Intravenous administration of fosphenytoin: options for the management of seizures

A critical review of fosphenytoin sodium injection for the treatment of status epilepticus in adults and children

INTRODUCTION

Status epilepticus (SE) is a neurological emergency that can occur in patients with or without epilepsy. Rapid treatment is paramount to mitigate risks of neuronal injury, morbidity/mortality, and healthcare-cost burdens associated with SE. Fosphenytoin is the prodrug of phenytoin designed to enable faster administration and improved tolerability as compared to intravenous (IV) phenytoin in the treatment of SE.

AREAS COVERED

This review evaluates the chemistry, pharmacokinetics, pharmacodynamics, safety, and tolerability of fosphenytoin. Efficacy data for fosphenytoin in the treatment of SE in adults and children are analyzed from initial phase I trials in 1988 through current phase III trials, including the Established Status Epilepticus Treatment Trial (ESETT).

EXPERT OPINION

IV phenytoin is an established treatment of SE, but its alkaline aqueous vehicle is associated with dermatologic irritation and systemic complications when rapidly infused. The water-soluble nature of its prodrug, fosphenytoin, allows for rapid infusion, and it is rapidly converted to phenytoin when administered intravenously or intramuscularly. In the ESETT, IV fosphenytoin demonstrated similar efficacy in treatment of established SE when compared to IV levetiracetam and IV valproate in adults and children, making it a reasonable choice in the treatment of SE that is unresponsive to benzodiazepines.

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.

Antiepileptic Drug Therapy for Status Epilepticus

Status epilepticus (SE) is one of the most serious neurologic emergencies. SE is a condition that encompasses a broad range of semiologic subtypes and heterogeneous etiologies. The treatment of SE primarily involves the management of the underlying etiology and the use of antiepileptic drug therapy to rapidly terminate seizure activities. The Drug Committee of the Korean Epilepsy Society performed a review of existing guidelines and literature with the aim of providing practical recommendations for antiepileptic drug therapy. This article is one of a series of review articles by the Drug Committee and it summarizes staged antiepileptic drug therapy for SE. While evidence of good quality supports the use of benzodiazepines as the first-line treatment of SE, such evidence informing the administration of second- or third-line treatments is lacking; hence, the recommendations presented herein concerning the treatment of established and refractory SE are based on case series and expert opinions. The choice of antiepileptic drugs in each stage should consider the characteristics and circumstances of each patient, as well as their estimated benefit and risk to them. In tandem with the antiepileptic drug therapy, careful searching for and treatment of the underlying etiology are required.

Phenytoin versus fosphenytoin for second-line treatment of status epilepticus: propensity score matching analysis using a nationwide inpatient database

PURPOSE

For status epilepticus, the choice of antiepileptic drugs for second-line treatment after benzodiazepine remains controversial: phenytoin or fosphenytoin are recommended, however, it has been unknown which is better. Using a nationwide database, we compared the efficacy and safety of them.

METHOD

An observational study conducted with the Japanese Diagnosis Procedure Combination inpatient database identified adult patients who had been admitted for status epilepticus and who had received intravenous diazepam on the day of admission from January 1, 2011 through December 31, 2015. Propensity score matching was applied to compare outcomes of the phenytoin and fosphenytoin groups.

RESULTS

The analysis examined data of 5265 patients: 2969 patients received phenytoin; 2296 received fosphenytoin, on the day of admission. One-to-one propensity score matching created 1871 matched pairs. No significant difference was found for vasopressor use on the day of admission (4.2 % vs. 4.4 %; odds ratio 1.07; 95 % confidence intervals 0.77-1.48; p = 0.69), or for mechanical ventilation on the day of admission, in-hospital mortality, length of hospital stay, or total hospitalization cost. Higher age, comorbidity of cardiac diseases and lower body mass index were associated significantly with increased vasopressor use, whereas the dose of phenytoin equivalents and the choice of fosphenytoin were not.

CONCLUSIONS

This nationwide observational study found no evidence that fosphenytoin provides higher efficacy or safety than phenytoin for treatment of status epilepticus in adults after diazepam. Age, cardiac disease and low body mass index were identified as independent risk factors for vasopressor use in both phenytoin and fosphenytoin.

IV fosphenytoin in obese patients: Dosing strategies, safety, and efficacy

Background

Previous studies evaluated the disposition of IV phenytoin loading doses and found that obese patients had increased drug distribution into excess body weight, larger volumes of distribution, and longer half-lives when compared to their nonobese counterparts. We assess the safety and efficacy of fosphenytoin loading doses in patients with different body mass indices (BMIs).

Methods

A retrospective chart review was conducted in 410 patients who received fosphenytoin. Patients were divided into 2 groups: BMI <30 (nonobese) and BMI ≥30 (obese). Patient demographics, fosphenytoin dose administered in mg/kg body weight, renal and liver function tests, fosphenytoin drug levels, and pre- and post-fosphenytoin administration vital signs were collected to assess for adverse events. Necessity of additional antiepileptic loading doses was used as a surrogate for clinical efficacy.

Results

The median dose of fosphenytoin administered was 19 mg/kg (interquartile range 15-20). The most frequently encountered adverse event was hypotension, which occurred in 39% of the cohort. Using a Bonferroni adjustment for multiple comparisons, there were no differences in adverse events between the 2 groups. The need for additional antiepileptic loading doses was not different between the 2 groups (p = 0.07).

Conclusions

The incidence of adverse events and the need for repeat loading antiepileptic medications was similar between the 2 groups. From our findings, the patients in our study did not receive empiric loading dose adjustments and the current method of loading fosphenytoin achieves similar outcomes, regardless of the patient's BMI.

Epilepsy in the elderly

Epilepsy is the most common serious neurological disorder in the elderly after stroke and dementia. It may be more important for elderly people because it is intermittent and unpredictable. There is no reliable diagnostic test and so its diagnosis and management requires clinical acumen and experience. The situation is further complicated because the elderly may have many comorbidities and therefore may have many other reasons for losing consciousness. Despite their growing number, there is remarkably little research to underpin the best epilepsy management in the elderly. This article summarizes the scope of epilepsy in elderly people, highlights cerebrovascular and neurodegenerative diseases as the main underlying etiologies, explores the diagnostic challenges in this age group, including the hurdles and processes in their investigation, and examines pertinent clinical management issues.

Evaluation of intramuscular fosphenytoin vs intravenous phenytoin loading in the ED

OBJECTIVE

A comparison of length of stay in an emergency department (ED) after loading patients at risk for seizures with either intravenous (IV) phenytoin or intramuscular (IM) fosphenytoin was studied.

METHODS

This was a retrospective observational cohort study that was conducted over a 24-month period in an academic teaching hospital (693 beds). Patients included were 18 years or older, discharged from the ED without hospital admission, and loaded with either IV phenytoin or IM fosphenytoin. The primary end point was the comparison of length of stay in the ED until discharge after loading. Characterization of seizure etiology, cardiac risk factors, and adverse drug events were also observed.

RESULTS

A total of 51 patients were evaluated who received IV phenytoin compared with 59 for IM fosphenytoin. The median time-to-discharge difference between IV phenytoin vs IM fosphenytoin was 1:49 hours (95% confidence interval, 1:24-2:24 hours; P < .001). There was no statistical difference in cardiac risk factors and occurrence of adverse drug events between groups.

CONCLUSIONS

This study found that patients were discharged from the ED earlier with the loading of IM fosphenytoin compared to IV phenytoin.

Blood pressure changes after intravenous fosphenytoin and levetiracetam in patients with acute cerebral symptoms

PURPOSE

To study the incidence and extent of the occasionally noted hypotension after intravenous (IV) infusions of fosphenytoin (FOS) and levetiracetam (LEV) in patients presenting with acute cerebral symptoms.

METHODS

Retrospective data collection of consecutive patients with acute cerebral symptoms who received IV infusions of a single dose of 750 mg or more of either fosphenytoin or levetiracetam and had documented blood pressure values in the 2h prior and the 2h after their IV infusion.

RESULTS

More than 10 mmHg drop in the systolic, diastolic and MBP was observed in the FOS group following the IV infusion (-16.82 mmHg, -11.60 mmHg, and 13.34 mmHg, respectively). However, there was not a significant change in the MBP after LEV infusion (1.54 mmHg, 1.84 mmHg, and 1.74 mmHg for systolic, diastolic and MBP change, respectively). The difference in the systolic, diastolic and MBP changes between the two groups was statistical significant (all p values are <0.0001) after adjusting for age, clinical presentations of the patients and if they were on any antihypertensive medication in the hospital. Sixty two percent of patients who received FOS had >10 mmHg decrease in their MBP. In the LEV group, only 2 of the 50 patients (4%) had >10 mmHg decrease in their MBP. The difference in proportion of the patients with >10 mmHg drop in MBP between the two study groups is also statistically significant (p<0.001) for age, clinical presentations of the patients and if they were on any antihypertensive medication in the hospital.

CONCLUSIONS

IV infusion of FOS in subjects presenting with acute cerebral symptoms may cause significant decreases in their blood pressure. This was not seen in patients receiving IV LEV infusions. Since maintaining adequate cerebral perfusion pressure is a key point in the management of patients with acute cerebral symptoms, the results of this study may carry a clinical impact on the management of this subgroup of patients.

Comparative Efficacy and Safety of Antiepileptic Drugs for the Treatment of Status Epilepticus

Status epilepticus (SE) is a medical emergency with high mortality rate. Common causes of SE include noncompliance with antiepileptic medications, drug- and alcohol-related etiologies, and central nervous system (CNS) infections. Because prolonged seizures can cause neuronal damage, treatment should be initiated promptly to avoid potential complications. Previous studies support intravenous (IV) lorazepam as first-line therapy and IV phenytoin or fosphenytoin as a second-line medication. If first-and second-line medications fail to control SE, further treatment with propofol, pentobarbital, midazolam, or other medications should be considered. Many of the drugs currently used to control SE are associated with sedation, respiratory suppression, hypotension, cardiac dysrhythmia, and anaphylactic reactions. Therefore, IV valproate or other newer antiepileptic drugs may be considered as an alternative third-line therapy for those who cannot tolerate the hypotensive effects of other anticonvulsants. This paper reviews comparative effectiveness and safety concerns among frequently used medications for SE.

Levetiracetam is neuroprotective in murine models of closed head injury and subarachnoid hemorrhage

OBJECTIVES

Prophylactic treatment with antiepileptic drugs is common practice following subarachnoid hemorrhage (SAH) and traumatic brain injury. However, commonly used antiepileptic drugs have multiple drug interactions, require frequent monitoring of serum levels, and are associated with adverse effects that may prompt discontinuation. In the current study, we test the hypothesis that levetiracetam, an anticonvulsant with favorable interaction and adverse event profiles, is neuroprotective in clinically relevant models of SAH and closed head injury (CHI).

METHODS

A single intravenous dose of vehicle, low-dose (18 mg/kg), or high-dose (54 mg/kg) levetiracetam was administered intravenously followed CHI. Functional assessments were performed on a daily basis, and histological assessments performed at 24 hours. In a separate series of experiments, mice were randomized to receive intravenous administration of vehicle, low-dose, or high-dose levetiracetam every 12 hours for 3 days following SAH. Functional endpoints were assessed daily, followed by measurement of MCA luminal diameter on day 3.

RESULTS

A single dose of levetiracetam improved functional and histological outcomes after CHI. This effect appeared specific for levetiracetam and was not associated with fosphenytoin treatment. Treatment with levetiracetam also improved functional outcomes and reduced vasospasm following SAH.

CONCLUSION

Levetiracetam is neuroprotective in clinically relevant animal models of SAH and CHI. Levetiracetam may be a therapeutic alternative to phenytoin following acute brain injury in the clinical setting when seizure prophylaxis is indicated.

Fosphenytoin may cause hemodynamically unstable bradydysrhythmias

The prodrug fosphenytoin (FOS) was recently introduced as an alternative to phenytoin (PTN) and has since become a first line therapy for status epilepticus. Unlike PTN, FOS generally has been considered to be safe from cardiac toxicity. To better characterize cardiac toxicity associated with FOS administration, we performed a review of the Food and Drug Administration's Adverse Event Reporting System databank for reports of possible FOS toxicity from 1997-2002. There were 29 applicable reports of adverse cardiac events likely related to FOS infusion, including 10 cardiac deaths. Among survivors, there were four cases of high-grade atrioventricular block, and five cases of transient sinus arrest. Our data suggest that FOS may produce more cardiac toxicity than previously thought. Clinicians should consider administering intravenous FOS in a monitored setting for selected high-risk patients.

Animal models for the development of new neuropharmacological therapeutics in the status epilepticus

Status epilepticus (SE) is a major medical emergency associated with significant morbidity and mortality. SE is best defined as a continuous, generalized, convulsive seizure lasting > 5 min, or two or more seizures during which the patient does not return to baseline consciousness. The relative efficacy and safety of different drugs in the treatment of human SE should be determined in a prospective, randomized, blinded study. However, complementary animal models of SE are required to answer important questions concerning the treatment of SE because of the obvious difficulties of setting up such studies in clinical emergency conditions. This review offers an overview of the implementation and characteristics of some of the most prevalent animal models of SE currently in use. A description is also provide about how animal models of SE may facilitate the use of neurobiological techniques to successfully address critical questions in the drug treatment of SE. In particular, the experience with recently introduced drugs such as intravenous valproate will be addressed. Finally, the importance of some animal models and pharmacological approaches is explained and we discuss their impact in the development of therapeutic strategies to improve pharmacological treatment for SE is discussed.

A comparison of phenytoin-loading techniques in the emergency department

OBJECTIVES

To compare the effectivenesses of three phenytoin-loading techniques.

METHODS

Patients with subtherapeutic phenytoin concentrations who presented within 48 hours of a seizure were randomized to receive either 20 mg/kg of oral phenytoin (PO), divided in maximum doses of 400 mg every two hours, 18 mg/kg of intravenous phenytoin (IVP) at an initial infusion rate of 50 mg/min, or 18 mg/kg (phenytoin equivalents) of intravenous fosphenytoin (IVF) at an initial infusion rate of 150 mg/min.

RESULTS

A total of 45 patients were enrolled: 16 in the PO group, 14 in the IVP group, and 15 in the IVF group. The times required to reach therapeutic drug concentrations were (mean +/- standard deviation [SD]) 5.62 +/- 0.28 hours, 0.24 +/- 0.3 hours, and 0.21 +/- 0.28 hours, respectively. A total of 17, 27, and 32 adverse drug events were observed in the PO, IVP, and IVF groups, respectively, with significantly fewer events in the PO group (p = 0.02, p = 0.01). No significant difference was found between the numbers of necessary adjustments to the infusions in the two IV groups. The average time to safe emergency department discharge was significantly shorter for the IV groups compared with the PO group (p < 0.001).

CONCLUSIONS

Oral loading has fewer adverse drug events than either IV loading method, but its use may be limited when therapeutic concentrations are required quickly. Although IVF loading is faster, from an adverse-drug event perspective, no advantage of IVF over IVP was apparent.

Treating epilepsy in the elderly: safety considerations

The incidence of epilepsy increases with advancing age. Epilepsy in the elderly has different aetiologies from that in younger populations, cerebrovascular disease being the most common condition associated with seizures. Partial seizures are the predominant seizure type in older patients. A diagnosis of epilepsy in the elderly is based mainly on the history and is frequently delayed. In addition, seizure imitators are especially frequent. In many cases ancillary tests for diagnosis may show normal age-related variants, sometimes making results difficult to interpret. Treating epilepsy in the elderly is problematic due to a number of issues that relate to age and comorbidity. The physical changes associated with increasing age frequently lead to changes in the pharmacokinetics of many anticonvulsants. The treatment of epilepsy in the elderly is also complicated by the existence of other diseases that might affect the metabolism or excretion of anticonvulsants and the presence of concomitant medications that might interact with them. Moreover, specific trials of anticonvulsants in the aged population are scarce. General guidelines for treatment include starting at lower doses, slowing the titration schedule, individualising the choice of anticonvulsant to the characteristics of the patient, avoiding anticonvulsants with important cognitive or sedative adverse effects, and where possible, treating with monotherapy.

A prospective study of the incidence of the purple glove syndrome

PURPOSE

Phenytoin (PHT) has been widely used intravenously for the treatment of seizures since 1956, and for many years, it has been considered first-line therapy for status epilepticus. It is routinely administered intravenously in emergency departments and hospitals for patients who have had isolated seizures and for many patients undergoing neurosurgical procedures who are unable to receive oral medication. Adverse reactions from PHT have been widely studied for years, but in the past decade, new adverse reactions have been identified. One of these adverse reactions is the purple glove syndrome (PGS), characterized by edema, discoloration, and pain distal to the site of i.v. administration of PHT. Because there have been no prospective reports of the incidence of PGS, the objective of the study was to report the incidence of this syndrome.

METHODS

We enrolled 179 consecutive exposures to i.v. PHT at Henry Ford Hospital. Distal portions of the upper extremities were examined and digitally photographed by one of the authors (J.G.B.). The photos were blindly evaluated by the third author (G.L.B.) for PGS. Demographic and pertinent medical history was recorded for all patients, and outcome for those who experienced PGS was recorded. Associations between PGS, demographic, and medical history information were assessed.

RESULTS

In only three of the 179 exposures did PGS develop. In both patients, the severity of the clinical picture was mild and did not required prolonged hospitalization or specialized treatment.

CONCLUSIONS

PGS is an infrequent and mild adverse effect of i.v. PHT administration.

Fosphenytoin: an intravenous option for the management of acute trigeminal neuralgia crisis

Timely management of trigeminal neuralgia presenting with severe, sustained, crescendo pain can be difficult with oral medications. More rapid pain control often can be achieved using intravenous phenytoin. Fosphenytoin is a phosphate ester prodrug of phenytoin that is significantly better tolerated parenterally than phenytoin in the treatment of epilepsy. Three patients with trigeminal neuralgia refractory to oral medications and presenting with crisis pain were treated urgently with intravenous fosphenytoin. In each case complete relief of pain was achieved for a duration of two days, affording a window of opportunity to modify oral pharmacotherapeutic strategies or to control pain in preparation for invasive neurosurgical intervention.

Phenytoin and fosphenytoin: a model of cost and clinical outcomes

We developed a pharmacoeconomic model to compare costs and clinical outcomes of administering phenytoin and fosphenytoin alone and in combination in hospitalized patients. Effectiveness data were obtained by distributing a questionnaire to 33 registered nurses at three acute care hospitals who worked in critical care, neurology services, or emergency department. The questionnaire addressed methods of phenytoin and fosphenytoin administration, frequency of adverse reactions, methods of treating adverse reactions, and demographic information. The model estimated that if 50% of phenytoin loading doses were substituted with fosphenytoin, a reduction in adverse events resulted in an estimated increase of $36/patient cost to the hospital. If phenytoin maintenance dosages were substituted with fosphenytoin, the model predicted essentially no change in cost to the hospital. It appears that fosphenytoin reduces adverse events at a reasonable increase in total hospital costs.

Phenytoin penetration into brain after administration of phenytoin or fosphenytoin

PURPOSE

This study was designed to measure the brain penetration of phenytoin (PHT) after intravenous (i.v.) administration of either standard PHT or fosphenytoin (FPHT), a PHT prodrug. The study was formulated to answer the question whether the time required for FPHT to be converted to PHT in the bloodstream would delay the accumulation of PHT in brain.

METHODS

Four rats were sampled at various times after intravenous infusion of 30 mg/kg PHT i.v. or 30 mg/kg PHT equivalents of FPHT i.v. PHT was measured in serum, protein-free ultrafiltrate, and in brain, by using high-performance liquid chromatography.

RESULTS

Although the initial PHT-free fraction was significantly higher for FPHT-treated rats than it was for PHT-treated rats, brain PHT levels were significantly reduced after infusion of FPHT.

CONCLUSIONS

When FPHT is used for treatment of generalized status epilepticus, it should be anticipated that lower initial brain PHT levels will be achieved than are typically found with standard PHT.

Fosphenytoin in infants

In comparison with phenytoin preparations, which have a pH value of 11, fosphenytoin, a phosphorylated prodrug of phenytoin, has a pH value of only 8.6, which decreases the risk of cardiovascular and cutaneous side effects. The near-neutral pH value of fosphenytoin allows effective intravenous or intramuscular administration. A 1-mg phenytoin equivalent (PE) of fosphenytoin is converted to 1 mg of phenytoin in adults. We describe four infants whose seizures were treated with intravenous fosphenytoin. We had difficulty maintaining therapeutic serum phenytoin levels of 10 to 20 microg/mL on doses of 5 to 8 mgPE/kg/day, and many bolus doses of 5 to 10 mgPE/kg or maintenance doses of more than 10 mgPE/kg/day were given. Despite increased doses in three out of the four patients, a therapeutic serum phenytoin level was not maintained. From our experience, careful and individual dosing of fosphenytoin in this age group can be considered.

Incidence and clinical consequence of the purple glove syndrome in patients receiving intravenous phenytoin

OBJECTIVE

To determine the incidence, risk factors, and long-term sequelae of the purple glove syndrome (PGS) in hospital patients receiving IV phenytoin.

BACKGROUND

PGS is a poorly understood, potentially serious local complication of IV phenytoin administration characterized by progressive distal limb edema, discoloration, and pain.

METHODS

The pharmacologic records of the Mayo Foundation hospitals were reviewed to identify 179 consecutive patients who had IV phenytoin ordered during a 3-month period. Their hospital records were then reviewed to confirm IV phenytoin treatment, the frequency of PGS (defined as the progressive development of edema, discoloration, and pain in the limb after administration of IV phenytoin), and the outcome of PGS.

RESULTS

A total of 152 patients received IV phenytoin, and nine (5.9%) developed PGS. PGS patients received a greater median initial dose of phenytoin, total 24-hour dose, and total number of doses (all p < 0.05). In addition, the median age of the PGS patients was older, their infusion was more often given for acute seizures, it was less likely to be administered in the operating room, and the length of their hospital stay was longer (all p < 0.05). One patient required surgical therapy, and all other patients resolved within 3 weeks with conservative management.

CONCLUSIONS

PGS is not rare and elderly patients and individuals receiving large, multiple doses are particularly at risk. This iatrogenic complication may be preventable by substituting fosphenytoin for IV phenytoin.

Epilepsy in older adults: causes, consequences and treatment

OBJECTIVES

Seizures and epilepsy are common problems in older adults. Although, the highest incidence of seizures and epilepsy occurs in individuals more than 65 years of age, the magnitude of this public health problem, and its consequences on the quality of life of older adults, are not appreciated. Moreover, there is no consensus on the most appropriate way to diagnose or manage epilepsy in this population. This report reviews the current literature on all aspects of epilepsy in older people.

DESIGN/METHODS

The medical literature was reviewed for all articles pertaining to pathophysiology, diagnosis, and treatment of epilepsy in older people.

RESULTS

Epidemiology, etiology, diagnosis, use of diagnostic tests including EEG and imaging, new medical and surgical treatments, and psychosocial issues as they relate to older epilepsy patient are discussed. Several questions that merit future systematic investigation are presented.

CONCLUSION

Seizures and epilepsy in older people are much more common than is generally known. There are unique issues related to this population with regard to diagnosis and treatment. Several new medical and surgical therapies are now available for all epilepsy patients, some of which may be helpful for the older epilepsy patient.

Benefit of neurophysiologic monitoring for pediatric cardiac surgery

BACKGROUND

Pediatric patients undergoing repair of congenital cardiac abnormalities have a significant risk of an adverse neurologic event. Therefore this retrospective cohort study examined the potential benefit of interventions based on intraoperative neurophysiologic monitoring in decreasing both postoperative neurologic sequelae and length of hospital stay as a cost proxy.

METHODS

With informed parental consent approved by the institutional review board, electroencephalography, transcranial Doppler ultrasonic measurement of middle cerebral artery blood flow velocity, and transcranial near-infrared cerebral oximetry were monitored in 250 patients. An interventional algorithm was used to detect and correct specific deficiencies in cerebral perfusion or oxygenation or to increase cerebral tolerance to ischemia or hypoxia.

RESULTS

Noteworthy changes in brain perfusion or metabolism were observed in 176 of 250 (70%) patients. Intervention that altered patient management was initially deemed appropriate in 130 of 176 (74%) patients with neurophysiologic changes. Obvious neurologic sequelae (i.e., seizure, movement, vision or speech disorder) occurred in five of 74 (7%) patients without noteworthy change, seven of 130 (6%) patients with intervention, and 12 of 46 (26%) patients without intervention (p = 0.001). Survivors' median length of stay was 6 days in the no-change and intervention groups but 9 days in the no-intervention group. In addition, the percentage of patients in the no-intervention group discharged from the hospital within 1 week (32%) was significantly less than that in either the intervention (51%, p = 0.05) or no-change (58%, p = 0.01) groups. On the basis of an estimated hospital neurologic complication cost of $1500 per day, break-even analysis justified a hospital expenditure for neurophysiologic monitoring of $2142 per case.

CONCLUSIONS

Interventions based on neurophysiologic monitoring appear to decrease the incidence of postoperative neurologic sequelae and reduce the length of stay. Inasmuch as the break-even cost for neurophysiologic monitoring is more than four times the actual average charge, both patients and hospital may profit from this service. Because this study was not a truly randomized clinical trial, unintentional statistical bias may have occurred and caution is urged in interpreting the magnitude of apparent intergroup outcome differences.

New antiepileptic drugs. Overcoming the limitations of traditional therapy

Several new antiepileptic drugs have become available recently. Since seizures and epilepsy are common, primary care physicians are likely to encounter a patient who is taking one of these new medications. Successful medical management of epilepsy requires a proper understanding of medication half-life, indications, and side effects. Felbamate has a broad spectrum of efficacy but is limited by side effects and idiosyncratic reactions. Fosphenytoin has the efficacy of phenytoin and offers the advantage of intramuscular and intravenous dosing without the significant adverse effects associated with intravenous phenytoin; however, it is expensive. Gabapentin has minimal side effects and drug interactions yet has limited efficacy for seizures. Lamotrigine has broad seizure efficacy but requires a slow adjustment to therapeutic levels. Topiramate has minimal drug interactions, but therapy must be initiated slowly to avoid side effects. All of the new antiepileptics hold great promise in the management of patients with recurrent seizures.

New antiepileptic drugs in children: present and future

The pharmacologic management of epilepsy has progressed greatly during the last decade. New medications are available for the management of refractory patients, and more are being developed. For some patients, these productions offer added efficacy, better tolerability, and some pharmacodynamic advantages. Since preapproval studies include few pediatric trials, the final role of these medications in the treatment of childhood epilepsy will be dictated by additional studies and postmarketing experience.

Trigeminal neuralgia : a guide to drug choice

Trigeminal neuralgia, also known as tic douloureux, is an idiopathic condition of severe, unilateral, paroxysmal facial pain. The abrupt nature of the painful attacks (a temporal profile that is similar to that of seizures) led to the discovery that some anticonvulsant drugs are effective against neuralgia.Carbamazepine is the drug of choice, and treatment requires careful dosage titration. Baclofen, phenytoin and sodium valproate are also effective. Transient relief is sometimes possible with local anaesthetics. Limited data suggest that topical capsaicin, and tizanidine, lamotrigine, oxcarbazepine, pyridostigmine and enalapril have helped some patients. While effective, other drugs are limited by their adverse effects; for example, clonazepam is too sedating, pimozide induces extrapyramidal adverse effects, and tocainide and felbamate can cause aplastic anaemia. Phenobarbital (phenobarbitone), opioids, mexiletine, tricyclic antidepressants, corticosteroids, nonsteroidal anti-inflammatory drugs and sympatholytics are ineffective.The antineuralgic effect of any drug may eventually wear off. If this occurs, combination therapy can restore pain relief, as can the reintroduction of a previously effective drug following a drug-free interval.Similar pharmacological strategies potentially apply to other paroxysmal pain syndromes such as vagoglossopharyngeal neuralgia. Clinical overlap with multiple sclerosis or cluster headache suggests additional drugs that may be useful in specific patients. Effective neurosurgical procedures exist for patients with trigeminal neuralgia that is refractory to medications.

A pharmacoeconomic evaluation of intravenous fosphenytoin (Cerebyx) versus intravenous phenytoin (Dilantin) in hospital emergency departments

The cost of emergency department services has become a major concern for patients, providers, and payers. Solid economic information is needed to provide a rationale for the selection of therapeutic options and the provision of care that is both clinically and financially prudent. To assess the full cost of care for patients with seizures who are treated in an acute care setting, a modified activity-based cost-accounting model was developed. The model was populated with data from a double-masked, parallel-group, single-dose, multicenter clinical trial designed to investigate the safety and tolerability of phenytoin (Dilantin) and fosphenytoin (Cerebyx) given intravenously in equivalent loading doses according to established recommendations. A total of 52 patients were enrolled in the trial; 13 were given phenytoin and 39 were given fosphenytoin. Salaries and benefits of emergency medical services personnel, drug acquisition costs, and direct and indirect overhead expenditures common to a large hospital emergency department comprised the total costs to treat enrolled patients and manage adverse events. The average cost to treat patients with fosphenytoin was lower than the cost to treat similar patients with phenytoin based on the frequency of adverse events associated with each comparator and the resources (human and material) consumed in the management of those events.