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Biochimica Et Biophysica Acta Oct 2016GFAP is the major intermediate filament protein in mature astrocytes. Its increased expression and aggregation was firstly associated to Alexander's disease, and...
BACKGROUND
GFAP is the major intermediate filament protein in mature astrocytes. Its increased expression and aggregation was firstly associated to Alexander's disease, and successively in different neurological diseases including scrapie, Alzheimer's and Creutzfeld-Jacob diseases. Recently, ceftriaxone a multi-potent β-lactam antibiotic able to overcome the blood-brain barrier, successfully eliminated the cellular toxic effects of misfolded mutated GFAP, similarly to phenytoin sodium, in a cellular model of Alexander's disease and inhibited α-synuclein aggregation protecting PC12 cells from the exposure to 6-hydroxydopamine.
METHODS
In this study, synchrotron radiation circular dichroism spectroscopy has been used to obtain structural information about the GFAP-ceftriaxone (phenytoin) interactions, while computational methods allowed the identification of the relevant putative binding site of either ceftriaxone or phenytoin on the dimer structure of GFAP, permitting to rationalize the spectroscopic experimental results.
RESULTS
We found that GFAP exhibited enhanced stability upon the addition of two equivalents of each ligands with ceftriaxone imparting a more spontaneous interactions and a more ordered complex system than phenytoin.
CONCLUSIONS
SRCD data and MD models indicate a stronger protective effect of ceftriaxone in neurological disorders characterized by an increased production and polymerization of GFAP.
GENERAL SIGNIFICANCE
This result, in addition to our previous works in which we documented that ceftriaxone interacts with α-synuclein inhibiting its pathological aggregation and that a cyclical treatment with this molecule in a patient with adult-onset Alexander's disease halted, and partly reversed, the progression of neurodegeneration, suggests the possibility of a chaperone-like effect of ceftriaxone on protein involved in specific neurodegenerative diseases.
Topics: Alexander Disease; Animals; Astrocytes; Binding Sites; Ceftriaxone; Glial Fibrillary Acidic Protein; Humans; Intermediate Filament Proteins; Molecular Docking Simulation; Molecular Dynamics Simulation; Nerve Degeneration; PC12 Cells; Phenytoin; Protein Aggregation, Pathological; Rats; alpha-Synuclein
PubMed: 27133445
DOI: 10.1016/j.bbagen.2016.04.021 -
Pharmaceuticals (Basel, Switzerland) May 2018Neuropathic pain can be disabling, and is often difficult to treat. Within a year, over half of all patients stop taking their prescribed neuropathic pain medication,...
BACKGROUND
Neuropathic pain can be disabling, and is often difficult to treat. Within a year, over half of all patients stop taking their prescribed neuropathic pain medication, which is most probably due to side effects or disappointing analgesic results. Therefore, new therapies are needed to alleviate neuropathic pain. As such, topical analgesics could be a new inroad in the treatment of neuropathic pain. In 2014, we developed a new topical formulation containing either phenytoin or sodium phenytoin. After optimization of the formulation, we were able to reach a 10% concentration and combine phenytoin with other co-analgesics in the same base cream.
OBJECTIVE
To describe a series of 70 neuropathic pain patients who were treated with phenytoin cream.
MATERIAL AND METHODS
Cases treated with phenytoin 5% or 10% creams were gathered. The mean onset of pain relief, the duration of effect, and reduction in pain intensity measured on the 11-point numerical rating scale (NRS) were all studied. A single-blind response test with phenytoin 10% and placebo creams was conducted on 12 patients in order to select responders prior to prescribing the active cream. Plasma phenytoin concentrations were measured in 16 patients.
RESULTS
Nine patients applied phenytoin 5% cream, and 61 patients used phenytoin 10% cream. After grouping the effects of all of the patients, the mean onset of pain relief was 16.3 min (SD: 14.8), the mean duration of analgesia was 8.1 h (SD: 9.1), and the mean pain reduction on the NRS was 61.2% (SD: 25.0). The mean pain reduction on the NRS while using phenytoin cream was statistically significant compared with the baseline, with a reduction of 4.5 (CI: 4.0 to 5.0, < 0.01). The 12 patients on whom a single-blind response test was performed experienced a statistically significant reduction in pain in the area where the phenytoin 10% cream was applied in comparison to the area where the placebo cream was applied ( < 0.01). Thirty minutes after the test application, the mean pain reduction on the NRS in the areas where the phenytoin 10% cream and the placebo cream were applied was 3.3 (CI: 2.3 to 4.4, < 0.01) and 1.1 (CI: 0.4 to 1.9, < 0.05), respectively. In all 16 patients, the phenytoin plasma levels were below the limit of detection. So far, no systemic side effects were reported. Two patients only reported local side effects: a transient burning aggravation and skin rash.
CONCLUSION
In this case series, the phenytoin cream had reduced neuropathic pain considerably, with a fast onset of analgesic effect.
PubMed: 29843362
DOI: 10.3390/ph11020053 -
Human Genomics Feb 2023Genetic variability in the cytochrome P450 CYP2C9 constitutes an important predictor for efficacy and safety of various commonly prescribed drugs, including coumarin...
BACKGROUND
Genetic variability in the cytochrome P450 CYP2C9 constitutes an important predictor for efficacy and safety of various commonly prescribed drugs, including coumarin anticoagulants, phenytoin and multiple non-steroidal anti-inflammatory drugs (NSAIDs). A global map of CYP2C9 variability and its inferred functional consequences has been lacking.
RESULTS
Frequencies of eight functionally relevant CYP2C9 alleles (*2, *3, *5, *6, *8, *11, *13 and *14) were analyzed. In total, 108 original articles were identified that included genotype data from a total of 81,662 unrelated individuals across 70 countries and 40 unique ethnic groups. The results revealed that CYP2C9*2 was most abundant in Europe and the Middle East, whereas CYP2C9*3 was the main reason for reduced CYP2C9 activity across South Asia. Our data show extensive variation within superpopulations with up to tenfold differences between geographically adjacent populations in Malaysia, Thailand and Vietnam. Translation of genetic CYP2C9 variability into functional consequences indicates that up to 40% of patients in Southern Europe and the Middle East might benefit from warfarin and phenytoin dose reductions, while 3% of patients in Southern Europe and Israel are recommended to reduce starting doses of NSAIDs.
CONCLUSIONS
This study provides a comprehensive map of the genetic and functional variability of CYP2C9 with high ethnogeographic resolution. The presented data can serve as a useful resource for CYP2C9 allele and phenotype frequencies and might guide the optimization of genotyping strategies, particularly for indigenous and founder populations with distinct genetic profiles.
Topics: Alleles; Anti-Inflammatory Agents, Non-Steroidal; Asia, Southern; Cytochrome P-450 CYP2C9; Phenytoin; Humans; Anticoagulants; Genetics, Population
PubMed: 36855170
DOI: 10.1186/s40246-023-00461-z -
Molecular Cancer Jan 2015Voltage-gated Na(+) channels (VGSCs) are heteromeric protein complexes containing pore-forming α subunits and smaller, non-pore-forming β subunits. VGSCs are...
BACKGROUND
Voltage-gated Na(+) channels (VGSCs) are heteromeric protein complexes containing pore-forming α subunits and smaller, non-pore-forming β subunits. VGSCs are classically expressed in electrically excitable cells, e.g. neurons. VGSCs are also expressed in tumour cells, including breast cancer (BCa) cells, where they enhance cellular migration and invasion. However, despite extensive work defining in detail the molecular mechanisms underlying the expression of VGSCs and their pro-invasive role in cancer cells, there has been a notable lack of clinically relevant in vivo data exploring their value as potential therapeutic targets.
FINDINGS
We have previously reported that the VGSC-blocking antiepileptic drug phenytoin inhibits the migration and invasion of metastatic MDA-MB-231 cells in vitro. The purpose of the present study was to establish whether VGSCs might be viable therapeutic targets by testing the effect of phenytoin on tumour growth and metastasis in vivo. We found that expression of Nav1.5, previously detected in MDA-MB-231 cells in vitro, was retained on cells in orthotopic xenografts. Treatment with phenytoin, at a dose equivalent to that used to treat epilepsy (60 mg/kg; daily), significantly reduced tumour growth, without affecting animal weight. Phenytoin also reduced cancer cell proliferation in vivo and invasion into surrounding mammary tissue. Finally, phenytoin significantly reduced metastasis to the liver, lungs and spleen.
CONCLUSIONS
This is the first study showing that phenytoin reduces breast tumour growth and metastasis in vivo. We propose that pharmacologically targeting VGSCs, by repurposing antiepileptic or antiarrhythmic drugs, should be further studied as a potentially novel anti-cancer therapy.
Topics: Animals; Anticonvulsants; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Female; Humans; Mice; Neoplasm Metastasis; Neovascularization, Pathologic; Phenytoin; Sodium Channel Blockers; Sodium Channels; Tumor Burden; Xenograft Model Antitumor Assays
PubMed: 25623198
DOI: 10.1186/s12943-014-0277-x -
Cancers Sep 2022Cancer is a major health burden worldwide. Although the plethora of molecular targets identified in the last decades and the deriving developed treatments, which... (Review)
Review
Cancer is a major health burden worldwide. Although the plethora of molecular targets identified in the last decades and the deriving developed treatments, which significantly improved patients' outcome, the occurrence of resistance to therapies remains the major cause of relapse and mortality. Thus, efforts in identifying new markers to be exploited as molecular targets in cancer therapy are needed. This review will first give a glance on the diagnostic and therapeutic significance of histone deacetylase (HDAC) and voltage gated ion channels (VGICs) in cancer. Nevertheless, HDAC and VGICs have also been reported as molecular targets through which antiepileptic drugs (AEDs) seem to exert their anticancer activity. This should be claimed as a great advantage. Indeed, due to the slowness of drug approval procedures, the attempt to turn to off-label use of already approved medicines would be highly preferable. Therefore, an updated and accurate overview of both preclinical and clinical data of commonly prescribed AEDs (mainly valproic acid, lamotrigine, carbamazepine, phenytoin and gabapentin) in breast, prostate, brain and other cancers will follow. Finally, a glance at the emerging attempt to administer AEDs by means of opportunely designed drug delivery systems (DDSs), so to limit toxicity and improve bioavailability, is also given.
PubMed: 36139561
DOI: 10.3390/cancers14184401 -
British Journal of Clinical Pharmacology Jul 2016The aim of this study was to perform an up-to-date systematic review and meta-analysis on the efficacy and safety of prophylactic administration of levetiracetam in... (Comparative Study)
Comparative Study Meta-Analysis Review
AIMS
The aim of this study was to perform an up-to-date systematic review and meta-analysis on the efficacy and safety of prophylactic administration of levetiracetam in brain tumour patients.
METHOD
A systematic review of studies published until April 2015 was conducted using Scopus/Elsevier, EMBASE and MEDLINE. The search was limited to articles reporting results from adult patients, suffering from brain tumour, undergoing supratentorial craniotomy for tumour resection or biopsy and administered levetiracetam in the perioperative period for seizure prophylaxis. Outcomes included the efficacy and safety of levetiracetam, as well as the tolerability of the specific regimen, defined by the discontinuation of the treatment due to side effects.
RESULTS
The systematic review included 1148 patients from 12 studies comparing levetiracetam with no treatment, phenytoin and valproate, while only 243 patients from three studies, comparing levetiracetam vs phenytoin efficacy and safety, were included in the meta-analysis. The combined results from the meta-analysis showed that levetiracetam administration was followed by significantly fewer seizures than treatment with phenytoin (OR = 0.12 [0.03-0.42]: χ(2) = 1.76: I(2) = 0%). Analysis also showed significantly fewer side effects in patients receiving levetiracetam, compared to other groups (P < 0.05). The combined results showed fewer side effects in the levetiracetam group compared to the phenytoin group (OR = 0.65 [0.14-2.99]: χ(2) = 8.79: I(2) = 77%).
CONCLUSIONS
The efficacy of prophylaxis with levetiracetam seems to be superior to that with phenytoin and valproate administration. Moreover, levetiracetam use demonstrates fewer side effects in brain tumour patients. Nevertheless, high risk of bias and moderate methodological quality must be taken into account when considering these results.
Topics: Anticonvulsants; Craniotomy; Humans; Levetiracetam; Perioperative Care; Phenytoin; Piracetam; Seizures; Supratentorial Neoplasms; Valproic Acid
PubMed: 26945547
DOI: 10.1111/bcp.12926 -
American Journal of Kidney Diseases :... Feb 2016The Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup conducted a systematic literature review using a standardized process to develop evidence-based... (Review)
Review
The Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup conducted a systematic literature review using a standardized process to develop evidence-based recommendations on the use of extracorporeal treatment (ECTR) in patients with phenytoin poisoning. The authors reviewed all articles, extracted data, summarized findings, and proposed structured voting statements following a predetermined format. A 2-round modified Delphi method was used to reach a consensus on voting statements, and the RAND/UCLA Appropriateness Method was used to quantify disagreement. 51 articles met the inclusion criteria. Only case reports, case series, and pharmacokinetic studies were identified, yielding a very low quality of evidence. Clinical data from 31 patients and toxicokinetic grading from 46 patients were abstracted. The workgroup concluded that phenytoin is moderately dialyzable (level of evidence = C) despite its high protein binding and made the following recommendations. ECTR would be reasonable in select cases of severe phenytoin poisoning (neutral recommendation, 3D). ECTR is suggested if prolonged coma is present or expected (graded 2D) and it would be reasonable if prolonged incapacitating ataxia is present or expected (graded 3D). If ECTR is used, it should be discontinued when clinical improvement is apparent (graded 1D). The preferred ECTR modality in phenytoin poisoning is intermittent hemodialysis (graded 1D), but hemoperfusion is an acceptable alternative if hemodialysis is not available (graded 1D). In summary, phenytoin appears to be amenable to extracorporeal removal. However, because of the low incidence of irreversible tissue injury or death related to phenytoin poisoning and the relatively limited effect of ECTR on phenytoin removal, the workgroup proposed the use of ECTR only in very select patients with severe phenytoin poisoning.
Topics: Coma; Education; Humans; Phenytoin; Practice Guidelines as Topic; Renal Dialysis; Treatment Outcome
PubMed: 26578149
DOI: 10.1053/j.ajkd.2015.08.031 -
The Cochrane Database of Systematic... Apr 2020This is an updated version of the Cochrane Review previously published in 2018. The incidence of seizures following supratentorial craniotomy for non-traumatic pathology...
BACKGROUND
This is an updated version of the Cochrane Review previously published in 2018. The incidence of seizures following supratentorial craniotomy for non-traumatic pathology has been estimated to be between 15% to 20%; however, the risk of experiencing a seizure appears to vary from 3% to 92% over a five-year period. Postoperative seizures can precipitate the development of epilepsy; seizures are most likely to occur within the first month of cranial surgery. The use of antiepileptic drugs (AEDs) administered pre- or postoperatively to prevent seizures following cranial surgery has been investigated in a number of randomised controlled trials (RCTs).
OBJECTIVES
To determine the efficacy and safety of AEDs when used prophylactically in people undergoing craniotomy and to examine which AEDs are most effective.
SEARCH METHODS
For the latest update we searched the following databases on 29 September 2019: Cochrane Epilepsy Group Specialized Register, CENTRAL, MEDLINE, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP). We did not apply any language restrictions.
SELECTION CRITERIA
We included RCTs of people with no history of epilepsy who were undergoing craniotomy for either therapeutic or diagnostic reasons. We included trials with adequate randomisation methods and concealment; these could either be blinded or unblinded parallel trials. We did not stipulate a minimum treatment period, and we included trials using active drugs or placebo as a control group.
DATA COLLECTION AND ANALYSIS
Three review authors (JW, JG, YD) independently selected trials for inclusion, extracted data and assessed risk of bias. We resolved any disagreements through discussion. Outcomes investigated included the number of participants experiencing seizures (early (occurring within first week following craniotomy), and late (occurring after first week following craniotomy)), the number of deaths and the number of people experiencing disability and adverse effects. Due to the heterogeneous nature of the trials, we did not combine data from the included trials in a meta-analysis; we presented the findings of the review in narrative format. Visual comparisons of outcomes are presented in forest plots.
MAIN RESULTS
We included 10 RCTs (N = 1815), which were published between 1983 and 2015. Three trials compared a single AED (phenytoin) with placebo or no treatment. One, three-armed trial compared two AEDs (phenytoin, carbamazepine) with no treatment. A second three-armed trial compared phenytoin, phenobarbital with no treatment. Of these five trials comparing AEDs with placebo or no treatment, two trials reported a statistically significant advantage for AED treatment compared to controls for early seizure occurrence; all other comparisons showed no clear or statistically significant differences between AEDs and control treatment. None of the trials that were head-to-head comparisons of AEDs (phenytoin versus sodium valproate, phenytoin versus phenobarbital, levetiracetam versus phenytoin, zonisamide versus phenobarbital) reported any statistically significant differences between treatments for either early or late seizure occurrence. Only five trials reported incidences of death. One trial reported statistically significantly fewer deaths in the carbamazepine and no-treatment groups compared with the phenytoin group after 24 months of treatment, but not after six months of treatment. Incidences of adverse effects of treatment were poorly reported; however, three trials did show that significantly more adverse events occurred on phenytoin compared to valproate, placebo, or no treatment. No trials reported any results relating to functional outcomes such as disability. We considered the evidence to be of low certainty for all reported outcomes due to methodological issues and variability of comparisons made in the trials.
AUTHORS' CONCLUSIONS
There is limited, low-certainly evidence to suggest that AED treatment administered prophylactically is either effective or not effective in the prevention of postcraniotomy (early or late) seizures. The current evidence base is limited due to the different methodologies employed in the trials and inconsistencies in the reporting of outcomes including deaths and adverse events. Further evidence from good-quality, contemporary trials is required in order to assess the clinical effectiveness of prophylactic AED treatment compared to placebo or no treatment, or other AEDs in preventing postcraniotomy seizures in this select group of patients.
Topics: Anticonvulsants; Carbamazepine; Craniotomy; Humans; Isoxazoles; Levetiracetam; Phenobarbital; Phenytoin; Piracetam; Postoperative Complications; Randomized Controlled Trials as Topic; Seizures; Valproic Acid; Zonisamide
PubMed: 32343399
DOI: 10.1002/14651858.CD007286.pub5 -
British Journal of Clinical Pharmacology Jun 2021Carbamazepine can cause hypersensitivity reactions in ~10% of patients. An immunogenic effect can be produced by the electrophilic 10,11-epoxide metabolite but not by...
AIMS
Carbamazepine can cause hypersensitivity reactions in ~10% of patients. An immunogenic effect can be produced by the electrophilic 10,11-epoxide metabolite but not by carbamazepine. Hypothetically, certain single nucleotide polymorphisms might increase the formation of immunogenic metabolites, leading ultimately to hypersensitivity reactions. This study explores the role of clinical and genetic factors in the pharmacokinetics (PK) of carbamazepine and 3 metabolites known to be chemically reactive or formed through reactive intermediates.
METHODS
A combination of rich and sparse PK samples were collected from healthy volunteers and epilepsy patients. All subjects were genotyped for 20 single nucleotide polymorphisms in 11 genes known to be involved in the metabolism or transport of carbamazepine and carbamazepine 10,11-epoxide. Nonlinear mixed effects modelling was used to build a population-PK model.
RESULTS
In total, 248 observations were collected from 80 subjects. A 1-compartment PK model with first-order absorption and elimination best described the parent carbamazepine data, with a total clearance of 1.96 L/h, central distribution volume of 164 L and absorption rate constant of 0.45 h . Total daily dose and coadministration of phenytoin were significant covariates for total clearance of carbamazepine. EPHX1-416G/G genotype was a significant covariate for the clearance of carbamazepine 10,11-epoxide.
CONCLUSION
Our data indicate that carbamazepine clearance was affected by total dose and phenytoin coadministration, but not by genetic factors, while carbamazepine 10,11-epoxide clearance was affected by a variant in the microsomal epoxide hydrolase gene. A much larger sample size would be required to fully evaluate the role of genetic variation in carbamazepine pharmacokinetics, and thereby predisposition to carbamazepine hypersensitivity.
Topics: Anticonvulsants; Carbamazepine; Epilepsy; Epoxide Hydrolases; Humans; Phenytoin
PubMed: 33217013
DOI: 10.1111/bcp.14667 -
Epilepsia Open Sep 2017encodes Nav1.6, one of the main voltage-gated sodium channel subunits in the brain, and mutations lead to epileptic encephalopathy. Particular mutations render the...
encodes Nav1.6, one of the main voltage-gated sodium channel subunits in the brain, and mutations lead to epileptic encephalopathy. Particular mutations render the mutant channel more susceptible to inhibition by phenytoin. Yet, the potentially severe side effects of phenytoin maintenance therapy, especially cognitive impairment, are undesirable in these already cognitively impaired patients. We describe a 5-year-old patient with encephalopathy in whom phenytoin proved successful as emergency treatment to prevent clustering of seizures and status epilepticus, thus hospital stays. The ketogenic diet, levetiracetam, zonisamide, topiramate, and phenytoin maintenance therapy resulted in adverse reactions not previously documented in encephalopathy.
PubMed: 29588963
DOI: 10.1002/epi4.12059