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Aldhalaan H, AlBakheet A, AlRuways S, AlMutairi N, AlNakiyah M, AlGhofaili R, Cardona-Londoño KJ, Alahmadi KO, AlQudairy H, AlRasheed MM, Colak D, Arold ST, Kaya N. A Novel GEMIN4 Variant in a Consanguineous Family Leads to Neurodevelopmental Impairment with Severe Microcephaly, Spastic Quadriplegia, Epilepsy, and Cataracts. Genes (Basel) 2021; 13:genes13010092. [PMID: 35052432 PMCID: PMC8774908 DOI: 10.3390/genes13010092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/24/2021] [Accepted: 12/25/2021] [Indexed: 12/24/2022] Open
Abstract
Pathogenic variants in GEMIN4 contribute to a hereditary disorder characterized by neurodevelopmental features, microcephaly, cataracts, and renal abnormalities (known as NEDMCR). To date, only two homoallelic variations have been linked to the disease. Moreover, clinical features associated with the variants have not been fully elucidated yet. Here, we identified a novel variant in GEMIN4 (NM_015721:exon2:c.440A>G:p.His147Arg) in two siblings from a consanguineous Saudi family by using whole exome sequencing followed by Sanger sequence verification. We comprehensively investigated the patients’ clinical features, including brain imaging and electroencephalogram findings, and compared their phenotypic characteristics with those of previously reported cases. In silico prediction and structural modeling support that the p.His147Arg variant is pathogenic.
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Affiliation(s)
- Hesham Aldhalaan
- Neurosciences Department, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia;
| | - Albandary AlBakheet
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
| | - Sarah AlRuways
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Nouf AlMutairi
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Maha AlNakiyah
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Reema AlGhofaili
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Kelly J. Cardona-Londoño
- Division of Biological and Environmental Sciences and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (K.J.C.-L.); (S.T.A.)
| | - Khalid Omar Alahmadi
- Department of Radiology, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia;
| | - Hanan AlQudairy
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
| | - Maha M. AlRasheed
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Dilek Colak
- Department of Biostatistics, Epidemiology and Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia;
| | - Stefan T. Arold
- Division of Biological and Environmental Sciences and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (K.J.C.-L.); (S.T.A.)
| | - Namik Kaya
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Correspondence: ; Tel.: +966-11-4647272 (ext. 39612)
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Pal R, Singh K, Khan SA, Chawla P, Kumar B, Akhtar MJ. Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction. Eur J Med Chem 2021; 226:113890. [PMID: 34628237 DOI: 10.1016/j.ejmech.2021.113890] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 09/01/2021] [Accepted: 09/29/2021] [Indexed: 12/22/2022]
Abstract
Several generations of antiepileptic drugs (AEDs) are available in the market for the treatment of seizures, but these are amalgamated with acute to chronic side effects. The most common side effects of AEDs are dose-related, but some are idiosyncratic adverse drug reactions (ADRs) that transpire due to the formation of reactive metabolite (RM) after the bioactivation process. Because of the adverse reactions patients usually discontinue the medication in between the treatment. The AEDs such as valproic acid, lamotrigine, phenytoin etc., can be categorized under such types because they form the RM which may prevail with life-threatening adverse effects or immune-mediated reactions. Hepatotoxicity, teratogenicity, cutaneous hypersensitivity, dizziness, addiction, serum sickness reaction, renal calculi, metabolic acidosis are associated with the metabolites of drugs such as arene oxide, N-desmethyldiazepam, 2-(1-hydroxyethyl)-2-methylsuccinimide, 2-(sulphamoy1acetyl)-phenol, E-2-en-VPA and 4-en-VPA and carbamazepine-10,11-epoxide, etc. The major toxicities are associated with the moieties that are either capable of forming RM or the functional groups may itself be too reactive prior to the metabolism. These functional groups or fragment structures are typically known as structural alerts or toxicophores. Therefore, minimizing the bioactivation potential of lead structures in the early phases of drug discovery by a modification to low-risk drug molecules is a priority for the pharmaceutical companies. Additionally, excellent potency and pharmacokinetic (PK) behaviour help in ensuring that appropriate (low dose) candidate drugs progress into the development phase. The current review discusses about RMs in the anticonvulsant drugs along with their mechanism vis-a-vis research efforts that have been taken to minimize the toxic effects of AEDs therapy.
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Affiliation(s)
- Rohit Pal
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India
| | - Karanvir Singh
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India
| | - Shah Alam Khan
- Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO 620, PC 130, Azaiba, Bousher, Muscat, Oman
| | - Pooja Chawla
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India
| | - Bhupinder Kumar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India.
| | - Md Jawaid Akhtar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India; Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO 620, PC 130, Azaiba, Bousher, Muscat, Oman.
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Impact of Age and Genotype on Serum Concentrations of Valproic Acid and Its Hepatotoxic Metabolites in Chinese Pediatric Patients With Epilepsy. Ther Drug Monit 2020; 42:760-765. [DOI: 10.1097/ftd.0000000000000751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Guo HL, Jing X, Sun JY, Hu YH, Xu ZJ, Ni MM, Chen F, Lu XP, Qiu JC, Wang T. Valproic Acid and the Liver Injury in Patients with Epilepsy: An Update. Curr Pharm Des 2020; 25:343-351. [PMID: 30931853 DOI: 10.2174/1381612825666190329145428] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/25/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Valproic acid (VPA) as a widely used primary medication in the treatment of epilepsy is associated with reversible or irreversible hepatotoxicity. Long-term VPA therapy is also related to increased risk for the development of non-alcoholic fatty liver disease (NAFLD). In this review, metabolic elimination pathways of VPA in the liver and underlying mechanisms of VPA-induced hepatotoxicity are discussed. METHODS We searched in PubMed for manuscripts published in English, combining terms such as "Valproic acid", "hepatotoxicity", "liver injury", and "mechanisms". The data of screened papers were analyzed and summarized. RESULTS The formation of VPA reactive metabolites, inhibition of fatty acid β-oxidation, excessive oxidative stress and genetic variants of some enzymes, such as CPS1, POLG, GSTs, SOD2, UGTs and CYPs genes, have been reported to be associated with VPA hepatotoxicity. Furthermore, carnitine supplementation and antioxidants administration proved to be positive treatment strategies for VPA-induced hepatotoxicity. CONCLUSION Therapeutic drug monitoring (TDM) and routine liver biochemistry monitoring during VPA-therapy, as well as genotype screening for certain patients before VPA administration, could improve the safety profile of this antiepileptic drug.
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Affiliation(s)
- Hong-Li Guo
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Xia Jing
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jie-Yu Sun
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ya-Hui Hu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ze-Jun Xu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ming-Ming Ni
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Feng Chen
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Xiao-Peng Lu
- Department of Neurology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jin-Chun Qiu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Tengfei Wang
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN, United States
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Challenges for Detecting Valproic Acid in a Nontargeted Urine Drug Screening Method. Ther Drug Monit 2017; 39:457-460. [DOI: 10.1097/ftd.0000000000000417] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Silva MFB, Aires CCP, Luis PBM, Ruiter JPN, IJlst L, Duran M, Wanders RJA, Tavares de Almeida I. Valproic acid metabolism and its effects on mitochondrial fatty acid oxidation: a review. J Inherit Metab Dis 2008; 31:205-16. [PMID: 18392741 DOI: 10.1007/s10545-008-0841-x] [Citation(s) in RCA: 253] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/12/2008] [Accepted: 02/15/2008] [Indexed: 12/25/2022]
Abstract
Valproic acid (VPA; 2-n-propylpentanoic acid) is widely used as a major drug in the treatment of epilepsy and in the control of several types of seizures. Being a simple fatty acid, VPA is a substrate for the fatty acid beta-oxidation (FAO) pathway, which takes place primarily in mitochondria. The toxicity of valproate has long been considered to be due primarily to its interference with mitochondrial beta-oxidation. The metabolism of the drug, its effects on enzymes of FAO and their cofactors such as CoA and/or carnitine will be reviewed. The cumulative consequences of VPA therapy in inborn errors of metabolism (IEMs) and the importance of recognizing an underlying IEM in cases of VPA-induced steatosis and acute liver toxicity are two different concepts that will be emphasized.
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Affiliation(s)
- M F B Silva
- Centro de Patogénese Molecular-UBMBE, iMed.UL, Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal.
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Zhou S, Chan E, Duan W, Huang M, Chen YZ. Drug bioactivation, covalent binding to target proteins and toxicity relevance. Drug Metab Rev 2005; 37:41-213. [PMID: 15747500 DOI: 10.1081/dmr-200028812] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A number of therapeutic drugs with different structures and mechanisms of action have been reported to undergo metabolic activation by Phase I or Phase II drug-metabolizing enzymes. The bioactivation gives rise to reactive metabolites/intermediates, which readily confer covalent binding to various target proteins by nucleophilic substitution and/or Schiff's base mechanism. These drugs include analgesics (e.g., acetaminophen), antibacterial agents (e.g., sulfonamides and macrolide antibiotics), anticancer drugs (e.g., irinotecan), antiepileptic drugs (e.g., carbamazepine), anti-HIV agents (e.g., ritonavir), antipsychotics (e.g., clozapine), cardiovascular drugs (e.g., procainamide and hydralazine), immunosupressants (e.g., cyclosporine A), inhalational anesthetics (e.g., halothane), nonsteroidal anti-inflammatory drugs (NSAIDSs) (e.g., diclofenac), and steroids and their receptor modulators (e.g., estrogens and tamoxifen). Some herbal and dietary constituents are also bioactivated to reactive metabolites capable of binding covalently and inactivating cytochrome P450s (CYPs). A number of important target proteins of drugs have been identified by mass spectrometric techniques and proteomic approaches. The covalent binding and formation of drug-protein adducts are generally considered to be related to drug toxicity, and selective protein covalent binding by drug metabolites may lead to selective organ toxicity. However, the mechanisms involved in the protein adduct-induced toxicity are largely undefined, although it has been suggested that drug-protein adducts may cause toxicity either through impairing physiological functions of the modified proteins or through immune-mediated mechanisms. In addition, mechanism-based inhibition of CYPs may result in toxic drug-drug interactions. The clinical consequences of drug bioactivation and covalent binding to proteins are unpredictable, depending on many factors that are associated with the administered drugs and patients. Further studies using proteomic and genomic approaches with high throughput capacity are needed to identify the protein targets of reactive drug metabolites, and to elucidate the structure-activity relationships of drug's covalent binding to proteins and their clinical outcomes.
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Affiliation(s)
- Shufeng Zhou
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
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Silva MFB, Ruiter JPN, Overmars H, Bootsma AH, van Gennip AH, Jakobs C, Duran M, Tavares de Almeida I, Wanders RJA. Complete beta-oxidation of valproate: cleavage of 3-oxovalproyl-CoA by a mitochondrial 3-oxoacyl-CoA thiolase. Biochem J 2002; 362:755-60. [PMID: 11879205 PMCID: PMC1222442 DOI: 10.1042/0264-6021:3620755] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The beta-oxidation of valproic acid (VPA; 2-n-propylpentanoic acid) was investigated in vitro in intact rat liver mitochondria incubated with (3)H-labelled VPA. The metabolism of [4,5-(3)H(2)]VPA and [2-(3)H]VPA was studied by analysing the different acyl-CoA intermediates formed by reverse-phase HPLC with radiochemical detection. Valproyl-CoA, Delta(2(E))-valproyl-CoA,3-hydroxyvalproyl-CoA and 3-oxovalproyl-CoA (labelled and non-labelled) were determined using continuous on-line radiochemical and UV detection. The formation of these intermediates was investigated using the two tritiated precursors in respiratory states 3 and 4. Valproyl-CoA was present at highest concentrations under both conditions. Two distinct labelled peaks were found, which were identified as (3)H(2)O and [4,5-(3)H(2)]3-oxo-VPA. The formation of (3)H(2)O strongly suggested that VPA underwent complete beta-oxidation and that [4,5-(3)H(2)]3-oxo-VPA was formed by hydrolysis of the corresponding thioester. The hypothesis that 3-oxovalproyl-CoA undergoes thiolytic cleavage was investigated further. For this purpose a mito chondrial lysate was incubated with synthetic 3-oxovalproyl-CoA, carnitine and carnitine acetyltransferase for subsequent monitoring of the formation of propionylcarnitine and pentanoylcarnitine using electrospray ionization tandem MS. The detection of these compounds demonstrated unequivocally that the intermediate 3-oxovalproyl-CoA is a substrate of a mitochondrial thiolase, producing propionyl-CoA and pentanoyl-CoA, thus demonstrating the complete beta-oxidation of VPA in the mitochondrion. Our data should lead to a re-evaluation of the generally accepted concept that the biotransformation of VPA by mitochondrial beta-oxidation is incomplete.
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Affiliation(s)
- Margarida F B Silva
- Department of Clinical Chemistry and Paediatrics, University of Amsterdam, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Abstract
The authors investigated whether methsuximide affects serum levels of valproic acid. Pre-morning-dose serum valproic acid levels were measured in 17 patients (12 male, 5 female; age range, 8-19; mean, 14.5 years) who either started or stopped taking methsuximide but whose dose of valproate and other medication remained unchanged. Four of these patients both started and stopped taking methsuximide. For the whole group the mean valproic acid level (+/- standard error) while not taking methsuximide was 81.9 +/- 5.3 mg/L and while taking methsuximide was 55.7 +/- 4.3 mg/L. The difference between the means was highly significant (paired t test, p < 0.001). The mean valproic acid serum level before taking methsuximide was 85.4 +/- 4.5 mg/L (14 patients), which decreased to 58.2 +/- 4.8 mg/L while taking methsuximide (difference highly significant, p < 0.001). In the eight patients who stopped taking methsuximide the mean serum level increased from 49.8 +/- 7.5 mg/L to 71.7 +/- 8.5 mg/L (difference significant p = 0.025). Because methsuximide reduces valproic acid serum levels, it may be necessary to increase the valproate dose when methsuximide is added or reduce the valproate dose when methsuximide therapy stops, to avoid loss of seizure control or valproate toxicity respectively.
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Affiliation(s)
- F M Besag
- St Piers Lingfield, (Now The National Centre for Young People With Epilepsy) Surrey, England, UK.
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McLaughlin DB, Eadie MJ, Parker-Scott SL, Addison RS, Henderson RD, Hooper WD, Dickinson RG. Valproate metabolism during valproate-associated hepatotoxicity in a surviving adult patient. Epilepsy Res 2000; 41:259-68. [PMID: 10962217 DOI: 10.1016/s0920-1211(00)00151-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The plasma profiles of valproate (VPA), its beta-oxidation metabolites E-2-en-VPA and 3-oxo-VPA and its terminal desaturation metabolite 4-en-VPA, have been measured in a patient receiving NaVPA 1000 mg twice per day from early in the course of serious hepatotoxicity and for 2 weeks after the drug was stopped. Concurrent profiles of liver, renal and haematological function parameters were available. Relative to concurrent plasma VPA concentrations, E-2-en-VPA concentrations were not different to those of the VPA-treated epileptic population at any stage of the illness, whereas 3-oxo-VPA concentrations relative to concurrent VPA concentrations were abnormally high early in the toxicity, abnormally low at its peak (3-5 days later), and comfortably within normal limits for the treated epileptic population late in the recovery phase (9-13 days from the onset). When measurable, plasma 4-en-VPA concentrations were not elevated. The elimination half-life of VPA during the recovery phase was 100 h, which is some 6-12 times greater than values reported for this parameter in normal patients. These data clearly define, in this patient, a link between idiosyncratic VPA-associated hepatotoxicity at its onset and peak and the later stages of VPA beta-oxidation. Whether the beta-oxidation abnormalities are causative or a consequence of an as yet undefined defect is unknown. In this patient, 4-en-VPA was unlikely to have been involved in the pathogenesis of the toxicity.
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Affiliation(s)
- D B McLaughlin
- Department of Medicine, Clinical Sciences Building, University of Queensland, Royal Brisbane Hospital, QLD 4029, Brisbane, Australia
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Azaroual N, Imbenotte M, Cartigny B, Leclerc F, Vallée L, Lhermitte M, Vermeersch G. Valproic acid intoxication identified by1H and1H-13C correlated NMR spectroscopy of urine samples. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2000. [DOI: 10.1007/bf02590644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Addison RS, Parker-Scott SL, Hooper WD, Eadie MJ, Dickinson RG. Effect of naproxen co-administration on valproate disposition. Biopharm Drug Dispos 2000; 21:235-42. [PMID: 11304722 DOI: 10.1002/bdd.235] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The effects of co-administration of the antiepileptic agent valproic acid (VPA) and the non-steroidal anti-inflammatory drug naproxen (NAP) on their relative dispositions (particularly with respect to glucuronidation) were investigated in human volunteers. Seven healthy males received each drug alone and then in combination (orally twice daily for seven days, 500 mg sodium VPA, 500 mg NAP). On day 7 of each dosing phase, serial plasma and 24 h urine samples were collected for analysis. Co-administration of NAP resulted in significant increases (about 20%, p<0.05) in the apparent plasma clearance of total VPA and in the unbound fraction of VPA in plasma, with the apparent plasma clearance of unbound VPA being unchanged. There were associated increases in the formation clearances to urinary VPA-glucuronide and 3-oxo-VPA, though these were relatively greater for the glucuronidation pathway (and remained significant when formation clearances were calculated using the unbound fraction of drug in plasma). The data thus point to a shift towards glucuronidation as a result of the NAP-induced increase in the unbound fraction of VPA in plasma. By contrast, VPA co-administration caused a decrease (of about 10%, p<0.05) in the apparent plasma clearance of total NAP. Taken in hand with in vitro results showing a VPA-induced displacement (of about 40%) of NAP from plasma protein binding sites, the data strongly support a role for diminished glucuronidation of NAP and its desmethyl metabolite in the presence of co-administered VPA.
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Affiliation(s)
- R S Addison
- Centre for Studies in Drug Disposition, The University of Queensland, Clinical Sciences Building, Royal Brisbane Hospital, Queensland, Australia.
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Azaroual N, Imbenotte M, Cartigny B, Leclerc F, Vallée L, Lhermitte M, Vermeersch G. Valproic acid intoxication identified by 1H and 1H-(13)C correlated NMR spectroscopy of urine samples. MAGMA (NEW YORK, N.Y.) 2000; 10:177-82. [PMID: 10873209 DOI: 10.1016/s1352-8661(00)00086-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Analysis of biological fluids by proton and carbon nuclear magnetic resonance spectroscopy (1H and 13C NMR) is a promising tool in clinical biology. We used this method for rapid toxicological screening in the case of two suicide attempts. For each case, a urine sample was analysed at 300 MHz by 1D and 2D sequences (TOCSY and HMBC) in a short experimental time. Quantification was performed by peak integration on the 1D 1H NMR spectrum. For the two patients, results showed the same resonances of the major metabolite, valproyl-O-glucuronide at concentrations of 121 and 44 mmol/l.
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Affiliation(s)
- N Azaroual
- Laboratoire de Physique, UPRESA CNRS 8009, Laboratoire d'Application RMN de l'Universit¿ de Lille 2, BP 83, 59006 Cedex, Lille, France
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McLaughlin DB, Andrews JA, Hooper WD, Cannell GR, Eadie MJ, Dickinson RG. Apparent autoinduction of valproate beta-oxidation in humans. Br J Clin Pharmacol 2000; 49:409-15. [PMID: 10792197 PMCID: PMC2014955 DOI: 10.1046/j.1365-2125.2000.00191.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS The study aimed to show whether autoinduction of valproate (VPA) along its beta-oxidation pathway occurred upon chronic dosing in humans. METHODS Twelve young volunteers without active illness took sodium valproate (NaVPA) 200 mg orally 12 hourly for 3 weeks. On days 7 and 21, serial blood samples and all urine passed over an interdosing interval from 08.00 to 20.00 h were collected for analysis of VPA and certain metabolites. RESULTS Plasma AUC(0,12 h) of VPA was significantly lower on day 21 than on day 7 (2.40 vs 2.84 micromol ml-1 h, 95% CI for the difference 0.13-0.81 micromol ml-1 h). Significant differences in plasma AUC(0,12 h) of the beta-oxidation metabolites E-2-en-VPA and 3-oxo-VPA were not found. However, formation clearances of plasma VPA to urinary E-2-en-VPA and 3-oxo-VPA were significantly increased from day 7 to day 21 (0. 010 vs 0.024 and 2.57 vs 3.60 ml kg-1 h-1, respectively, 95% CI for the differences -0.025 to -0.004 and -1.72 to -0.34 ml kg-1 h-1, respectively). Formation clearances to VPA-glucuronide (0.534 vs 0. 505 ml kg-1 h-1) and 4-OH-VPA (0.112 vs 0.110 ml kg-1 h-1) were not significantly different. CONCLUSIONS Regular low dose VPA intake in humans over a period of 3 weeks appears to be associated with a small induction of its metabolism by the beta-oxidation pathway, but not by glucuronidation or 4-hydroxylation.
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Affiliation(s)
- D B McLaughlin
- Centre for Studies in Drug Disposition, Department of Medicine, University of Queensland at Royal Brisbane Hospital, Clinical Sciences Building, Royal Brisbane Hospital, QLD 4029, Australia
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