In a study with 113 Asian children in which phenobarbitone was used as the sole antiepileptic drug in 75 children, including Chinese, Malays, and Indians, the mean phenobarbitone dosage required to produce a plasma level of 15 micrograms/ml was 5.2 mg/kg/day. While the mean plasma level/dose ratio varied, the differences between the three ethnic groups were not statistically significant. Also of little difference were the ratios between the male and female groups. For those patients with poor seizure control, however, the mean plasma level/dose ratio was significantly lower than in those whose seizures were controlled. Using additional anticonvulsant drugs concurrently with phenobarbitone in 40 children raised the mean plasma level/dose ratios significantly in each ethnic group. Further, the greater age level in those given additional antiepileptic drugs might have contributed slightly to a higher mean plasma level/dose ratio.
We estimated individual and population Michaelis-Menten pharmacokinetic parameters for phenytoin (DPH) in epileptic patients attending our neurology clinic using the computer programme. OPT. Our results agreed well with literature values but were lower than those we obtained earlier in a smaller number of patients. The Km was independent of age, weight and sex but there was a weak, correlation between Vm and body weight. We conclude that the use of population Vm and Km in normograms could lead to errors in DPH dose estimations as they correlated very poorly with patient characteristics. OPT was easy to use and sufficiently accurate for deriving dose estimates in routine patients. Its use would enable practitioners to generate their patients' own parameters for use in individual dosage adjustments. The estimates can subsequently be updated as more data become available.
This was a descriptive study to assess parents' knowledge of epilepsy in their children at the Klinik Pakar Pediatrik in Universiti Kebangsaan Malaysia from 1.1.93-31.6.93. Factors that influence the level of knowledge were examined. Our hypothesis was that the level of knowledge was low and level of education and social factors were important. Fifty consecutive parents were interviewed during the clinic appointments. The questionnaire consisted of 25 questions which had been used in a survey on epilepsy in Australia. In order to cater for the local population the questions were modified by adding new questions pertaining to local situation. The results showed that 90% (45/50) of parents were unaware of the type of epilepsy their children were suffering from. 50% (25/50) of parents knew the underlying cause of epilepsy of which 32% (8/25) attributed it to brain disease, 8% (2/25) to birth defects and 10% (3/25) to fever. Factors such as duration of epilepsy, parental education and racial differences between Malay and other races (Chinese, Indians) did not reach any statistical significance (p > 0.05). 80% of patients (30/50) were on monotherapy. However, 90% (45/50) of parents were unaware of their children's medications. 82% of parents (31/50) knew that the anti-convulsants would only control their children's convulsions. Only 10% (8/50) of parents knew the acute management of seizures. Wrong practices such as inserting spoons (5/50) or massaging their limbs (17/50) during an acute attack were still common. 70% of parents (35/50) attended the follow-up clinics hoping that their children's epilepsy would be cured. Parents with low economic status and of children with duration of epilepsy of less than five years had been coming to the clinic regularly. (p = 0.01 and p = 0.02 respectively). In conclusion, the overall knowledge of these parents was poor. In order to improve the management of epilepsy, it is necessary to educate parents with reading materials and effective educational packages.
Study site: Paediatric clinic, Institut Pediatrik, Kuala Lumpur, Malaysia
An observational study of all children with intractable epilepsy at the Paediatric Institute prescribed Lamotrigine as an add-on therapy between January 1994 and November 1998 was conducted. A total of 30 children were recruited. Three had adverse effects to the drug and it was withdrawn. Of the remaining 27, there were 20 boys and 7 girls, ranging from 2 to 17 years. Fifteen children had generalised epilepsy, 6 had partial epilepsy, 2 had West syndrome and 4 had Lennox Gastaut syndrome. Six children (20%) became seizure free, and 14 (54%) had a greater than 50% reduction in seizure frequency. However 7 children (23%) did not respond and 3 experienced a deterioration in seizure severity. Nine children were noted to have an improvement in alertness and behaviour. Our small series suggests that Lamotrigine is useful as add-on therapy in childhood intractable epilepsy.
OBJECTIVE: (1) To determine the effect of lamotrigine add-on therapy on the seizure frequency and cost in paediatric patients. (2) To determine the prescribing pattern of other antiepileptic drugs (AEDs).
METHOD: A retrospective study of medical records was carried out from October 2000 to June 2001 at the paediatric clinic, Hospital Pulau Pinang.
MAIN OUTCOME MEASURE: Seizure frequency, cost of drug and types of AED prescribed.
RESULTS: A total of 209 medical records were retrieved during the study period. Lamotrigine (LTG) was prescribed in 29 patients as add-on therapy. In 18 patients, there was a significant reduction in seizure frequency after the addition of LTG. Approximately 70% experienced a reduction in seizure frequency of more than 50%. Side effects of LTG were considered mild and manageable. However, drug cost after the addition of LTG increased by 103%. In the remaining 180 patients, the most common AED prescribed was sodium valproate (VPA). Only 15% of the patients received combination therapy. Mean monthly cost of monotherapy was found to be RM 24.4 while monthly cost of combination therapy was RM 45.4 (1 Euro-RM 5.00).
CONCLUSION: The majority of paediatric patients in the study are on AED monotherapy and only a small percentage was prescribed lamotrigine. The use of lamotrigine is associated with better seizure control but with an increase in drug cost.
Study site: paediatric clinic, Hospital Pulau Pinang.
This middle aged Malaysian man presented complaining of painful gums for a few months. He is known to have had epilepsy since childhood.
Keywords: quiz; gum hypertrophy
The C3435T, a major allelic variant of the ABCB1 gene, is proposed to play a crucial role in drug-resistance in epilepsy. The C/C genotype carriers reportedly are at higher risk of pharmacoresistance to AEDs, but only in some studies. The hypothesis of the C-variant associated risk and resistance to antiepileptic drugs (AEDs) has been hampered by conflicting results from inadequate power in case-control studies. To assess the role of C3435T polymorphism in drug-resistance in epilepsy, a systematic review and meta-analysis was conducted.
Over-expression of P-glycoprotein, encoded by the ABCB1 gene, is proposed to be involved in resistance to antiepileptic drugs in about 30% of patients with epilepsy. Here, we investigated the possible association between ABCB1 polymorphisms and sodium valproate (VPA) treatment in Malaysian epilepsy patients. Genotypes were assessed in 249 drug-resistant and 256 drug-responsive Malaysian patients for C1236T, G2677T/A, and C 5T polymorphisms in the ABCB1 gene. No genotypes, alleles, or haplotypes were associated with the response to VPA in either the overall group or Chinese, Indian, and Malay subgroups. Our data suggest that C1236T, G2677T/A, and C3435T polymorphisms in the ABCB1 gene do not contribute to the response to VPA in patients with epilepsy.
Several studies demonstrated a link between ABCB1 gene variants and the response to treatment in epilepsy, but the results have been inconclusive. Here, we performed the first haplotype meta-analysis to examine the association of haplotypes of ABCB1 common variants with the response to treatment in epilepsy.
It is proposed that overexpression of P-glycoprotein (P-gp), encoded by the ABC subfamily B member 1 (ABCB1) gene, is involved in resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation and haplotype patterns are population specific which may cause different phenotypes such as response to AEDs. Although several studies examined the link between the common polymorphisms in the ABCB1 gene with resistance to AEDs, the results have been conflicting. This controversy may be caused by the effect of some confounders such as ethnicity and polytherapy. Moreover, expression of the ABCB1 gene is under the control of pregnane X receptor (PXR). Evidence showed that PXR gene contribute to the response to treatment. The aim of this study was to assess the association of ABCB1 and PXR genetic polymorphisms with response to the carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in epilepsy. Genotypes were assessed in 685 Chinese, Indian, and Malay epilepsy patients for ABCB1 (C1236T, G2677T, C3435T) and PXR (G7635A) polymorphisms. No association between these polymorphisms and their haplotypes, and interaction between them, with response to treatment was observed in the overall group or in the Chinese, Indian, and Malay subgroups. Our data showed that these polymorphisms may not contribute to the response to CBZ or VPA monotherapy treatment in epilepsy.
We describe the association of the HLA-B*1502 allele in 27 epilepsy patients (19 Malays, 8 Chinese) treated with carbamazepine (CBZ) at the UKM Medical Center (UKMMC), 6 with CBZ-Steven Johnson Syndrome (CBZ-SJS), 11 with CBZ-induced rash, 2 with suspected phenytoin-induced rash and 8 negative controls. Our study showed that 10 (6 Malay, 4 Chinese) patients were positive for HLA-B*1502. Out of the 10 patients, six were confirmed to have CBZ-SJS (p = 0.0006), while four patients developed a skin rash. However there were 6 Malay patients and 1 Chinese patient that developed a skin rash after CBZ administration who were not positive for the allele, indicating that there might be more that one allele associated with CBZ-induced hypersensitivity. Another 2 patients were suspected of having phenytoin-induced rash, instead of CBZ, and these patients did not have HLA-B*1502. In conclusion, this study confirmed the association of HLA-B*1502 with CBZ-SJS among Malaysian epilepsy patients, however there might be other genes that could be responsible for the CBZ-induced rash.
Approximately one third of newly treated epilepsy patients do not respond to antiepileptic drugs (AEDs). Overexpression of P-glycoprotein (P-gp) efflux transporter has been proposed to have a critical role in causing resistance to AEDs. P-gp is a product of the ATP-binding cassette subfamily B member 1 (ABCB1) gene. The purpose of this study was to investigate a possible link between ABCB1 rs3789243 C>T, C1236T, G2677T/A, rs6949448 C>T, and C3435T haplotypes with response to carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in Malaysian epilepsy patients. No ABCB1 haplotype association was found with response to either CBZ or VPA monotherapy in the Chinese, Indian, and Malay patients. C3435 allele carriers of the Indian males with cryptogenic epilepsy were more prone to resistance to either CBZ or VPA than carriers of T allele. Moreover, rs3789243T allele carriers of Malay females with symptomatic epilepsy were more resistant to either CBZ or VPA than C allele carriers. Our findings suggest that the ABCB1 rs3789243 C>T, C1236T, G2677T/A, rs6949448 C>T, and C3435T haplotypes do not contribute to response to AED treatment in epilepsy.
Approximately 30% of epilepsy patients do not response to antiepileptic drugs (AEDs). The functional SCN1A IVS5N+5 polymorphism may play a role in response to some AEDs. The purpose of this study was to examine this hypothesis in a cohort study of Malaysian and Hong Kong Chinese epilepsy patients on sodium valproate (VPA) monotherapy and in a meta-analysis.
Studies on the impact of epilepsy on employment have been extensively performed in European and some Asian countries but not in Southeast Asia such as Malaysia, a country with a robust economy, low unemployment rate, and minimal social security benefits for the unemployed. This study aims to determine the impact of epilepsy on employment in Malaysia.
OBJECTIVES: To assess the practices associated with the application of therapeutic drug monitoring (TDM) for antiepileptic drugs (AEDs) in the management of children with structural-metabolic epilepsy.
METHODS: It was a retrospective chart review and included children aged ≥2 years old with structural-metabolic epilepsy, treated with AEDs, and received TDM. The data were extracted from the medical records.
RESULTS: Thirty-two patients were identified with 50 TDM assays. In two thirds of the assays, "check level" and "recheck level" were the reasons behind the requesting of serum level monitoring of AEDs. Knowledge of serum AED levels led to alterations in the management in 60% of the assays. Thirty-two (76%) pediatrician's actions were consistent with the recommendation of TDM pharmacist. Forty-nine (98%) levels were appropriately indicated. In relation to the appropriateness of sampling time, 9 (18%) levels were not assessed due to missing data. Twenty-seven (54%) levels were appropriately sampled.
CONCLUSIONS: More studies should be designed to improve the component of the current TDM request form, especially in the reason section. By the same token, the number of pointless assays and the costs to the health care system can be reduced both by enhancing and improving the educational standards of the requesting neurologists.
KEYWORDS: Malaysia; epilepsy; neurology; pediatrics; therapeutic drug monitoring
Study site: Paediatric Neurology Clinic, Hospital Pulau Pinang, Malaysia
Aim: Approximately a third of newly diagnosed epilepsy patients do not respond to antiepileptic drugs (AEDs). Evidence suggests that low penetrance variants in the genes of drug targets such as voltage-gated sodium channels may be involved in drug responsiveness. To examine this hypothesis, we compared data from two epilepsy cohorts from Malaysia and Hong Kong, as well as a meta-analysis from published data.
Materials & methods: Genotype analysis of 39 polymorphisms located in the SCN1A, SCN2A and SCN3A genes was performed on 1504 epilepsy patients from Malaysia and Hong Kong who were receiving AEDs. Meta-analysis was performed for pooled data of SCN1A rs3812718 and rs2298771, and SCN2A rs17183814 polymorphisms.
Results: Our data from the Hong Kong and Malaysia cohorts showed no significant allele, genotype and haplotype association of polymorphisms in the SCN1A, SCN2A, and SCN3A genes with drug responsiveness in epilepsy. This finding was supported by a meta-analysis for SCN1A rs3812718 and rs2298771, and for SCN2A rs17183814 polymorphisms.
Conclusion: Our comprehensive study suggests that common polymorphisms in SCN1A, SCN2A and SCN3A do not play major roles in influencing response to AEDs.
The authors describe a case of a 37-year-old Malay lady with an unusually slow carbamazepine clearance, which may be related to genetic polymorphisms of drug metabolizing enzymes and transporters. When given a small daily dose of 200 mg immediate-release carbamazepine, this patient experienced drowsiness. Subsequently, she reduced her carbamazepine dose to 200 mg twice a week (on Mondays and Fridays), resulting in poor seizure control. At the same time, the patient was diagnosed with hyperthyroidism and was given carbimazole and propranolol. Hyperthyroidism and the concurrent use of these antihyperthyroid agents may have further slowed down the metabolism of carbamazepine. Therapeutic drug monitoring of carbamazepine was carried out, and a slow carbamazepine clearance of 1.45 L·h⁻¹ per 70 kg was observed. Genotyping of selected genetic variants in CYP3A4, CYP3A5, EPHX1, ABCB1, and ABCC2 revealed that she has CYP3A5*3/*3 and ABCB1 3435-CC genotypes. Both genotypes have been shown to be associated with higher adjusted mean serum carbamazepine concentration in Chinese and Korean patients with epilepsy. Physicians should be vigilant about the risk of adverse effects among patients with a slow carbamazepine clearance, especially in Malays. Simulations of carbamazepine dosing regimen based on the pharmacokinetic parameters of this patient were performed to allow individualization of drug therapy.
To investigate cross-sectional and longitudinal differences in static and dynamic standing balance measures and lower limb muscle strength in patients who are treated chronically with antiepileptic drugs (AEDs).