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  1. Miyata-Nozaka Y, Tan HJ, Wong SW, Raymond AA, Omar H, Zain SM
    Int J Clin Pharmacol Ther, 2021 Jan;59(1):8-16.
    PMID: 33026315 DOI: 10.5414/CP203761
    OBJECTIVE: Epilepsy is a common chronic neurological condition characterized by recurrent seizures. Approximately 30 - 40% of epileptic patients do not respond to antiepileptic drugs. Previous studies suggest that CYP3A5 polymorphisms affect carbamazepine metabolism.

    MATERIALS AND METHODS: To examine this hypothesis, in the present study, the associations between CYP3A5 variants (rs776746 and rs1419745) and response to carbamazepine and valproic acid monotherapy in Malaysian epileptic patients were evaluated.

    RESULTS: A total of 288 Malaysian epileptic patients were recruited and further reviewed, of whom 63 patients were on carbamazepine monotherapy, and 85 patients were on valproic acid monotherapy. There was no patient with drug hypersensitivity syndrome within the population. Subjects were genotyped by using Sequenom MassARRAY platform. This study found a significant association of CYP3A5 rs776746 with the carbamazepine treatment response in total patients (p = 0.026) and Malay ethnic subgroup (p = 0.006). In addition, a marginal significant association of CYP3A5 rs1419745 with carbamazepine treatment response was reported in the Malays. Similarly, CYP3A5 rs776746 was associated with valproic acid response in total patients (p = 0.037) and Malays (marginal p = 0.05).

    CONCLUSION: Our findings suggest that CYP3A5 polymorphisms affect carbamazepine and valproic acid response in Malaysian epileptic patients.

    Matched MeSH terms: Carbamazepine/therapeutic use
  2. Shaikh S, Yaacob HB, Abd Rahman RB
    J Chin Med Assoc, 2011 Jun;74(6):243-9.
    PMID: 21621166 DOI: 10.1016/j.jcma.2011.04.002
    BACKGROUND: Anticonvulsants are regarded as useful for the treatment of neuropathic pain. In this study, we evaluated the efficacy and occurrence of side effects of lamotrigine (LTG) in comparison with carbamazepine (CBZ), in trigeminal neuralgia (TN) patients.

    METHODS: The study was an interventional and crossover comparison. Twenty-one patients with TN were administered with LTG in comparison to CBZ. The clinical trials comprised two phases of 40 days each, with an intervening three-day washout period. The final titration in dose for LTG was 400 mg and 1,200 mg for CBZ. Efficacy of the medications involved was determined by visual analog scale (VAS) and verbal rating scale (VRS). Side effects were recorded through marking of the profiles of side effects encountered on administration of LTG and CBZ, together with baseline haematological, hepatic and renal investigations.

    RESULTS: Both on VAS and VRS assessments, in terms of proportion of patients, CBZ benefitted 90.5% (19/21) of the patients with pain relief (p  0.05). Meanwhile, LTG inflicted 14% (3/21) of the patients with haematological, hepatic and renal derangements, as compared with 48% (10/21) on CBZ.

    CONCLUSION: LTG is generally an effective and safe treatment for management of TN, compared to CBZ.

    Matched MeSH terms: Carbamazepine/therapeutic use*
  3. Chong HY, Lim KS, Fong SL, Shabaruddin FH, Dahlui M, Mei Lai PS, et al.
    Br J Clin Pharmacol, 2023 Nov;89(11):3340-3351.
    PMID: 37294011 DOI: 10.1111/bcp.15818
    AIMS: Despite the availability of newer antiseizure medications, carbamazepine (CBZ) remains the gold standard. However, patients of Asian ancestry are susceptible to CBZ-related severe cutaneous adverse reactions. Universal HLA-B*15:02 screening is a promising intervention to address this. With the increasing recognition of integrating real-world evidence in economic evaluations, the cost-effectiveness of universal HLA-B*15:02 screening was assessed using available real-world data in Malaysia.

    METHODS: A hybrid model of a decision tree and Markov model was developed to evaluate 3 strategies for treating newly diagnosed epilepsy among adults: (i) CBZ initiation without HLA-B*15:02 screening (current practice); (ii) universal HLA-B*15:02 screening prior to CBZ initiation; and (iii) alternative prescribing without HLA-B*15:02 screening. The model was populated with real-world inputs derived from the Malaysian population. From a societal perspective, base-case analysis and sensitivity analyses estimated the costs and outcomes over a lifetime. Incremental cost-effectiveness ratios were calculated.

    RESULTS: In the base-cases analysis, universal HLA-B*15:02 screening yielded the lowest total costs and the highest total quality-adjusted life years (QALYs) gained. Compared with current practice, universal screening was less costly by USD100 and more effective by QALYs increase of 0.1306, while alternative prescribing resulted in 0.1383 QALYs loss at additional costs of USD332. The highest seizure remission rate (56%) was estimated for universal HLA-B*15:02 screening vs. current practice (54%) and alternative prescribing (48%).

    CONCLUSION: Our study suggests that universal HLA-B*15:02 screening is a cost-effective intervention in Malaysia. With the demonstrated value of real-world evidence in economic evaluations, more relevant standardization efforts should be emphasized to better inform decision-making.

    Matched MeSH terms: Carbamazepine/therapeutic use
  4. Subenthiran S, Abdullah NR, Muniandy PK, Joseph JP, Cheong KC, Ismail Z, et al.
    Genet. Mol. Res., 2013;12(4):5937-44.
    PMID: 24338387 DOI: 10.4238/2013.November.26.3
    Carbamazepine (CBZ) is used as the first line of treatment of complex partial seizures (CPS) in Malaysia. While this drug is known to be effective for the treatment of CPS, more than 30% of patients remain drug resistant to CBZ mono-therapy. We examined a possible relationship between patients' response to CBZ mono-therapy and the G2677T SNP of the ABCB1 gene. Three hundred and fourteen patients with CPS were recruited from the Neurology Department of the Kuala Lumpur Hospital, of whom 152 were responders and the other 162 were non-responders to CBZ mono-therapy. DNA was extracted from blood samples and real-time PCR was performed to detect the G2677T SNP of the ABCB1 gene. Results were described as genotype frequencies and compared by logistic regression analysis. Among the 152 responders, 74% had the GG genotype. However, among the 162 non-responders, 26.5% had the GT genotype and 39% had the TT genotype. There was a significant difference in genotype frequency (TT vs GG; odds ratio 4.70; 95% confidence interval, 2.70-8.20) between responders and non-responders. The presence of the T allele of the G2677T SNP appears to be a useful screening marker to determine if a patient is going to be resistant to CBZ as a single drug therapy in the treatment of CPS.
    Matched MeSH terms: Carbamazepine/therapeutic use*
  5. Subenthiran S, Abdullah NR, Joseph JP, Muniandy PK, Mok BT, Kee CC, et al.
    PLoS One, 2013;8(5):e64827.
    PMID: 23717663 DOI: 10.1371/journal.pone.0064827
    Carbamazepine (CBZ) is used as the first line of treatment of Complex Partial Seizures (CPS) in the Epilepsy Clinic, Neurology Department of Kuala Lumpur Hospital (KLH). More than 30% of the patients remain drug resistant to CBZ mono-therapy. CBZ is transported by the P-glycoprotein (P-gp). The P-gp encoded by the ABCB1 and ABCC2 genes are expressed in drug resistant patients with epilepsy. A few studies have shown significant association between CBZ resistant epilepsy and Linkage Disequilibrium (LD) with adjacent polymorphisms of these genes. Our study is aimed at determining the correlation between patients' response to CBZ mono-therapy to Single Nucleotide Polymorphisms G2677T and C3435T of the ABCB1 gene as well as G1249A and -24C>T of the ABCC2 gene.
    Matched MeSH terms: Carbamazepine/therapeutic use*
  6. Haerian BS, Lim KS, Mohamed EH, Tan HJ, Tan CT, Raymond AA, et al.
    Seizure, 2011 Sep;20(7):546-53.
    PMID: 21530324 DOI: 10.1016/j.seizure.2011.04.003
    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.
    Matched MeSH terms: Carbamazepine/therapeutic use
  7. Norlinah MI, Shahizon AM
    Med J Malaysia, 2008 Dec;63(5):410-2.
    PMID: 19803303 MyJurnal
    Secondary paroxysmal dyskinesias (PxD) have been previously reported in patients with multiple sclerosis, lacunar infarcts, head trauma, metabolic disorders such as hyperglycaemia, hypocalcaemia, migraine and central nervous system (CNS) infections. The causative lesions typically involve the basal ganglia structures, medulla and rarely the spinal cord. We report two patients who presented with paroxysmal dyskinesias as the only manifestation of subcortical white-matter ischaemia. Patient 1 presented with 3-year history of paroxysmal kinesigenic dyskinesia (PKD) and patient 2 with 6-month history of paroxysmal nonkinesigenic dyskinesia (PNKD). All investigations, including CSF oligoclonal bands were negative, except for a brain MRI which showed multiple, non-enhancing subcortical white matter lacunar infarcts. Therefore, subcortical white matter ischaemia should also be included in the differential diagnosis of PxD.
    Matched MeSH terms: Carbamazepine/therapeutic use
  8. Then SM, Rani ZZ, Raymond AA, Ratnaningrum S, Jamal R
    Asian Pac J Allergy Immunol, 2011 Sep;29(3):290-3.
    PMID: 22053601
    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.
    Matched MeSH terms: Carbamazepine/therapeutic use
  9. Ngeow WC, Nair R
    PMID: 20219585 DOI: 10.1016/j.tripleo.2009.03.021
    This article illustrates a case of persistent trigeminal neuralgia in a medically compromised 65-year-old female who did not respond to pharmacotherapy. She had undergone several peripheral neurectomies as well as a failed right posterior fossa exploration that resulted in a cerebrospinal fluid leak. Persistent pain over the right external nasal area and right mental region was relieved for several hours after daily injections of bupivacaine. A trial of a single dose of 100 units of botulinum toxin type A (BOTOX) diluted in 2.5 mL saline was injected into the external nasal trigger zone (60 units) and to the mental nerve region (40 units). She achieved complete pain relief in the external nasal region for 5 months. Pain recurred and the site was again injected with 100 units of botulinum toxin type A (BOTOX). Pain relief at the mental region was partial. This was finally controlled with peripheral neurectomy. The patient was pain free with a maintenance dose of 200 mg carbamazepine daily for about 1 year, after which she elected to undergo stereotactic gamma knife radiosurgery when pain recurred at the external nasal region.
    Matched MeSH terms: Carbamazepine/therapeutic use
  10. Ab Rahman AF, Ibrahim MI, Ismail HI, Seng TB
    Pharm World Sci, 2005 Oct;27(5):403-6.
    PMID: 16341748
    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.
    Matched MeSH terms: Carbamazepine/therapeutic use
  11. Yeap LL, Lim KS, Ng CC, Hui-Ping Khor A, Lo YL
    Ther Drug Monit, 2014 Feb;36(1):3-9.
    PMID: 24342894 DOI: 10.1097/FTD.0000000000000024
    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.
    Matched MeSH terms: Carbamazepine/therapeutic use
  12. Haerian BS, Lim KS, Mohamed EH, Tan HJ, Tan CT, Raymond AA, et al.
    Seizure, 2011 Jun;20(5):387-94.
    PMID: 21316268 DOI: 10.1016/j.seizure.2011.01.008
    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.
    Matched MeSH terms: Carbamazepine/therapeutic use
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