Phenytoin poisoning

The Phenytoin Ataxia Enigma Unveiled ''A Case Report''

Background: Phenytoin (PHT) has been approved for the treatment of epilepsy. It belongs to the category of medications with a limited therapeutic window and requires therapeutic drug monitoring (TDM). PTH has been observed to induce a variety of Adverse drug reactions (ADRs) including ataxia, dystonia, nystagmus, dyskinesia, etc. Phenytoin-induced ataxia is an uncommonly observed ADR of Phenytoin whose reports are extremely limited. Case: Herein, we present a case report of a 16-year-old Asian patient with a past history of epilepsy that was admitted to a tertiary care hospital due to the development of ataxia, giddiness, and vomiting when taking Phenytoin in addition to Oxcarbazepine, Clobazam, and Levetiracetam to treat seizures. On admission, Magnetic resonance imaging (MRI) findings revealed bilateral variable cerebrospinal fluid (CSF) lesions in the parieto-occipital region of the periventricular area (periventricular leukomalacia). Additionally, serum Phenytoin levels were observed to be in the toxic range (40 μg/mL) due to which physicians confirmed the ADR to be due to Phenytoin toxicity. Thus, the Phenytoin drug was discontinued in the patient gradually and he was continued on clobazam, oxcarbazepine, and brivaracetam which led to reversal of the ADR in the patient. Conclusion: In this case, ataxia resulted from Phenytoin overdose, as confirmed by MRI and serum tests suggesting that TDM of Phenytoin is essential to prevent ADRs. Given the scarcity of ataxia cases caused by Phenytoin, awareness is lacking within the scientific community. Our aim is to provide insights to promote better monitoring and patient-centered treatment outcomes for epileptic patients.

The Australian Traumatic Brain Injury Initiative: Systematic Review of the Effect of Acute Interventions on Outcome for People With Moderate-Severe Traumatic Brain Injury

The Australian Traumatic Brain Injury Initiative (AUS-TBI) is developing a data resource to enable improved outcome prediction for people with moderate-severe TBI (msTBI) across Australia. Fundamental to this resource is the collaboratively designed data dictionary. This systematic review and consultation aimed to identify acute interventions with potential to modify clinical outcomes for people after msTBI, for inclusion in a data dictionary. Standardized searches were implemented across bibliographic databases from inception through April 2022. English-language reports of randomized controlled trials (RCTs) evaluating any association between any acute intervention and clinical outcome in at least 100 patients with msTBI, were included. A predefined algorithm was used to assign a value to each observed association. Consultation with AUS-TBI clinicians and researchers formed the consensus process for interventions to be included in a single data dictionary. Searches retrieved 14,455 records, of which 124 full-length RCTs were screened, with 35 studies included. These studies evaluated 26 unique acute interventions across 21 unique clinical outcomes. Only 4 interventions were considered to have medium modifying value for any outcome from the review, with an additional 8 interventions agreed upon through the consensus process. The interventions with medium value were tranexamic acid and phenytoin, which had a positive effect on an outcome; and decompressive craniectomy surgery and hypothermia, which negatively affected outcomes. From the systematic review and consensus process, 12 interventions were identified as potential modifiers to be included in the AUS-TBI national data resource.

ROS/Electro Dual-Reactive Nanogel for Targeting Epileptic Foci to Remodel Aberrant Circuits and Inflammatory Microenvironment

Medicinal treatment against epilepsy is faced with intractable problems, especially epileptogenesis that cannot be blocked by clinical antiepileptic drugs (AEDs) during the latency of epilepsy. Abnormal circuits of neurons interact with the inflammatory microenvironment of glial cells in epileptic foci, resulting in recurrent seizures and refractory epilepsy. Herein, we have selected phenytoin (PHT) as a model drug to derive a ROS-responsive and consuming prodrug, which is combined with an electro-responsive group (sulfonate sodium, SS) and an epileptic focus-recognizing group (α-methyl-l-tryptophan, AMT) to form hydrogel nanoparticles (i.e., a nanogel). The nanogel will target epileptic foci, release PHT in response to a high concentration of reactive oxygen species (ROS) in the microenvironment, and inhibit overexcited circuits. Meanwhile, with the clearance of ROS, the nanogel can also reduce oxidative stress and alleviate microenvironment inflammation. Thus, a synergistic regulation of epileptic lesions will be achieved. Our nanogel is expected to provide a more comprehensive strategy for antiepileptic treatment.

Transcranial focused ultrasound-mediated unbinding of phenytoin from plasma proteins for suppression of chronic temporal lobe epilepsy in a rodent model

The efficacy of many anti-epileptic drugs, including phenytoin (PHT), is reduced by plasma protein binding (PPB) that sequesters therapeutically active drug molecules within the bloodstream. An increase in systemic dose elevates the risk of drug side effects, which demands an alternative technique to increase the unbound concentration of PHT in a region-specific manner. We present a low-intensity focused ultrasound (FUS) technique that locally enhances the efficacy of PHT by transiently disrupting its binding to albumin. We first identified the acoustic parameters that yielded the highest PHT unbinding from albumin among evaluated parameter sets using equilibrium dialysis. Then, rats with chronic mesial temporal lobe epilepsy (mTLE) received four sessions of PHT injection, each followed by 30 min of FUS delivered to the ictal region, across 2 weeks. Two additional groups of mTLE rats underwent the same procedure, but without receiving PHT or FUS. Assessment of electrographic seizure activities revealed that FUS accompanying administration of PHT effectively reduced the number and mean duration of ictal events compared to other conditions, without damaging brain tissue or the blood-brain barrier. Our results demonstrated that the FUS technique enhanced the anti-epileptic efficacy of PHT in a chronic mTLE rodent model by region-specific PPB disruption.

The Role of Activated Charcoal in Prehospital Care

Background

Administration of a single-dose activated charcoal (SDAC) is an effective method used for gastric decontamination and for other types of poisoning and overdose. This is only true when given within the first hour of poison ingestion as the effectivity of SDAC reduces over time. In addition, generally, not all patients are able to avail treatment within the specified period. Hence, multi-dose activated charcoal is regarded as a solution to a delayed process, although, no proof outweighs the use of SDAC.

Objective

This study aimed to review and assess the adequacy of the past and current use of AC. The author also aimed to offer recommendations believed to be the best method to consider for prehospital care.

Methods

The author conducted 6,337 online literature searches for this review, wherein seven papers met eligibility criteria for inclusion and analysis.

Results

In this review, routine administration of AC in poisoning was found not related to the duration of hospital stay nor any other subsequent outcomes following poison ingestion. Further, this review did not establish that administration of AC could improve patient's clinical outcome. Further research and clinical trials is required to determine the efficacy of this therapy to appropriate patients in the prehospital setting.

Conclusion

Activated charcoal can be used to treat highly acute to life-threatening poisoning if it is administered within the first hour of ingestion. Further studies would be necessary to investigate if this would affect clinical outcome..

Phenytoin-associated movement disorder: A literature review

Phenytoin (PHT) was first synthesized as a barbiturate derivative and was approved in 1953 by the Food and Drug Administration. This work aimed to review the pathophysiology, epidemiology, clinical presentation, and treatment of PHT-associated movement disorders (MDs). Studies were searched in relevant databases (ScienceDirect, Google Scholar, Excerpta Medica, Latin American and Caribbean Health Sciences Literature, Medline, and Scientific Electronic Library Online) and were selected by two reviewers irrespective of language between 1963 and 2021. Papers of PHT-induced ataxia alone or tremor were excluded. In total, 127 reports with 219 individuals who developed MDs associated with PHT were encountered. MDs found: 126 dyskinesias, 49 myoclonus, 19 dystonia, 14 parkinsonism, 6 tics, 3 stuttering, and 2 restless legs syndrome. The mean age was 35 years (standard deviation [SD]: 23.5) and the predominant sex was male (53.4%). The mean PHT dose when the MD took place was 370.4 mg (SD: 117.5). A serum PHT concentration was reported in 103 cases, ranging from 4 to 110 μg/mL (median: 27.7 μg/mL). No significant relationship was found between PHT dose and age or PHT level. The mean onset time of PHT-associated MD was 23.4 months (SD: 4.4). The mean recovery time after MD management was 3.7 weeks (SD: 1.1). Regarding management, the most common form was PHT withdrawal in 90.4%. 86.3% of the individuals recovered fully. PHT-induced MD was extensively reported in the literature. Only general terms were used in the majority of the reports. The mechanisms underlying the adverse events caused by PHT probably depend on the presence of predisposing factors.

Phenytoin as seizure prophylaxis in hematopoietic stem cell transplantation with busulfan conditioning

Background

Phenytoin is widely used as primary seizure prophylaxis in hematopoietic stem cell transplantation in patients undergoing myeloablative conditioning with busulfan. Because of the negative side effects of phenytoin, we abandoned phenytoin use in these patients. To assess the effect of this change, we performed a retrospective cohort study on all patients receiving busulfan.

Methods

We included 139 patients who underwent conditioning with busulfan for hematopoietic stem cell therapy. We registered the use of phenytoin, as well as the occurrence of seizures, until 7 days after busulfan administration. We compared seizure incidence between patients who received phenytoin and those who did not.

Results

Of the 43 patients who received phenytoin prophylaxis, four patients (9.3%) had a seizure during the conditioning regimen, of which two patients had cerebral non-Hodgkin lymphoma. Furthermore, all these 4 patients had very high levels of phenytoin (intoxication). Of the 96 patients that did not receive phenytoin prophylaxis, three patients (3.1%) had a seizure, and one of these patients had an undefined cerebral lesion. Phenytoin did not relate to seizure prevention in a logistic regression analysis.

Conclusion

We conclude that phenytoin prophylaxis in patients treated with busulfan is obsolete and possibly harmful, as phenytoin intoxication can occur. We recommend discontinuing the use of phenytoin as primary seizure prophylaxis in these patients.

A Rare Case of Junctional Bradycardia Secondary to Oral Phenytoin

Phenytoin is a commonly used anti-seizure agent, which stabilizes neuronal membranes by blocking voltage-gated sodium channels to inhibit the propagation of action potentials during convulsions. However, phenytoin has also been shown to have antiarrhythmic effects as it can prolong the effective refractory period of ventricular pacemaker cells. Adverse cardiac effects such as junctional bradycardia are usually seen with intravenous use. Cardiovascular dysfunction is not well recognized in oral phenytoin toxicity. Here we present a case of junctional bradycardia due to oral phenytoin toxicity, which resolved spontaneously with the discontinuation of phenytoin. This case report will serve to increase awareness of the adverse cardiovascular effects of oral phenytoin toxicity to improve the recognition and treatment of these adverse effects.

Correlation between Level of Serum Transaminases and Duration of Antiepileptic Drugs in Epilepsy Children in Sanglah Hospital

BACKGROUND: Some antiepileptic drugs (AEDs), particularly sodium valproate, phenytoin, phenobarbital, and carbamazepine induce and increase production of hepatic enzymes. The adverse metabolic effects of AEDs treatments have become main concern, however data about evaluation of serum transaminases and duration of AEDs in Indonesia still limited. AIM: The aim of the study was to investigate correlation of AEDs and serum transaminases in children with epilepsy. METHODS: This cross-sectional research was conducted in pediatric neurology outpatient clinic in Sanglah Hospital. The target was children with epilepsy who had taken AEDs for at least 6 months. Data were collected from January 2020 to the number of samples were achieved. The exclusion criteria were concomitant liver disease, taking drugs which induce elevated serum transaminase or alcohol abuse. Data including age, gender, nutritional status, type, and duration of AEDs were obtained from medical record. Correlation was analyzed by Pearson’s or Spearman’s correlation, p < 0.05 was considered significant. RESULTS: Total 148 epileptic children enrolled in this study. Aspartate transaminase (AST) and alanine aminotransferase (ALT) level were highest in the group receiving combination therapy (34.37 ± 24.9 U/L and 35.96 ± 23.3 U/L). There was a significant negative correlation between duration of carbamazepine and AST (r = –0.723, p = 0.0001) and ALT (r = –0.457, p = 0.009), as well as duration of valproic acid with AST and ALT (r = –0.689 and –0.677, p = 0.0001). Duration of phenobarbital administration was positively correlated with AST and ALT (r = 0.546 and 0.425, p = 0.0001). Combination therapy also had positive correlation with AST and ALT (r = 0.815 and 0.781, p = 0.0001, respectively). CONCLUSION: Duration administration of carbamazepine and valproic acid had negative correlation with AST and ALT; however, phenobarbital and combination therapy were positively correlated with AST and ALT.

Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction

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.

Super-Refractory Status Epilepticus: Prognosis and Recent Advances in Management

Super-refractory status epilepticus (SRSE) is a life-threatening neurological emergency with high morbidity and mortality. It is defined as “status epilepticus (SE) that continues or recurs 24 hours or more after the onset of anesthesia, including those cases in which SE recurs on the reduction or withdrawal of anesthesia.” This condition is resistant to normal protocols used in the treatment of status epilepticus and exposes patients to increased risks of neuronal death, neuronal injury, and disruption of neuronal networks if not treated in a timely manner. It is mainly seen in patients with severe acute onset brain injury or presentation of new-onset refractory status epilepticus (NORSE). The mortality, neurological deficits, and functional impairments are significant depending on the duration of status epilepticus and the resultant brain damage. Research is underway to find the cure for this devastating neurological condition. In this review, we will discuss the wide range of therapies used in the management of SRSE, provide suggestions regarding its treatment, and comment on future directions. The therapies evaluated include traditional and alternative anesthetic agents with antiepileptic agents. The other emerging therapies include hypothermia, steroids, immunosuppressive agents, electrical and magnetic stimulation therapies, emergent respective epilepsy surgery, the ketogenic diet, pyridoxine infusion, cerebrospinal fluid drainage, and magnesium infusion. To date, there is a lack of robust published data regarding the safety and effectiveness of various therapies, and there continues to be a need for large randomized multicenter trials comparing newer therapies to treat this refractory condition.

Rapid infusion of excessive phenytoin: A newborn autopsy case

The patient was a two-day-old female infant. The patient's mother was a primigravid in her 20 s who developed premature abruption of the normal placenta on the first day of the 33rd week of gestation. The infant was born by emergency cesarean section with severe neonatal asphyxia with a birth weight of 1928 g. Spontaneous circulation was returned 11 min after birth. The infant was treated under mechanical ventilation in the neonatal intensive care unit, and phenobarbital was administered for repeated seizures. On day 2, spontaneous respiration was observed; however, the patient developed seizures repeatedly. The dose of phenobarbital reached the maximum and was switched to midazolam. In the early morning of day 3, while midazolam was administered up to the maximum dose, the infant developed status epilepticus, and the anticonvulsant drug was changed to phenytoin. Due to a calculation error, the intravenous administration of phenytoin was started at 400 mg/30 min, which is 10-fold of the normal dose. Six minutes later, after 80 mg was administered, the administration was stopped due to a drop in blood pressure; however, the infant died of cardiac arrest. An autopsy, which was performed approximately 25 h after death, revealed the blood phenytoin concentration in the heart was 63.85 μg/mL. The cause of death was determined to be acute phenytoin toxicity. This is the first fatal case reported of the blood concentration of phenytoin caused by rapid intravenous administration.

Spectroscopic, density functional theoretical study, molecular docking, and in vitro studies based on anticancer activity studies against A549 lung cancer cell line of diphenylhydantoin adsorbed on AuNPs surface

The optimized geometry, FT-Raman, FT-IR, surface-enhanced Raman scattering, UV-Vis spectra, frontier molecular orbital analysis, molecular electrostatic potential analysis, and local and global reactivity descriptors of diphenylhydantoin (DPH) and diphenylhydantoin@AuNPs (DPHA) molecule have been investigated with the help of density functional theory method (B3LYP/6-31++G [d,p] together with LANL2DZ) and was compared and analyzed with the corresponding experimental data in order to identify their structural and bonding features responsible for their bioactivity. In-silico (molecular docking) biological activity screening of the molecules together with the in-vitro (SERS and MTT assay) analysis confirms the anticancer activity of DPH and DPHA molecules. The results of the structure-activity studies and bioactivity studies signify that the DPHA molecule is more active than the DPH molecule against lung cancer.

Levetiracetam for convulsive status epilepticus in childhood: systematic review and meta-analysis

IMPORTANCE

Prolonged seizures are life-threatening emergencies associated with significant morbidity.

OBJECTIVE

To determine the efficacy and safety of levetiracetam in treating convulsive status epilepticus (CSE) in childhood.

DATA SOURCES AND STUDY SELECTIONS

PubMed, Embase, the Cochrane Central Register of Controlled Trials and Cumulative Index to Nursing and Allied Health Literature were searched from inception up to April 2020. Only randomised controlled trials (RCTs) that included children aged 1 month-18 years were assessed. Two reviewers performed data assessment and extraction.

DATA EXTRACTION AND SYNTHESIS

Ten studies out of the 20 637 citations identified were included.

MAIN OUTCOMES

Cessation of seizure activities, time to cessation of seizure activities, need for rapid sequence intubation (RSI), intensive care unit (ICU) admission, recurrence of seizures at 24 hours, adverse events and all-cause mortality.

RESULTS

We included 10 RCTs (n=1907). There was no significant difference in cessation of seizure activities when levetiracetam was compared with phenytoin (risk ratio (RR)=1.03, 95% CI 0.98 to 1.09), levetiracetam to fosphenytoin (RR=1.16, 95% CI 1.00 to 1.35) or levetiracetam to valproate (RR=1.10, 95% CI 0.94 to 1.27). No differences were found in relation to the timing of cessation of seizures for levetiracetam versus phenytoin (mean difference (MD)=-0.45, 95% CI -1.83 to 0.93), or levetiracetam versus fosphenytoin (MD=-0.70, 95% CI -4.26 to 2.86). There were no significant differences with regard to ICU admissions, adverse events, recurrence of seizure at 24 hours, RSI and all-cause mortality.

CONCLUSION

Levetiracetam is comparable to phenytoin, fosphenytoin and valproate as a second line treatment of paediatric CSE.

[Efficacy and safety of levetiracetam versus phenytoin as second-line drugs for the treatment of children with convulsive status epilepticus: a Meta analysis]

OBJECTIVE

To systematically evaluate the efficacy and safety of levetiracetam (LEV) versus phenytoin (PHT) as second-line drugs for the treatment of convulsive status epilepticus (CSE) in children.

METHODS

English and Chinese electronic databases were searched for the randomized controlled trials comparing the efficacy and safety of LEV and PHT as second-line drugs for the treatment of childhood CSE. RevMan 5.3 software was used for data analysis.

RESULTS

Seven studies with 1 434 children were included. The Meta analysis showed that compared with the PHT group, the LEV group achieved a significantly higher control rate of CSE (RR=1.12, 95%CI:1.00-1.24, P=0.05), but there was no significant difference between the two groups in the recurrence rate of epilepsy within 24 hours (RR=0.82, 95%CI:0.22-3.11, P=0.77) and the rate of further antiepileptic drug therapy (RR=0.97, 95%CI:0.64-1.45, P=0.87). There was no significant difference in the incidence rate of adverse events between the two groups (RR=0.77, 95%CI:0.55-1.09, P=0.15).

CONCLUSIONS

LEV has a better clinical effect than PHT in the treatment of children with CSE and does not increase the incidence rate of adverse events.

Effect of Chronic Administration of 5-(3-chlorophenyl)-4-Hexyl-2,4 -Dihydro-3H-1,2,4-Triazole-3-Thione (TP-315)-A New Anticonvulsant Drug Candidate-On Living Organisms

About 70 million people suffer from epilepsy—a chronic neurodegenerative disease. In most cases, the cause of the disease is unknown, but epilepsy can also develop as the result of a stroke, trauma to the brain, or the use of psychotropic substances. The treatment of epilepsy is mainly based on the administration of anticonvulsants, which the patient must most often use throughout their life. Despite significant progress in research on antiepileptic drugs, about 30% of patients still have drug-resistant epilepsy, which is insensitive to pharmacotherapy used so far. In our recent studies, we have shown that 4-alkyl-5-aryl-1,2,4-triazole-3-thiones act on the voltage-gated sodium channels and exhibit anticonvulsant activity in an MES (maximal electroshock-induced seizure) and 6Hz test in mice. Previous studies have shown their beneficial toxic and pharmacological profile, but their effect on a living organism during chronic use is still unknown. In the presented study, on the basis of the previously conducted tests and the PAMPA (parallel artificial membrane permeability assay) BBB (blood–brain barrier) test, we selected one 1,2,4-triazole-3-thione derivative—TP-315—for further studies aimed at assessing the impact of its chronic use on a living organism. After long-term administration of TP-315 to Albino Swiss mice, its effect on the functional parameters of internal organs was assessed by performing biochemical, morphological, and histopathological examinations. It was also determined whether the tested compound inhibits selected isoforms of the CYP450 enzyme system. On the basis of the conducted tests, it was found that TP-315 does not show nephrotoxic nor hepatotoxic effects and does not cause changes in hematological parameters. In vitro tests showed that TP-315 did not inhibit CYP2B6, CYP2D6, CYP3A4, or CYP3A5 enzymes at the concentration found in the serum of mice subjected to long-term exposure to this compound.

Irreversible Cerebellar Atrophy as a Complication of Short-Term Phenytoin Exposure: Clinical Improvement Following Discontinuation of the Culprit

Phenytoin (diphenylhydantoin) is a widely used antiepileptic drug for controlling both generalized and partial seizures. Reversible cerebellar symptoms, including cerebellar ataxia, have been recognized as an adverse event of phenytoin use for many years. On the other hand, cerebellar degeneration has been reported with chronic use in an epileptic patient treated with this drug. We are reporting an interesting case of phenytoin induced acute pan-cerebellar syndrome with cerebellar atrophy on neuro-imaging that improved many years after discontinuation of the drug. Discontinuation of phenytoin may give a chance for the patient to recover slowly, months after stopping the drug. It is very important for the attending neurologist to educate the patients and their families on some common clinical manifestations suggestive of drug toxicity and perform a regular follow-up and clinical examination at regular intervals.

Cerebellar Degeneration in Epilepsy: A Systematic Review

Introduction: Cerebellar degeneration has been associated in patients with epilepsy, though the exact pathogenic mechanisms are not understood. The aim of this systematic review was to identify the prevalence of cerebellar degeneration in patients with epilepsy and identify any pathogenic mechanisms. Methodology: A systematic computer-based literature search was conducted using the PubMed database. Data extracted included prevalence, clinical, neuroradiological, and neuropathological characteristics of patients with epilepsy and cerebellar degeneration. Results: We identified three consistent predictors of cerebellar degeneration in the context of epilepsy in our review: temporal lobe epilepsy, poor seizure control, and phenytoin as the treatment modality. Whole brain and hippocampal atrophy were also identified in patients with epilepsy. Conclusions: Cerebellar degeneration is prevalent in patients with epilepsy. Further prospective studies are required to confirm if the predictors identified in this review are indeed linked to cerebellar degeneration and to establish the pathogenic mechanisms that result in cerebellar insult.

Levetiracetam as an alternative to phenytoin for second-line emergency treatment of children with convulsive status epilepticus: the EcLiPSE RCT

BACKGROUND

Convulsive status epilepticus is the most common neurological emergency in children. Its management is important to avoid or minimise neurological morbidity and death. The current first-choice second-line drug is phenytoin (Epanutin, Pfizer Inc., New York, NY, USA), for which there is no robust scientific evidence.

OBJECTIVE

To determine whether phenytoin or levetiracetam (Keppra, UCB Pharma, Brussels, Belgium) is the more clinically effective intravenous second-line treatment of paediatric convulsive status epilepticus and to help better inform its management.

DESIGN

A multicentre parallel-group randomised open-label superiority trial with a nested mixed-method study to assess recruitment and research without prior consent.

SETTING

Participants were recruited from 30 paediatric emergency departments in the UK.

PARTICIPANTS

Participants aged 6 months to 17 years 11 months, who were presenting with convulsive status epilepticus and were failing to respond to first-line treatment.

INTERVENTIONS

Intravenous levetiracetam (40 mg/kg) or intravenous phenytoin (20 mg/kg).

MAIN OUTCOME MEASURES

Primary outcome - time from randomisation to cessation of all visible signs of convulsive status epilepticus. Secondary outcomes - further anticonvulsants to manage the convulsive status epilepticus after the initial agent, the need for rapid sequence induction owing to ongoing convulsive status epilepticus, admission to critical care and serious adverse reactions.

RESULTS

Between 17 July 2015 and 7 April 2018, 286 participants were randomised, treated and consented. A total of 152 participants were allocated to receive levetiracetam and 134 participants to receive phenytoin. Convulsive status epilepticus was terminated in 106 (70%) participants who were allocated to levetiracetam and 86 (64%) participants who were allocated to phenytoin. Median time from randomisation to convulsive status epilepticus cessation was 35 (interquartile range 20-not assessable) minutes in the levetiracetam group and 45 (interquartile range 24-not assessable) minutes in the phenytoin group (hazard ratio 1.20, 95% confidence interval 0.91 to 1.60; p = 0.2). Results were robust to prespecified sensitivity analyses, including time from treatment commencement to convulsive status epilepticus termination and competing risks. One phenytoin-treated participant experienced serious adverse reactions.

LIMITATIONS

First, this was an open-label trial. A blinded design was considered too complex, in part because of the markedly different infusion rates of the two drugs. Second, there was subjectivity in the assessment of 'cessation of all signs of continuous, rhythmic clonic activity' as the primary outcome, rather than fixed time points to assess convulsive status epilepticus termination. However, site training included simulated demonstration of seizure cessation. Third, the time point of randomisation resulted in convulsive status epilepticus termination prior to administration of trial treatment in some cases. This affected both treatment arms equally and had been prespecified at the design stage. Last, safety measures were a secondary outcome, but the trial was not powered to demonstrate difference in serious adverse reactions between treatment groups.

CONCLUSIONS

Levetiracetam was not statistically superior to phenytoin in convulsive status epilepticus termination rate, time taken to terminate convulsive status epilepticus or frequency of serious adverse reactions. The results suggest that it may be an alternative to phenytoin in the second-line management of paediatric convulsive status epilepticus. Simple trial design, bespoke site training and effective leadership were found to facilitate practitioner commitment to the trial and its success. We provide a framework to optimise recruitment discussions in paediatric emergency medicine trials.

FUTURE WORK

Future work should include a meta-analysis of published studies and the possible sequential use of levetiracetam and phenytoin or sodium valproate in the second-line treatment of paediatric convulsive status epilepticus.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN22567894 and European Clinical Trials Database EudraCT number 2014-002188-13.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 58. See the NIHR Journals Library website for further project information.

Toxin-Induced Cerebellar Disorders

The cerebellum plays an important role in motor and nonmotor systems, with damage resulting in clinical manifestations presenting as weakness, ataxia, dysarthria, and nystagmus. There are numerous environmental and industrial agents as well as medications that, through either accidental or intentional use, can result in a range of neurologic presentations. The variability in the presentation is important to recognize promptly so that early cessation in exposure, use, or abuse can be initiated to reduce the severity of symptoms. Recognition of an agent causing the particular pathology is important so that the route of exposure, and subsequent treatment options can be identified.

36-year-old Male with Syncope

CASE PRESENTATION

A 36-year-old incarcerated male presented to the emergency department (ED) after an episode concerning for syncope. The patient had nystagmus and ataxia on initial examination.

DISCUSSION

There is a broad differential diagnosis for syncope, and for patients presenting to the ED we tend to focus on cardiogenic and neurologic causes. This case takes the reader through the differential diagnosis and systemic work-up of a patient presenting to the ED with syncope.

Use of phenytoin for treatment of tacrolimus toxicity with superimposed sepsis

A 40-year-old woman with a history of chronic graft-versus-host-disease on immunosuppression with tacrolimus presented to the hospital with somnolence, confusion and muscle cramps over a few days. She was found to have hypertension, hyperglycaemia and acute kidney injury with an elevated blood tacrolimus level of greater than 120 ng/mL (reference range 5-15 ng/mL). Discontinuation of tacrolimus with concomitant administration of intravenous phenytoin led to the successful reduction of elevated tacrolimus concentrations and the resolution of her symptoms. Tacrolimus is metabolised by the cytochrome P (CYP) 450 3A enzyme system, and utilisation of CYP 3A inducers to accelerate its clearance may be used as a successful therapy to treat tacrolimus toxicity.

Phenytoin - An anti-seizure drug: Overview of its chemistry, pharmacology and toxicology

Phenytoin is a long-standing, anti-seizure drug widely used in clinical practice. It has also been evaluated in the context of many other illnesses in addition to its original epilepsy indication. The narrow therapeutic index of phenytoin and its ubiquitous daily use pose a high risk of poisoning. This review article focuses on the chemistry, pharmacokinetics, and toxicology of phenytoin, with a special focus on its mutagenicity, carcinogenicity, and teratogenicity. The side effects on human health associated with phenytoin use are thoroughly described. In particular, DRESS syndrome and cerebellar atrophy are addressed. This review will help in further understanding the benefits phenytoin use in the treatment of epilepsy.

A CMOS MEMS-based Membrane-Bridge Nanomechanical Sensor for Small Molecule Detection

Small molecule compounds are necessary to detect with high sensitivity since they may cause a strong effect on the human body even in small concentrations. But existing methods used to evaluate small molecules in blood are inconvenient, costly, time-consuming, and do not allow for portable usage. In response to these shortcomings, we introduce a complementary metal-oxide-semiconductor bio-microelectromechanical system (CMOS BioMEMS) based piezoresistive membrane-bridge (MB) sensor for detecting small molecule (phenytoin) concentrations as the demonstration. Phenytoin is one of anticonvulsant drugs licensed for the management of seizures, which has a narrow therapeutic window hence a level of concentration monitoring was needed. The MB sensor was designed to enhance the structural stability and increase the sensitivity, which its signal response increased 2-fold higher than that of the microcantilever-based sensor. The MB sensor was used to detect phenytoin in different concentrations from 5 to 100  μg/mL. The limit of detection of the sensor was 4.06 ± 0.15  μg/mL and the linear detection range was 5–100  μg/mL, which was within the therapeutic range of phenytoin concentration (10–20  μg/mL). Furthermore, the MB sensor was integrated with an on-chip thermal effect eliminating modus and a reaction tank on a compact chip carrier for disposable utilization. The required amount of sample solution was only 10  μL and the response time of the sensor was about 25  minutes. The nano-mechanical MB sensing method with thermal effect compensation is specific, sensitive, robust, affordable and well reproducible; it is, therefore, an appropriate candidate for detecting small molecules.

Nanocage encapsulation improves antiepileptic efficiency of phenytoin

More than 30% of patients with epilepsy progress to drug-resistant epilepsy, leading to a significant increase in morbidity and mortality of epilepsy. The limitation of epileptic drug to reach the epileptogenic focus is the critical reason, and the blood-brain barrier (BBB) plays a crucial role. Here, we successfully constructed a hepatitis B core (HBc) protein nanocage (NC) with the insertion of brain target TGN peptide for facilitating epileptic drug phenytoin delivery to the brain. Our results demonstrated that this nanocage can specifically and efficiently target the brain tissue by 2.4 fold and increase the antiepileptic efficiency of phenytoin about 100 fold in pilocarpine induced models of epilepsy. Both in vivo mice and in vitro human neural three-dimensional cortical organoids demonstrated high penetration ability. These functions are achieved through the facilitation of brain target peptide TGN rather than disruption of brain blood barrier. In summary, we presented an efficient antiepileptic drug delivery nanocage for the treatment of refractory epilepsy. Moreover, this therapeutic modulation also provides promising strategy for other intractable neurological disease.

Phenytoin-Induced Paradoxical Seizures and Blood Dyscrasias in a Patient Receiving Rapid Intravenous Infusion: A Case Report

Paradoxical seizure is an unusual reaction of seizure aggravation or change in its pattern due to antiepileptics. Decrease in seizure threshold with phenytoin is bound to occur with an increase in serum levels. We herein report a 51-year-old female, who was brought to the intensive care unit with complaints of episodic seizures and frothing. She is a known case of tonic-clonic epilepsy on oral phenytoin 100 mg for past 6 months. Rapid intravenous infusion of 700 mg phenytoin in 100 mL normal saline over a rate of 15 minutes was initiated on admission. This was followed by a sudden abnormality of her baseline blood parameters and an occurrence of paradoxical seizure. The dose of phenytoin was tapered which reversed her condition. The patient was followed up regularly and monitored for fluctuations in her hematological parameters. The mainstay treatment for phenytoin-induced paradoxical seizure and blood dyscrasias is to monitor the patient and dose titration. Dosing of phenytoin remains a challenge for all clinicians which increase the need for such reports.

Cardiac Collapse Secondary to Phenytoin Toxicity in a Neonate Treated with Extracorporeal Membrane Oxygenation Support (ECMO)

INTRODUCTION

Although medication toxicity is uncommon in neonates, there are several medications used in this population that pose a risk. Phenytoin has an increased risk of toxicity given its narrow therapeutic window and variations in drug elimination.

CASE REPORT

We describe the case of a 3-day-old male infant who developed cardiovascular collapse secondary to severe phenytoin toxicity (max phenytoin level 86 μg/mL) and was placed on extracorporeal membrane oxygenation support (ECMO). Several ancillary treatments were utilized in an attempt to decrease serum phenytoin concentrations and limit toxicity including albumin boluses, phenobarbital administration, intravenous lipid infusion, and folic acid supplementation.

DISCUSSION

Although uncommon, drug toxicity should be considered in patients with acute changes who are exposed to medications with potential toxicity. With elevated levels of phenytoin, the half-life can be prolonged resulting in longer exposure to elevated levels of the drug as seen in our patient. This case report highlights the importance of ECMO utilization for cardiac support in neonates with medication toxicity and other potential ancillary treatments to decrease serum phenytoin concentrations.

Levetiracetam versus phenytoin for second-line treatment of paediatric convulsive status epilepticus (EcLiPSE): a multicentre, open-label, randomised trial

BACKGROUND

Phenytoin is the recommended second-line intravenous anticonvulsant for treatment of paediatric convulsive status epilepticus in the UK; however, some evidence suggests that levetiracetam could be an effective and safer alternative. This trial compared the efficacy and safety of phenytoin and levetiracetam for second-line management of paediatric convulsive status epilepticus.

METHODS

This open-label, randomised clinical trial was undertaken at 30 UK emergency departments at secondary and tertiary care centres. Participants aged 6 months to under 18 years, with convulsive status epilepticus requiring second-line treatment, were randomly assigned (1:1) using a computer-generated randomisation schedule to receive levetiracetam (40 mg/kg over 5 min) or phenytoin (20 mg/kg over at least 20 min), stratified by centre. The primary outcome was time from randomisation to cessation of convulsive status epilepticus, analysed in the modified intention-to-treat population (excluding those who did not require second-line treatment after randomisation and those who did not provide consent). This trial is registered with ISRCTN, number ISRCTN22567894.

FINDINGS

Between July 17, 2015, and April 7, 2018, 1432 patients were assessed for eligibility. After exclusion of ineligible patients, 404 patients were randomly assigned. After exclusion of those who did not require second-line treatment and those who did not consent, 286 randomised participants were treated and had available data: 152 allocated to levetiracetam, and 134 to phenytoin. Convulsive status epilepticus was terminated in 106 (70%) children in the levetiracetam group and in 86 (64%) in the phenytoin group. Median time from randomisation to cessation of convulsive status epilepticus was 35 min (IQR 20 to not assessable) in the levetiracetam group and 45 min (24 to not assessable) in the phenytoin group (hazard ratio 1·20, 95% CI 0·91-1·60; p=0·20). One participant who received levetiracetam followed by phenytoin died as a result of catastrophic cerebral oedema unrelated to either treatment. One participant who received phenytoin had serious adverse reactions related to study treatment (hypotension considered to be immediately life-threatening [a serious adverse reaction] and increased focal seizures and decreased consciousness considered to be medically significant [a suspected unexpected serious adverse reaction]).

INTERPRETATION

Although levetiracetam was not significantly superior to phenytoin, the results, together with previously reported safety profiles and comparative ease of administration of levetiracetam, suggest it could be an appropriate alternative to phenytoin as the first-choice, second-line anticonvulsant in the treatment of paediatric convulsive status epilepticus.

FUNDING

National Institute for Health Research Health Technology Assessment programme.

Phenytoin-induced hypothermia

A 60-year-old man with cerebral palsy and epilepsy was admitted with acute lethargy and deterioration in coordination. He was noted to be hypothermic at 35°C on admission. Routine work-up revealed toxic levels of phenytoin. No cause of hypothermia could be identified but as his phenytoin levels normalised, his body temperature also improved. There are three other reported cases of phenytoin- induced hypothermia in the literature. Could this be a rare cause of hypothermia?

A systematic review of phenytoin intoxication induced by compound phenytoin sodium, ephedrine hydrochloride and theophylline tablets in China

OBJECTIVE

In this study, we aimed to review the literature on phenytoin intoxication induced by compound phenytoin sodium, ephedrine hydrochloride and theophylline tablets (CPEHTT).

METHOD

A literature search was performed in the following databases: WANFANG DATA, HowNet, National Library Reference and Consultation Alliance, Full-text Database of Foreign Medical Journals, PubMed and Ovid. The search terms were "Compound Phenytoin Sodium, ephedrine Hydrochloride and Theophylline Tablets," and "poisoning," or "toxicity," in Chinese and in English.

RESULT

Ten articles including 104 patients with CPEHTT intoxication were identified. The ages of the patients ranged from 52 to 82 years. Sixty-seven patients were male and thirty-seven patients were female (the male/female ratio, approximately 2:1). The most common clinical manifestations were dizziness (85%) and ataxia (85%), followed by limb weakness (65%), diplopia (25%), binocular horizontal nystagmus (24%), limb numbness (13%), nausea and vomiting (12%), somnolence (10%), tremor and high muscle tension (7%), lag in response (5%), dysarthria (6%), choking cough (2%), auditory hallucination and visual fantasy (1%), and involuntary movement (1%). All patients had chronic lung disease, and the most common disease was chronic bronchitis. The dosage ranged 4 to 15 tablets per day with medication duration of more than 1 year for most patients.

CONCLUSION

The CPEHTT intoxication caused by phenytoin toxicity represents a drug safety problem in China. The common clinical manifestations, serum phenytoin concentrations, and associated factors of CPEHTT intoxication are important for diagnosis and prevention. These findings may help guide clinicians to correctly attend to the use of CPEHTT and avoid its toxicity.

A new method for simultaneous quantification of fosphenytoin, phenytoin and its primary metabolite 5-(4-hydroxyphenyl)-5-phenylhydantoin in whole blood by ultra-performance liquid chromatography-tandem mass spectrometry

A method for simultaneous quantification of fosphenytoin (F-PHT), phenytoin (PHT) and its main metabolite 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) in whole blood was developed and validated using ultra-performance liquid chromatography-tandem mass spectrometry. Whole blood samples were pretreated by liquid-liquid extraction with acetonitrile and methanol. Chromatographic separation was performed using a CORTECS™ UPLC® C18 (2.1 × 50 mm i.d., particle size 1.6 μm) analytical column, and water containing 10 mM ammonium formate and acetonitrile as the mobile phase. Quantification of the analytes was carried out using mass chromatography with each product ion referenced against phenytoin-d₁₀ as an internal standard. Calibration curves exhibited good linear relationships in a range from 0.005 to 50 μg/ml with correlation coefficients exceeding 0.995. The limits of detection were estimated to be 0.002-0.01 μg/ml. The accuracies and precisions were 96.2-104.3% and 0.7-10.7%, respectively. The recovery efficiencies were in the range of 42.4-59.2%. Matrix effects were observed for PHT and HPPH, with signal suppression ranging from -6.6 to -32.2%. Matrix effect for F-PHT (-5.0 to 8.9%) was less than those for PHT and HPPH. All analytes were stable under different storage conditions. This method was successfully applied for the quantification of F-PHT, PHT and HPPH in rat whole blood samples taken after bolus intravenous administration of F-PHT.

Toxicological evaluation of convulsant and anticonvulsant drugs in human induced pluripotent stem cell-derived cortical neuronal networks using an MEA system

Functional evaluation assays using human induced pluripotent stem cell (hiPSC)-derived neurons can predict the convulsion toxicity of new drugs and the neurological effects of antiepileptic drugs. However, differences in responsiveness depending on convulsant type and antiepileptic drugs, and an evaluation index capable of comparing in vitro responses with in vivo responses are not well known. We observed the difference in synchronized burst patterns in the epileptiform activities induced by pentylentetrazole (PTZ) and 4-aminopryridine (4-AP) with different action mechanisms using multi-electrode arrays (MEAs); we also observed that 100 µM of the antiepileptic drug phenytoin suppressed epileptiform activities induced by PTZ, but increased those induced by 4-AP. To compare in vitro results with in vivo convulsive responses, frequency analysis of below 250 Hz, excluding the spike component, was performed. The in vivo convulsive firing enhancement of the high γ wave and β wave component were observed remarkably in in vitro hiPSC-derived neurons with astrocytes in co-culture. MEA measurement of hiPSC-derived neurons in co-culture with astrocytes and our analysis methods, including frequency analysis, appear effective for predicting convulsion toxicity, side effects, and their mechanism of action as well as the comparison of convulsions induced in vivo.

Emergency treatment with levetiracetam or phenytoin in status epilepticus in children-the EcLiPSE study: study protocol for a randomised controlled trial

Background

Convulsive status epilepticus (CSE) is the most common life-threatening neurological emergency in childhood. These children are also at risk of significant morbidity, with acute and chronic impact on the family and the health and social care systems. The current recommended first-choice, second-line treatment in children aged 6 months and above is intravenous phenytoin (fosphenytoin in the USA), although there is a lack of evidence for its use and it is associated with significant side effects. Emerging evidence suggests that intravenous levetiracetam may be effective as a second-line agent for CSE, and fewer adverse effects have been described. This trial therefore aims to determine whether intravenous phenytoin or levetiracetam is more effective, and safer, in treating childhood CSE.

Methods/design

This is a phase IV, multi-centre, parallel group, randomised controlled, open-label trial. Following treatment for CSE with first-line treatment, children with ongoing seizures are randomised to receive either phenytoin (20 mg/kg, maximum 2 g) or levetiracetam (40 mg/kg, maximum 2.5 g) intravenously. The primary outcome measure is the cessation of all visible signs of CSE as determined by the treating clinician. Secondary outcome measures include the need for further anti-seizure medications or rapid sequence induction for ongoing CSE, admission to critical care areas, and serious adverse reactions. Patients are recruited without prior consent, with deferred consent sought at an appropriate time for the family. The primary analysis will be by intention-to-treat. The primary outcome is a time to event outcome and a sample size of 140 participants in each group will have 80% power to detect an increase in CSE cessation rates from 60% to 75%. Our total sample size of 308 randomised and treated participants will allow for 10% loss to follow-up.

Discussion

This clinical trial will determine whether phenytoin or levetiracetam is more effective as an intravenous second-line agent for CSE, and provide evidence for management recommendations. In addition, this trial will also provide data on which of these therapies is safer in this setting.

Trial registration

ISRCTN identifier, ISRCTN22567894. Registered on 27 August 2015

EudraCT identifier, 2014-002188-13. Registered on 21 May 2014

NIHR HTA Grant: 12/127/134

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2010-8) contains supplementary material, which is available to authorized users.

Velopharyngeal Incoordination Caused by Phenytoin-Induced Toxicity

Phenytoin induces lymphoid proliferation, resulting in complications that can range from tissue hyperplasia to lymphoma. Some of the complications resolve spontaneously after drug discontinuation. This report describes for the first time a case of dysphagia with lack of velopharyngeal coordination and nasopharyngeal reflux combined with massive palatine tonsillar hypertrophy. The condition did not develop before phenytoin administration, was induced by phenytoin, and spontaneously resolved upon drug discontinuation. The patient was referred for a video-fluoroscopic swallowing study owing to a recurring nasal reflux of foods that had developed since phenytoin administration. The video-fluoroscopic swallowing study revealed incidentally that the large bilateral elongated masses extended downward into the larynx and disturbed velar elevation. This finding was confirmed by computed tomography of the neck, which showed that palatine tonsillar hypertrophy disturbed the laryngopharynx on both sides. The symptoms (sleep apnea and nasal reflux) and the abnormal imaging findings disappeared without surgery approximately 1 month after drug discontinuation. This case suggests that dysphagia related to phenytoin-induced lymphoid hypertrophy may be treated by phenytoin discontinuation followed by a sufficient amount of time to allow symptom resolution rather than by prompt surgery.

Should we do early and frequent charcoal hemoperfusion in phenytoin toxicity?

Phenytoin toxicity or adverse drug reaction is common due to its narrow therapeutic window. Mild and moderate toxicity require supportive care and enteral activated charcoal. In severe toxicity, charcoal hemoperfusion (CHP) have been shown to decrease serum phenytoin half-life and early recovery. Here, we report two cases with phenytoin toxicity who showed marked clinical improvement after early and frequent CHP treatment.

Remarkable Phenytoin Sensitivity in 4 Children with SCN8A-related Epilepsy: A Molecular Neuropharmacological Approach

Mutations in SCN8A are associated with epilepsy and intellectual disability. SCN8A encodes for sodium channel Nav1.6, which is located in the brain. Gain-of-function missense mutations in SCN8A are thought to lead to increased firing of excitatory neurons containing Nav1.6, and therefore to lead to increased seizure susceptibility. We hypothesized that sodium channel blockers could have a beneficial effect in patients with SCN8A-related epilepsy by blocking the overactive Nav1.6 and thereby counteracting the effect of the mutation. Herein, we describe 4 patients with a missense SCN8A mutation and epilepsy who all show a remarkably good response on high doses of phenytoin and loss of seizure control when phenytoin medication was reduced, while side effects were relatively mild. In 2 patients, repeated withdrawal of phenytoin led to the reoccurrence of seizures. Based on the findings in these patients and the underlying molecular mechanism we consider treatment with (high-dose) phenytoin as a possible treatment option in patients with difficult-to-control seizures due to an SCN8A mutation.

Cardiovascular adverse effects of phenytoin

Phenytoin is an established drug in the treatment of acute repetitive seizures and status epilepticus. One of its main advantages over benzodiazepines is the less sedative effect. However, the possibility of cardiovascular adverse effects with the intravenous use of phenytoin cause a reluctance to its usage, and this has lead to a search for safer anticonvulsant drugs. In this study, we aimed to review the studies which evaluated the safety of phenytoin with respect to cardiovascular adverse effects. The original clinical trials and case reports listed in PUBMED in English language between the years of 1946-2014 were evaluated. As the key words, "phenytoin, diphenylhydantoin, epilepsy, seizure, cardiac toxicity, asystole, arrhythmia, respiratory arrest, hypotension, death" were used. Thirty-two clinical trials and ten case reports were identified. In the case reports, a rapid infusion rate (>50 mg/min) of phenytoin appeared as the major cause of increased mortality. In contrast, no serious cardiovascular adverse effects leading to death were met in the clinical trials which applied the recommended infusion rate and dosages. An infusion rate of 50 mg/min was reported to be safe for young patients. For old patients and patients with a cardiovascular co-morbidity, a slower infusion rate was recommended with a careful follow-up of heart rhythm and blood pressure. No cardiovascular adverse effect was reported in oral phenytoin overdoses except one case with a very high serum phenytoin level and hypoalbuminemia. Phenytoin is an effective and well tolerated drug in the treatment of epilepsy. Intravenous phenytoin is safe when given at recommended infusion rates and doses.

Extracorporeal Treatment in Phenytoin Poisoning: Systematic Review and Recommendations from the EXTRIP (Extracorporeal Treatments in Poisoning) Workgroup

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.

Phenytoin toxicity from cocaine adulteration

The use of phenytoin (PHT) as a cocaine adulterant was reported decades ago; that practice is still current. Ironically PHT has also been used for the treatment of cocaine dependence. A drug smuggler developed PHT toxicity after swallowing several rocks of crack. We investigated the current trends of PHT as a cocaine adulterant and its toxicological implications. We also reviewed the clinical use of PTH in relation to cocaine. The use of PHT as cocaine cut is a current practice. This may affect the clinical manifestations and the management of the cocaine-related visits to the emergency department.

Life-threatening bradyarrhythmia with oral phenytoin overdose

We report a case of a 41-year-old lady, who developed severe hypotension and sinus bradycardia, following oral consumption of 20 g of phenytoin and 500 mg of glibenclamide. She required high dose of inotropes and a temporary transvenous pacer for her hemodynamic instability. This life-threatening cardiotoxicity of phenytoin could have been due to its interaction with sulphonylurea. It is imperative to be aware of drug interactions, due to which, life-threatening cardiovascular manifestations following phenytoin toxicity can occur.

Novel method for rapid reversal of drug toxicity: a case report

Drug toxicity is traditionally treated by reducing the amount of the drug absorbed, enhancing elimination, and providing supportive care. Once the drug has been absorbed, there are few methods that help decrease morbidity and mortality caused by a toxic drug level. Albumin infusion is a new approach that changes that, as it can rapidly reverse a toxic drug level back to a therapeutic level. It is believed with most drugs that the toxic effects are related to the total amount of the free drug. In this method, albumin binds to the free drug and acts as a reservoir or depot from which the drug is slowly released to the free form, thereby limiting the effects of drug toxicity. In this case report, an elderly female patient who experienced phenytoin toxicity was treated with albumin infusion, after which her phenytoin level returned to a therapeutic level with corresponding improvements in her symptoms. Based on our calculations, it was predicted that a small amount of albumin would reverse the patient's toxic symptoms. With this approach, the patient's toxic symptoms improved when free phenytoin levels dropped from 15 to 8 μmol/L. Albumin infusion is a promising new therapy that can rapidly reverse a toxic drug level back to a therapeutic level by binding the free drug to albumin.

Drug-induced cerebellar ataxia: a systematic review

BACKGROUND AND OBJECTIVES

Cerebellar ataxia can be induced by a large number of drugs. We here conducted a systemic review of the drugs that can lead to cerebellar ataxia as an adverse drug reaction (ADR).

METHODS

We performed a systematic literature search in Pubmed (1966 to January 2014) and EMBASE (1988 to January 2014) to identify all of the drugs that can have ataxia as an ADR and to assess the frequency of drug-induced ataxia for individual drugs. Furthermore, we collected reports of drug-induced ataxia over the past 20 years in the Netherlands by querying a national register of ADRs.

RESULTS

Drug-induced ataxia was reported in association with 93 individual drugs (57 from the literature, 36 from the Dutch registry). The most common groups were antiepileptic drugs, benzodiazepines, and antineoplastics. For some, the number needed to harm was below 10. Ataxia was commonly reversible, but persistent symptoms were described with lithium and certain antineoplastics.

CONCLUSIONS

It is important to be aware of the possibility that ataxia might be drug-induced, and for some drugs the relative frequency of this particular ADR is high. In most patients, symptoms occur within days or weeks after the introduction of a new drug or an increase in dose. In general, ataxia tends to disappear after discontinuation of the drug, but chronic ataxia has been described for some drugs.

Awake craniotomy for brain tumor: indications, technique and benefits

Increasing interest in the quality of life of patients after treatment of brain tumors has led to the exploration of methods that can improve intraoperative assessment of neurological status to avoid neurological deficits. The only method that can provide assessment of all eloquent areas of cerebral cortex and white matter is brain mapping during awake craniotomy. This method helps ensure that the quality of life and the neuro-oncological result of treatment are not compromised. Apart from the medical aspects of awake surgery, its economic issues are also favorable. Here, we review the main aspects of awake brain tumor surgery. Neurosurgical, neuropsychological, neurophysiological and anesthetic issues are briefly discussed.