somnolence the most common event. None of these events was severe or serious, and most were mild. There was no evidence for local irritation at the administration site following COSF. SIGNIFICANCE COSF is a novel clobazam dosage form that is bioequivalent to CTAB. Because of its ease of administration, COSF may be expected to improve adherence, reduce likelihood of dosing error, and provide more accurate dosing than formulations of clobazam that are currently available.
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Affiliation(s)
| | | | - Cassie Jung
- Aquestive Therapeutics, Inc, Warren, New Jersey
| | | | - David J Wyatt
- Syneos Health Clinical Solutions, Early Phase, Miami, Florida
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Reimers A, Berg JA, Burns ML, Brodtkorb E, Johannessen SI, Johannessen Landmark C. Reference ranges for antiepileptic drugs revisited: a practical approach to establish national guidelines. Drug Des Devel Ther 2018; 12:271-280. [PMID: 29467570 PMCID: PMC5811172 DOI: 10.2147/dddt.s154388] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND OBJECTIVE Laboratories sometimes use different reference ranges for the same antiepileptic drug (AED), particularly for new and poorly investigated drugs. This may contribute to misunderstandings, concerns or inappropriate dose changes, which in turn may affect therapeutic effect, drug safety or treatment adherence. Therefore, the Norwegian Association of Clinical Pharmacology wished to update and harmonize the reference ranges for AEDs and establish national guidelines for Norway. METHODS A working group collected information on the reference ranges used by Norwegian laboratories for all commonly used AEDs. These reference ranges were compared to recent recommendations by the International League Against Epilepsy, current literature, applicable clinical studies, reference ranges used by leading Northern European epilepsy centers outside of Norway, and routine data derived from Norwegian laboratory databases. RESULTS Reference ranges varied between laboratories for four of 23 available AEDs (lamotrigine, valproate, eslicarbazepine and oxcarbazepine). For four AEDs (brivaracetam, perampanel, stiripentol and sulthiame), reference ranges had not previously been established. In total, 13 reference ranges were either harmonized, updated or newly established. No changes were applied to the remaining 10 AEDs. CONCLUSION Updated and harmonized reference ranges are now available for 22 of the 23 AEDs available in Norway. The exception is vigabatrin (reference range not applicable). Revision of reference ranges is an important part of pharmacovigilance of AEDs and must be a continuous process based on current literature and clinical experience.
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Affiliation(s)
- Arne Reimers
- Department of Clinical Pharmacology, St Olavs University Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jon Andsnes Berg
- Laboratory of Clinical Biochemistry, Section of Clinical Pharmacology, Haukeland University Hospital, Bergen, Norway
| | - Margrete Larsen Burns
- Department of Pharmacology, Section for Clinical Pharmacology, The National Center for Epilepsy, Oslo University Hospital, Oslo, Norway
| | - Eylert Brodtkorb
- Department of Neurology and Clinical Neurophysiology, St Olavs University Hospital, Trondheim, Norway
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Svein I Johannessen
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
- The National Center for Epilepsy, Oslo University Hospital, Oslo, Norway
| | - Cecilie Johannessen Landmark
- Department of Pharmacology, Section for Clinical Pharmacology, The National Center for Epilepsy, Oslo University Hospital, Oslo, Norway
- The National Center for Epilepsy, Oslo University Hospital, Oslo, Norway
- Programme for Pharmacy, Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway
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Stefanović S, Janković SM, Novaković M, Milosavljević M, Folić M. Pharmacodynamics and common drug-drug interactions of the third-generation antiepileptic drugs. Expert Opin Drug Metab Toxicol 2017; 14:153-159. [PMID: 29268032 DOI: 10.1080/17425255.2018.1421172] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Anticonvulsants that belong to the third generation are considered as 'newer' antiepileptic drugs, including: eslicarbazepine acetate, lacosamide, perampanel, brivaracetam, rufinamide and stiripentol. Areas covered: This article reviews pharmacodynamics (i.e. mechanisms of action) and clinically relevant drug-drug interactions of the third-generation antiepileptic drugs. Expert opinion: Newer antiepileptic drugs have mechanisms of action which are not shared with the first and the second generation anticonvulsants, like inhibition of neurotransmitters release, blocking receptors for excitatory amino acids and new ways of sodium channel inactivation. New mechanisms of action increase chances of controlling forms of epilepsy resistant to older anticonvulsants. Important advantage of the third-generation anticonvulsants could be their little propensity for interactions with both antiepileptic and other drugs observed until now, making prescribing much easier and safer. However, this may change with new studies specifically designed to discover drug-drug interactions. Although the third-generation antiepileptic drugs enlarged therapeutic palette against epilepsy, 20-30% of patients with epilepsy is still treatment-resistant and need new pharmacological approach. There is great need to explore all molecular targets that may directly or indirectly be involved in generation of seizures, so a number of candidate compounds for even newer anticonvulsants could be generated.
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Affiliation(s)
- Srđan Stefanović
- a Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
| | - Slobodan M Janković
- a Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
| | - Milan Novaković
- a Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
| | - Marko Milosavljević
- a Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
| | - Marko Folić
- a Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
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The Impact of Pharmacokinetic Interactions With Eslicarbazepine Acetate Versus Oxcarbazepine and Carbamazepine in Clinical Practice. Ther Drug Monit 2017; 38:499-505. [PMID: 27414974 DOI: 10.1097/ftd.0000000000000306] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Eslicarbazepine acetate (ESL) is a new anti-epileptic drug (AED) chemically related to oxcarbazepine (OXC) and carbamazepine (CBZ) and is increasingly used in clinical practice. The purpose of the study was to investigate 2-way pharmacokinetic interactions between ESL and other AEDs as compared to OXC and CBZ. METHODS Anonymous data regarding age, gender, use of AEDs, daily doses and serum concentration measurements of ESL, OXC, CBZ and lamotrigine (LTG) and other AEDs were retrieved from 2 therapeutic drug monitoring (TDM) databases in Norway. Drugs were categorized according to their known potential for interactions. Concentration/dose (C/D) ratios were calculated. RESULTS Data from 1100 patients were available. The C/D ratios of ESL and OXC were unchanged in combination with enzyme-inducing AEDs or valproate (VPA). The C/D ratio of CBZ decreased by 40% and 22% in combination with other enzyme-inducing AEDs or VPA, respectively, pointing to an increased clearance. ESL demonstrated no significant enzyme-inducing effect on LTG metabolism although there was a 20% and 34% decrease in the C/D ratio of LTG in combination with OXC and CBZ, respectively. CONCLUSIONS Possible pharmacokinetic interactions have been studied for ESL as compared to OXC and CBZ. The pharmacokinetics of ESL is not affected by enzyme-inducing AEDs or VPA and does not affect the metabolism of LTG in contrast to OXC and CBZ. The study demonstrates the value of using TDM databases to explore the potential for pharmacokinetic interactions of new AEDs.
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Svendsen T, Brodtkorb E, Baftiu A, Burns ML, Johannessen SI, Johannessen Landmark C. Therapeutic Drug Monitoring of Lacosamide in Norway: Focus on Pharmacokinetic Variability, Efficacy and Tolerability. Neurochem Res 2017; 42:2077-2083. [DOI: 10.1007/s11064-017-2234-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 10/19/2022]
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Chen J, Hu Y, Lu Q, Wang P, Zhan H. Determination of proflavine in rat whole blood without sample pretreatment by laser desorption postionization mass spectrometry. Anal Bioanal Chem 2017; 409:2813-2819. [PMID: 28188352 DOI: 10.1007/s00216-017-0225-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/19/2017] [Accepted: 01/24/2017] [Indexed: 11/28/2022]
Abstract
A novel pretreatment-free method involving laser desorption postionization (LDPI) coupled with time-of-flight mass spectrometry (MS) was developed for the monitoring of proflavine level in rat whole blood. It comprises a protocol for dosing via intravenous administration and collection of whole blood, followed by direct LDPI-MS analysis without any sample pretreatment. An intense ion signal at m/z 209 was observed from whole blood without any interference signals, except some background signals below m/z 100. The calibration curve was established with use of 9-phenylacridine as the internal standard for proflavine determination from the plotting of the peak ratios of proflavine to the internal standard, with a correlation coefficient (R 2) greater than 0.99. The limit of detection was estimated to be 0.48 pmol/mm2 and the quantification range was 0.5-16.5 μg/mL for proflavine. In addition, only a minimal matrix effect was observed, as expected from considerations of the desorption and ionization mechanism. Interday and intraday accuracy and precision were calculated to be within 13% and 82-114%, respectively. Estimated concentrations of proflavine residue in whole blood were also successfully obtained at selected time points after dosing. The proposed method is simple, low cost, and sensitive, and should be seen as a complementary method for monitoring drug levels in blood. Graphical Abstract Monitoring proflavine levels in rat whole blood at different time points using laser desorption postionization mass spectrometry (LDPI-MS).
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Affiliation(s)
- Jiaxin Chen
- MOE Key laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, 510631, China
| | - Yongjun Hu
- MOE Key laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, 510631, China.
| | - Qiao Lu
- MOE Key laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, 510631, China
| | - Pengchao Wang
- MOE Key laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, 510631, China
| | - Huaqi Zhan
- MOE Key laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, 510631, China
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Pharmacokinetic variability, efficacy and tolerability of eslicarbazepine acetate-A national approach to the evaluation of therapeutic drug monitoring data and clinical outcome. Epilepsy Res 2016; 129:125-131. [PMID: 28043062 DOI: 10.1016/j.eplepsyres.2016.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/29/2016] [Accepted: 12/03/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Eslicarbazepine acetate (ESL) is a new antiepileptic drug (AED), still insufficiently studied regarding pharmacokinetic variability, efficacy and tolerability. The purpose of this study was to evaluate therapeutic drug monitoring (TDM) data in Norway and relate pharmacokinetic variability to clinical efficacy and tolerability in a long-term clinical setting in patients with refractory epilepsy. METHODS This retrospective observational study included TDM-data from the main laboratories and population data from the Norwegian Prescription Database in Norway, in addition to clinical data from medical records of adult patients using ESL for up to three years, whenever possible. RESULTS TDM-data from 168 patients were utilized for assessment of pharmacokinetic variability, consisting of 71% of the total number of patients in Norway using ESL, 2011-14. Median daily dose of ESL was 800mg (range 400-1600mg), and median serum concentration of ESL was 53μmol/L (range 13-132μmol/L). Inter-patient variability of ESL was extensive, with 25-fold variability in concentration/dose ratios. Additional clinical data were available from 104 adult patients out of the 168, all with drug resistant focal epilepsy. After 1, 2 and 3 years follow-up, the retention rate of ESL was 83%, 72% and 64%, respectively. ESL was generally well tolerated as add-on treatment, but sedation, cognitive impairment and hyponatremia were reported. Hyponatremia (sodium <137mmol/L) was present in 36% of the patients, and lead to discontinuation in three. CONCLUSION Pharmacokinetic variability of ESL was extensive and the demonstration of usefulness of TDM requires further studies. In patients with drug resistant focal Epilepsy, the high retention rate indicated good efficacy and tolerability. Hyponatremia was observed in one third of the patients. The present results point to a need for individualization of treatment and TDM may be useful.
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