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.

Efficacy of levetiracetam compared with phenytoin in prevention of seizures in brain injured patients: A meta-analysis

BACKGROUND

Early and/or late onset in patients with brain injury (BI) is associated with a poorer prognosis, and phenytoin (PHT) is standard of care to prevent seizures. Levetiracetam (LEV), an alternative antiepileptic drug, is associated with less cognitive disruption. The purpose of this study was to evaluate the safety and efficacy of LEV in the prevention of brain traumatic seizures with the standard drug PHT.

METHODS

Search the publications on comparison the safety and efficacy of LEV against the standard agent PHT in prevention of traumatic seizures in BI to January 2018. After rigorous reviewing on quality, the data were extracted from eligible trials. All trials analyzed the summary hazard ratios of the endpoints of interest.

RESULTS

LEV was found not more effective than PHT in terms of overall seizure (odds ratio [OR] = 0.73; 95% confidence interval [CI] = 0.51-1.05; P = .09), and late seizure (OR = 0.64; 95% CI = 0.34-1.19; P = .16) occurrence. However, there is significant difference in terms of early seizure (OR = 0.63; 95% CI = 0.40-0.99; P = .04). Moreover, there were no significant differences in terms of mortality (OR = 0.67; 95% CI = 0.43-1.05; P = .08), or side effects (OR = 1.31; 95% CI = 0.80-2.15; P = .29) between groups.

CONCLUSION

The meta-analysis showed that LEV prevention of seizures was associated with early seizure rates that were lower than the PHT-prolonged course of treatment. There is no statistically significant difference in the efficacy and safety profile of PHT and LEV in cases of traumatic BI.

Oxcarbazepine versus phenytoin monotherapy for epilepsy: an individual participant data review

BACKGROUND

This is an updated version of the Cochrane Review previously published in 2013. This review is one in a series of Cochrane Reviews investigating pair-wise monotherapy comparisons.Epilepsy is a common neurological condition in which abnormal electrical discharges from the brain cause recurrent unprovoked seizures. It is believed that with effective drug treatment, up to 70% of individuals with active epilepsy have the potential to become seizure-free and go into long-term remission shortly after starting drug therapy with a single antiepileptic drug in monotherapy.Worldwide, phenytoin is a commonly used antiepileptic drug. It is important to know how newer drugs, such as oxcarbazepine, compare with commonly used standard treatments.

OBJECTIVES

To review the time to treatment failure, remission and first seizure with oxcarbazepine compared to phenytoin, when used as monotherapy in people with focal onset seizures or generalised tonic-clonic seizures (with or without other generalised seizure types).

SEARCH METHODS

We searched the following databases on 20 August 2018: the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to 20 August 2018), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We handsearched relevant journals and contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

We included randomised controlled trials comparing monotherapy with either oxcarbazepine or phenytoin in children or adults with focal onset seizures or generalised onset tonic-clonic seizures.

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD) review. Our primary outcome was time to treatment failure and our secondary outcomes were time to first seizure post-randomisation, time to six-month and 12-month remission, and incidence of adverse events. We used Cox proportional hazards regression models to obtain trial-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs), using the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

Individual participant data were available for 480 out of a total of 517 participants (93%), from two out of three included trials. For remission outcomes, a HR of less than one indicated an advantage for phenytoin; and for first seizure and treatment failure outcomes, a HR of less than one indicated an advantage for oxcarbazepine.The results for time to treatment failure for any reason related to treatment showed a potential advantage of oxcarbazepine over phenytoin, but this was not statistically significant (pooled HR adjusted for epilepsy type: 0.78 95% CI 0.53 to 1.14, 476 participants, two trials, moderate-quality evidence). Our analysis showed that treatment failure due to adverse events occurred later on with oxcarbazepine than phenytoin (pooled HR for all participants: 0.22 (95% CI 0.10 to 0.51, 480 participants, two trials, high-quality evidence). Our analysis of time to treatment failure due to lack of efficacy showed no clear difference between the drugs (pooled HR for all participants: 1.17 (95% CI 0.31 to 4.35), 480 participants, two trials, moderate-quality evidence).We found no clear or statistically significant differences between drugs for any of the secondary outcomes of the review: time to first seizure post-randomisation (pooled HR adjusted for epilepsy type: 0.97 95% CI 0.75 to 1.26, 468 participants, two trials, moderate-quality evidence); time to 12-month remission (pooled HR adjusted for epilepsy type 1.04 95% CI 0.77 to 1.41, 468 participants, two trials, moderate-quality evidence) and time to six-month remission (pooled HR adjusted for epilepsy type: 1.06 95% CI 0.82 to 1.36, 468 participants, two trials, moderate-quality evidence).The most common adverse events reported in more than 10% of participants on either drug were somnolence (28% of total participants, with similar rates for both drugs), headache (15% of total participants, with similar rates for both drugs), dizziness (14.5% of total participants, reported by slightly more participants on phenytoin (18%) than oxcarbazepine (11%)) and gum hyperplasia (reported by substantially more participants on phenytoin (18%) than oxcarbazepine (2%)).The results of this review are applicable mainly to individuals with focal onset seizures; 70% of included individuals experienced seizures of this type at baseline. The two studies included in IPD meta-analysis were generally of good methodological quality but the design of the studies may have biased the results for the secondary outcomes (time to first seizure post-randomisation, time to six-month and 12-month remission) as seizure recurrence data were not collected following treatment failure or withdrawal from the study. In addition, misclassification of epilepsy type may have impacted on results, particularly for individuals with generalised onset seizures.

AUTHORS' CONCLUSIONS

High-quality evidence provided by this review indicates that treatment failure due to adverse events occurs significantly later with oxcarbazepine than phenytoin. For individuals with focal onset seizures, moderate-quality evidence suggests that oxcarbazepine may be superior to phenytoin in terms of treatment failure for any reason, seizure recurrence and seizure remission. Therefore, oxcarbazepine may be a preferable alternative treatment than phenytoin, particularly for individuals with focal onset seizures. The evidence in this review which relates to individuals with generalised onset seizures is of low quality and does not inform current treatment policy.We recommend that future trials should be designed to the highest quality possible with regards to choice of population, classification of seizure type, duration of follow-up (including continued follow-up after failure or withdrawal of randomised treatment), choice of outcomes and analysis, and presentation of results.

Hypothyroidism induced by phenytoin and gabapentin: A Case Report

RATIONALE

Antiepileptic drugs (AEDs) are one of the causative drugs of drug-induced hypothyroidism. In most cases, AED-induced hypothyroidism is subclinical and indicated only by abnormalities of free thyroxine (T4) and/or thyroid-stimulating hormone (TSH) levels. Severe symptomatic hypothyroidism following AEDs is rarely reported in the literature.

PATIENT CONCERNS

A 75-year-old man experienced neurologic symptoms including memory impairment, ataxic gait, sensory polyneuropathy and myopathy, lethargy, and edema of the face and lower extremities. He had been administered phenytoin and gabapentin for the treatment of symptomatic traumatic epilepsy 8 years before.

DIAGNOSES

The patient had low free T4 (0.21 ng/dL) and high TSH (113.2 μIU/mL), which indicated hypothyroidism. Negative thyroid-related autoantibody tests and the lack of goiter excluded the possibility of Hashimoto disease. Phenytoin and/or gabapentin were strongly suspected as causing his hypothyroidism.

INTERVENTION

The patient was treated with replacement therapy (levothyroxine 25 μg/day).

OUTCOMES

His symptoms markedly and promptly improved alongside continued antiepileptic therapy.

LESSONS

In this case, the patient's hypothyroidism was assumed to result from different mechanisms of the 2 AEDs leading to thyroid hormone reduction. AEDs can not only cause asymptomatic thyroid hormone abnormalities but also clinically observable hypothyroidism. Therefore, clinicians should be aware of the association between anticonvulsants and symptomatic hypothyroidism.

Analysis of phenytoin drug concentration for evaluation of clinical response, uncontrolled seizures and toxicity

The narrow therapeutic index, non-linear pharmacokinetics and unpredictable absorption require regular therapeutic monitoring of phenytoin. The influence of genetic differences, sex, age and race on the phenytoin plasma levels and its metabolites is well recognized. This study is aimed at evaluating phenytoin plasma drug concentration and its relationship with clinical response, persistent seizures and toxicity in different gender and various age groups of Chinese epileptic patients. This knowledge will help the clinicians in adjusting the drug dosages of phenytoin in various sub-groups of epileptic patients for enhancing the safety, efficacy and minimizing the toxicity of phenytoin. A total of 48 plasma samples of epileptic patients for measuring the plasma phenytoin concentration were received. Only patients displaying persistent seizures or suspected of adverse effects were requested for drug monitoring. All these samples were analyzed for therapeutic drug monitoring with Enzyme-multiplied immunoassay technique. Surprisingly, it was found that majorities (85.5%) of samples were out of the reference range, of which 69% of samples were in sub-therapeutic levels and 16.5% of samples were above therapeutic levels. Only 14.5% of all samples had phenytoin levels in the therapeutic range. The difference in plasma concentration of phenytoin was notably altered in gender and various age groups. Careful attention must be applied to specific gender and particular age group on an individual basis in the interpretation of plasma concentration results, in order to facilitate the modification of doses and develop the best approach in treatment and to obtain the desired clinical response because multiple factors can affect the phenytoin plasma concentration. Through these results, it can be concluded that a good correlation exists between phenytoin plasma concentration and clinical response. Therefore, regular therapeutic monitoring of phenytoin and screening of HLA-A, B, C and DRB1 genotypes before prescribing phenytoin in epileptic patients is essentially required to achieve maximum clinical response and prevent the serious toxicity.

HLH - Unusual Trigger and Positive Outcome

Hemophagocytic Lymphohistiocytosis (HLH), is an uncommon, aggressive and life threatening syndrome of excessive immune activation. We report an unusual case of HLH, in a 34 year old male, who was admitted with Subarachnoid hemorrhage and cerebellar contusion in a Neurosurgical Intensive care unit, whose trigger is not clear.

Genetic variation in CFH predicts phenytoin-induced maculopapular exanthema in European-descent patients

OBJECTIVE

To characterize, among European and Han Chinese populations, the genetic predictors of maculopapular exanthema (MPE), a cutaneous adverse drug reaction common to antiepileptic drugs.

METHODS

We conducted a case-control genome-wide association study of autosomal genotypes, including Class I and II human leukocyte antigen (HLA) alleles, in 323 cases and 1,321 drug-tolerant controls from epilepsy cohorts of northern European and Han Chinese descent. Results from each cohort were meta-analyzed.

RESULTS

We report an association between a rare variant in the complement factor H-related 4 (CFHR4) gene and phenytoin-induced MPE in Europeans (p = 4.5 × 10-11; odds ratio [95% confidence interval] 7 [3.2-16]). This variant is in complete linkage disequilibrium with a missense variant (N1050Y) in the complement factor H (CFH) gene. In addition, our results reinforce the association between HLA-A*31:01 and carbamazepine hypersensitivity. We did not identify significant genetic associations with MPE among Han Chinese patients.

CONCLUSIONS

The identification of genetic predictors of MPE in CFHR4 and CFH, members of the complement factor H-related protein family, suggest a new link between regulation of the complement system alternative pathway and phenytoin-induced hypersensitivity in European-ancestral patients.

Acute renal failure secondary to drug-related crystalluria and/or drug reaction with eosinophilia and systemic symptom syndrome in a patient with metastatic lung cancer

Drug reaction with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity is a severe adverse drug-induced reaction. Aromatic anticonvulsants, such as phenytoin, phenobarbital, and carbamazepine, and some drugs, can induce DRESS. Atypical crystalluria can be seen in patients treated with amoxycillin or some drugs and can cause acute renal failure. We describe a 66-year-old man who presented fever and rash and acute renal failure three days after starting amoxycillin. He was also using phenytoin because of cerebral metastatic lung cancer. Investigation revealed eosinophilia and atypical crystalluria. The diagnosis of DRESS syndrome was made, amoxicillin was stopped, and dose of phenytoin was reduced. No systemic corticosteroid therapy was prescribed. Symptoms began to resolve within three to four days. The aim of this paper is to highlight the importance of microscopic examination of urine in a case with acute renal failure and skin lesions to suspect DRESS syndrome.

Homocysteine Metabolism and Hematological Parameters in Early Stage of Phenytoin Treated Epileptic Children

BACKGROUND

Long-term antiepileptic drug (AED) therapy has been associated with metabolic consequences that lead to an increase in risk of atherosclerosis in patients with epilepsy. Earlier published studies showed conflicting results about the levels of hematological parameters, serum homocysteine, folate, and vitamin B12, in epileptics treated with phenytoin monotherapy. Therefore, we evaluated homocysteine metabolism and hematological parameters in early stage of phenytoin treated epileptic children.

METHODS

A total of 64 newly diagnosed epileptic children with mean age 10.09 ± 2.56 years were enrolled at the start of study. However, after 3 months follow up, the final total sample size was only 50 epileptic children. Fourteen children dropped out of study due to poor follow up. Serum homocysteine levels were measured by enzyme immunoassay method. Serum folate and vitamin B12 levels were estimated by Competitive Chemiluminescent Enzyme Immunoassay method. Hematological parameters were analysed by an automated hematology analyzer (Cell counter), Sysmex XT-1800i, using commercially available reagents.

RESULTS

In our study the anthropometric and hematological parameters did not show any significant difference after phenytoin monotherapy as compared to before therapy in epileptic children. The serum homocysteine level in epileptic children was found to be significantly increased after phenytoin (PHT) monotherapy as compared to before therapy. Moreover, a highly significant decrease was observed in the serum folate and vitamin B12 levels after phenytoin monotherapy as compared to before therapy in epileptic children.

CONCLUSIONS

Phenytoin monotherapy may cause a significant increase in the levels of serum homocysteine and a significant decrease in the serum folate and vitamin B12 levels in children with epilepsy, and the significant changes in above mentioned parameters occur early in the course of treatment. This could be responsible for a higher prevalence of cardiovascular incidents in epileptic children taking phenytoin monotherapy. Therefore, it may be useful to do early screening and treatment of increased serum homocysteine levels in epileptic children under phenytoin monotherapy to prevent atherosclerosis and its complications. Hematological parameters should also be strictly monitored regularly in individuals administered with PHT monotherapy. If there are persistent alterations, the administration of the drugs should be discontinued.

Efficacy of levetiracetam versus fosphenytoin for the recurrence of seizures after status epilepticus

Benzodiazepines are used as first-line treatments for status epilepticus. Fosphenytoin (FPHT) is recommended for second-line therapy; however, intravenous injection of levetiracetam (LEV) may also be effective against status epilepticus. Herein, we compared the efficacy and safety of LEV as a second-line treatment for status epilepticus with FPHT in Japanese patients.Patients with status epilepticus were selected from the database of the Emergency and Critical Care Center of Hitachi General Hospital. The subjects were patients whose status epilepticus was successfully stopped by diazepam, and in whom FPHT or LEV was administered after diazepam. As LEV injections recently became clinically available in Japan, the choice of drug was determined by the treatment period. Thus, 21 patients who were intravenously injected with LEV as a second-line therapy and 42 matched patients (historical controls) who were treated with FPHT (1:2) were selected.The subjects had a mean age of 64.0 ± 2.2 years, and included 48 males and 15 females. The status epilepticus control rates of the FPHT and LEV groups did not differ significantly (81.0% [34/42] vs 85.1% [18/21], respectively; P  =  .69). As for serious adverse events, a reduction in blood pressure was observed in the FPHT group, but not in the LEV group. The oral anticonvulsant switching rates of the 2 groups were similar, but the same-drug switching rates of the FPHT and LEV groups were 8.1% and 77.8%, respectively.The efficacy of intravenous LEV injections after status epilepticus was equivalent to that of FPHT, and the incidence of adverse events was lower in the LEV group. LEV is effective and safe at preventing recurrent seizures after status epilepticus following benzodiazepine treatment.

Carbamazepine versus phenytoin monotherapy for epilepsy: an individual participant data review

BACKGROUND

This is an updated version of the original Cochrane Review published in Issue 2, 2002 and its subsequent updates in 2010 and 2015.Epilepsy is a common neurological condition in which recurrent, unprovoked seizures are caused by abnormal electrical discharges from the brain. It is believed that with effective drug treatment, up to 70% of individuals with active epilepsy have the potential to become seizure-free and go into long-term remission shortly after starting drug therapy with a single antiepileptic drug in monotherapy.Worldwide, carbamazepine and phenytoin are commonly-used broad spectrum antiepileptic drugs, suitable for most epileptic seizure types. Carbamazepine is a current first-line treatment for partial onset seizures in the USA and Europe. Phenytoin is no longer considered a first-line treatment due to concerns over adverse events associated with its use, but the drug is still commonly used in low- to middle-income countries because of its low cost. No consistent differences in efficacy have been found between carbamazepine and phenytoin in individual trials, although the confidence intervals generated by these studies are wide. Differences in efficacy may therefore be shown by synthesising the data of the individual trials.

OBJECTIVES

To review the time to withdrawal, six- and 12-month remission, and first seizure with carbamazepine compared to phenytoin, used as monotherapy in people with partial onset seizures (simple partial, complex partial, or secondarily generalised tonic-clonic seizures), or generalised tonic-clonic seizures, with or without other generalised seizure types.

SEARCH METHODS

For the latest update we searched the Cochrane Epilepsy Group's Specialised Register (1st November 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 1st November 2016), MEDLINE (Ovid, 1946 to 1 November 2016), ClinicalTrials.gov (1 November 2016), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP, 1st November 2016). Previously we also searched SCOPUS (1823 to 16th September 2014) as an alternative to Embase, but this is no longer necessary, because randomised and quasi-randomised controlled trials in Embase are now included in CENTRAL. We handsearched relevant journals, contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in children or adults with partial onset seizures or generalised onset tonic-clonic seizures, comparing carbamazepine monotherapy versus phenytoin monotherapy.

DATA COLLECTION AND ANALYSIS

This is an individual participant data (IPD) review. Our primary outcome was time to withdrawal of allocated treatment, and our secondary outcomes were time to six-month remission, time to 12-month remission, and time to first seizure post-randomisation. We used Cox proportional hazards regression models to obtain study-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs) and the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

IPD were available for 595 participants out of 1192 eligible individuals, from four out of 12 trials (i.e. 50% of the potential data). For remission outcomes, HR greater than 1 indicates an advantage for phenytoin; and for first seizure and withdrawal outcomes, HR greater than 1 indicates an advantage for carbamazepine. The methodological quality of the four studies providing IPD was generally good and we rated it at low risk of bias overall in the analyses.The main overall results (pooled HR adjusted for seizure type) were time to withdrawal of allocated treatment: 1.04 (95% CI 0.78 to 1.39; three trials, 546 participants); time to 12-month remission: 1.01 (95% CI 0.78 to 1.31; three trials, 551 participants); time to six-month remission: 1.11 (95% CI 0.89 to 1.37; three trials, 551 participants); and time to first seizure: 0.85 (95% CI 0.70 to 1.04; four trials, 582 participants). The results suggest no overall statistically significant difference between the drugs for these outcomes. There is some evidence of an advantage for phenytoin for individuals with generalised onset seizures for our primary outcome (time to withdrawal of allocated treatment): pooled HR 0.42 (95% CI 0.18 to 0.96; two trials, 118 participants); and a statistical interaction between treatment effect and epilepsy type (partial versus generalised) for this outcome (P = 0.02). However, misclassification of seizure type for up to 48 individuals (32% of those with generalised epilepsy) may have confounded the results of this review. Despite concerns over side effects leading to the withdrawal of phenytoin as a first-line treatment in the USA and Europe, we found no evidence that phenytoin is more likely to be associated with serious side effects than carbamazepine; 26 individuals withdrew from 290 randomised (9%) to carbamazepine due to adverse effects, compared to 12 out of 299 (4%) randomised to phenytoin from four studies conducted in the USA and Europe (risk ratio (RR) 1.42, 95% CI 1.13 to 1.80, P = 0.014). We rated the quality of the evidence as low to moderate according to GRADE criteria, due to imprecision and potential misclassification of seizure type.

AUTHORS' CONCLUSIONS

We have not found evidence for a statistically significant difference between carbamazepine and phenytoin for the efficacy outcomes examined in this review, but CIs are wide and we cannot exclude the possibility of important differences. There is no evidence in this review that phenytoin is more strongly associated with serious adverse events than carbamazepine. There is some evidence that people with generalised seizures may be less likely to withdraw early from phenytoin than from carbamazepine, but misclassification of seizure type may have impacted upon our results. We recommend caution when interpreting the results of this review, and do not recommend that our results alone should be used in choosing between carbamazepine and phenytoin. We recommend that future trials should be designed to the highest quality possible, with considerations of allocation concealment and masking, choice of population, choice of outcomes and analysis, and presentation of results.

Connective Tissue Metabolism and Gingival Overgrowth

Gingival overgrowth occurs mainly as a result of certain anti-seizure, immunosuppressive, or antihypertensive drug therapies. Excess gingival tissues impede oral function and are disfiguring. Effective oral hygiene is compromised in the presence of gingival overgrowth, and it is now recognized that this may have negative implications for the systemic health of affected patients. Recent studies indicate that cytokine balances are abnormal in drug-induced forms of gingival overgrowth. Data supporting molecular and cellular characteristics that distinguish different forms of gingival overgrowth are summarized, and aspects of gingival fibroblast extracellular matrix metabolism that are unique to gingival tissues and cells are reviewed. Abnormal cytokine balances derived principally from lymphocytes and macrophages, and unique aspects of gingival extracellular matrix metabolism, are elements of a working model presented to facilitate our gaining a better understanding of mechanisms and of the tissue specificity of gingival overgrowth.

Lacking the 'protective label' of diabetes: Phenytoin-induced distal symmetrical peripheral neuropathy. A clinical case report

This report documents an unusual case of distal symmetrical peripheral neuropathy (DSPN) in an otherwise healthy patient without diabetes mellitus (DM) presenting to a podiatric wound care clinic. The development of gas gangrene coupled with Charcot neuroarthropathic changes ultimately resulted in a potentially life-saving transmetatarsal (TMT) amputation. Causation of, or at least a contributor to, the DSPN was likely phenytoin usage for epileptic seizures. Long-term use of phenytoin can lead to axonal shrinkage and random clusters of nerve demyelination [1]. Clinical standards for DM-induced DSPN indicate that annual comprehensive neurological assessment to detect nerve function deterioration is warranted [2]. This can aid in identifying patients at high risk of diabetic foot ulceration. However, oftentimes, patients exhibiting medication-induced neuropathy are not assessed to determine severity of the neuropathy nor are they educated about ulcer prevention in the same manner as patients with DM. This report advocates for a standardized threshold of diagnostic and preventative investigation for neuropathy of all aetiologies; diabetic, traumatic, viral, medication-induced and idiopathic.

Antiepileptic Drugs

PURPOSE OF REVIEW

Treatment of epilepsy starts with antiepileptic drug (AED) monotherapy. Knowledge of the spectrum of efficacy, clinical pharmacology, and modes of use for individual AEDs is essential for optimal treatment for epilepsy. This article addresses AEDs individually, focusing on key pharmacokinetic characteristics, indications, and modes of use.

RECENT FINDINGS

Older-generation AEDs are effective but have tolerability and pharmacokinetic disadvantages. Several newer-generation AEDs have undergone comparative trials demonstrating efficacy equal to and tolerability at least equal to or better than older AEDs as first-line therapy. The list includes lamotrigine, oxcarbazepine, levetiracetam, topiramate, and, more recently, zonisamide. Pregabalin was found to be less effective than lamotrigine. Lacosamide, pregabalin, and eslicarbazepine have undergone successful trials of conversion to monotherapy. Other newer-generation AEDs with a variety of mechanisms of action are suitable for adjunctive therapy. Rational AED combinations should avoid AEDs with unfavorable pharmacokinetic interactions or pharmacodynamic interactions related to mechanism of action.

SUMMARY

Knowledge of AED pharmacokinetics, efficacy, and tolerability profiles facilitates the choice of appropriate AED therapy for patients with epilepsy.

Purple glove syndrome following intravenous phenytoin administration

Purple glove syndrome (PGS) is a rare complication of intravenous phenytoin use that typically presents with pain, edema, and discoloration at the injection site that spreads to the distal limb. Several risk factors have been associated with the development of PGS; however, the etiology remains unknown. We present a case of PGS and briefly review the current understanding of this syndrome.

Phenytoin hypersensitivity syndrome masquerading as fever and systemic illness of unknown origin in an HIV-infected patient

A 32-year-old HIV-infected woman developed fever and systemic illness of unknown origin after being placed on phenytoin for seizures. Her clinical syndrome, skin biopsy findings, and clinical response to steroids were consistent with phenytoin hypersensitivity syndrome.

A well known and important adverse effect of phenytoin in a neurosurgical patient

Gum hypertrophy is a well-known and important adverse effect of phenytoin therapy in a neurosurgical patient. We present an interesting case of a 21-year-old man who, following head injury after a road traffic accident, developed status epilepticus diagnosed with gum hypertrophy in the jaws, with ongoing antiepileptics. He was managed conservatively as per hospital protocol.

Neurological manifestation of phenytoin toxicity, resulting from drug interaction with chloramphenicol: a case report

Phenytoin toxicity masquerading as deterioration of neurological symptoms caused by interaction with chloramphenicol is a very rare but real risk. To the authors’ knowledge only one such case occurring in humans has been reported in the English literature. No case of clinical phenytoin toxicity occurring at less than double the serum phenytoin therapeutic levels, occurring as a result of chlorampenicol interaction has been documented, hence our report. A 17 year old man, whose frontal subdural empyema had been drained, had his seizures well controlled on phenytoin. Shortly after, he had a parasagital subdural empyema which was also drained. He was put on chloramphenicol. He improved tremendously until he then developed cerebellar symptoms. Phenytoin levels were noted to be almost twice the maximum therapeutic value. On stopping chloramphenicol, phenytoin levels normalized and symptoms resolved. Possibility of phenytoin toxicity should always be entertained in patients who are also taking chlorampenicol, presenting with new or worsening neurological symptoms.

DRESS Syndrome Presents as Leukoencephalopathy

DRESS syndrome (Drug Rash with Eosinophilia and Systemic Symptoms) is a potentially life-threatening syndrome, which reflects a serious hypersensitivity reaction to drugs, presenting by generalized skin rash, fever, eosinophilia, atypical lymphocytosis, and internal organ involvement. Herein a 21-month old male infant with DRESS and Encephalopathy syndrome is presented who complicated after phenobarbital usage that persisted due to phenytoin cream usage. The case received phenobarbital after a seizure disorder presented as "status epilepticus". He developed drug eruption, fever, hepatosplenomegaly, increased liver enzymes, encephalopathy and progressive loss of consciousness with extensive hyperintense white matter lesions in brain MRI. After discontinuation of phenobarbital and phenytoin, all symptoms were resolved, while brain MRI became normal after two months. To our best knowledge, this is the first reported case that developed leukoencephalopathy along with DRESS syndrome.

Carbamazepine versus phenytoin monotherapy for epilepsy: an individual participant data review

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 2, 2002 and its subsequent update in 2010.Epilepsy is a common neurological condition in which recurrent, unprovoked seizures are caused by abnormal electrical discharges from the brain. It is believed that with effective drug treatment, up to 70% of individuals with active epilepsy have the potential to become seizure-free and go into long-term remission shortly after starting drug therapy with a single antiepileptic drug in monotherapy.Worldwide, carbamazepine and phenytoin are commonly used broad spectrum antiepileptic drugs, suitable for most epileptic seizure types. Carbamazepine is a current first line treatment for partial onset seizures in the USA and Europe. Phenytoin is no longer considered a first line treatment due to concerns over adverse events associated with its use, however the drug is still commonly used in low- to middle-income countries due to it's low cost. No consistent differences in efficacy have been found between carbamazepine and phenytoin in individual trials, however the confidence intervals generated by these studies are wide. Therefore, differences in efficacy may be shown by synthesising the data of the individual trials.

OBJECTIVES

To review the time to withdrawal, six- and 12-month remission, and first seizure of carbamazepine compared to phenytoin when used as monotherapy in people with partial onset seizures (simple partial, complex partial, or secondarily generalised tonic-clonic seizures) or generalised tonic-clonic seizures, with or without other generalised seizure types.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialised Register (16 September 2014), the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 8), MEDLINE (1946 to 16 September 2014), SCOPUS (1823 to 16 September 2014), ClinicalTrials.gov (16 September 2014), and the World Health Organization (WHO) International Clinical Trials Registry Platform ICTRP (18 September 2014). We handsearched relevant journals, contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in children or adults with partial onset seizures or generalised onset tonic-clonic seizures with a comparison of carbamazepine monotherapy versus phenytoin monotherapy.

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD) review. Our primary outcome was time to withdrawal of allocated treatment, and our secondary outcomes were time to 12-month remission, time to six-month remission and time to first seizure post-randomisation. We used Cox proportional hazards regression models to obtain study-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs) and the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

IPD were available for 595 participants out of 1192 eligible individuals, from four out of 12 trials (i.e. 50% of the potential data). For remission outcomes, HR > 1 indicates an advantage for phenytoin; and for first seizure and withdrawal outcomes, HR > 1 indicates an advantage for carbamazepine. Methodological quality of the four studies providing IPD was generally good and we rated it at low risk of bias overall in the analyses.The main overall results (pooled HR adjusted for seizure type) were time to withdrawal of allocated treatment: 1.04 (95% CI 0.78 to 1.39); time to 12-month remission: 1.01 (95% CI 0.78 to 1.31); time to six-month remission: 1.11 (95% CI 0.81 to 1.37); and time to first seizure: 0.85 (95% CI 0.70 to 1.04). The results suggest no overall statistically significant difference between the drugs for these outcomes. There is some evidence of an advantage for phenytoin for individuals with generalised onset seizures for our primary outcome (time to withdrawal of allocated treatment): pooled HR 0.42 (95% CI 0.18 to 0.96); and a statistical interaction between treatment effect and epilepsy type (partial versus generalised) for this outcome (P = 0.02), however misclassification of seizure type for up to 48 individuals (32% of those with generalised epilepsy) may have confounded the results of this review. Despite concerns over side effects leading to the withdrawal of phenytoin as first line treatment in the USA and Europe, we found no evidence that phenytoin is more likely to be associated with serious side effects than carbamazepine; 26 individuals withdrew from 290 randomised (9%) to carbamazepine due to adverse effects compared to 12 out of 299 (4%) randomised to phenytoin from four studies conducted in the USA and Europe (risk ratio (RR) 1.42, 95% CI 1.13 to 1.80, P = 0.014). We rated the quality of the evidence as low - moderate according to GRADE criteria, due to imprecision and potential misclassification of seizure type.

AUTHORS' CONCLUSIONS

We have not found evidence that a statistically significant difference exists between carbamazepine and phenytoin for the efficacy outcomes examined in this review, however, CIs are wide and the possibility of important differences existing has not been excluded. There is no evidence in this review that phenytoin is more strongly associated with serious adverse events than carbamazepine. There is some evidence that participants with generalised seizures may be less likely to withdraw early from phenytoin than carbamazepine, but misclassification of seizure type may have impacted upon the results of this review. We recommend caution when interpreting the results of this review, and do not recommend that the results of this review alone should be used in choosing between carbamazepine and phenytoin. We recommend that future trials should be designed to the highest quality possible with considerations on allocation concealment and masking, choice of population, choice of outcomes and analysis, and presentation of results.

Effect observation of anti epileptic drugs on serum folic acid and vitamin B12 of epileptic patients

AIM

Comparative analysis of the effect of antiepileptic drugs on the epileptic (tonic clonic seizure type) patient's serum folate and vitamin B12 concentrations.

METHODS

Consecutively, 84 cases from September 2010 to September 2014 from the Department of Internal Medicine of our hospital were considered to diagnose as epilepsy nerve. Among which, 49 cases received anti epileptic drug treatment (treatment group), 35 cases received treatment without anti epileptic drugs (non-treatment group); At the same period, 42 nonepileptic patients (control group) underwent the analysis of the difference of serum folate and vitamin B12 concentrations of among the three groups of patients before the test, and at the end of test with the contrast analysis of difference of clinical efficiency and thrombosis rate.

RESULTS

Serum folic acid level of patients in the treatment group decreased significantly after test, vitamin B12 level was significantly higher, the differences were statistically significant (P<0.05), but folic acid and vitamin B12 concentration of non-treatment group and the control group did not change, and the differences were not statistically significant (P>0.05). Clinical efficiency of treatment group patients was significantly higher than that of the non-treatment group; the incidence of thrombosis was significantly lower than that of the non-treatment group, and the difference was statistically significant (P<0.05).

CONCLUSION

Antiepileptic drugs can significantly improve clinical efficacy of the epilepsy tonic clonic seizure type patients, which may be related to the decrease of serum levels of folate and vitamin B12-increased concentration.