Lamotrigine-associated anticonvulsant hypersensitivity syndrome

Lamotrigine induced toxic epidermal necrolysis: A case report

Introduction

A wide spectrum of cutaneous adverse reactions ranging from simple maculopapular rashes to more severe and life-threatening reactions like Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis(TEN) have been described after exposure to many antiepileptic drugs. Although the adverse effect following lamotrigine has been reported after a low initial dosage, the risk of developing TEN is relatively rare.

Case report

We present a 23-year-old female, 6 months post-partum, a case of complex partial seizure, who developed TEN after 14 days of monotherapy with lamotrigine. She was put on steroids and other supportive management. After a tempestuous course of 9 days in ICU, she made an eventful recovery.

Discussion

Lamotrigine, a chemically different newer antiepileptic, if rapidly titrated and used in conjunction with valproate can cause exfoliative dermatitis-like TEN, but at lower doses and as a monotherapy, female, post-partum, probably due to hormonal factors and strong association between HLA-B*1502 and AED (Antiepileptic drug)-induced SJS/TEN in patients of Asian ethnicity could be other contributing cause. Also, lesser use of lamotrigine in developing nations might have led to a lesser incidence of serious cutaneous adverse reactions. The SCORTEN (Severity-of-illness score for toxic epidermal necrolysis) is the most widely used system to standardize the evaluation of risk and prognosis in patients with TEN.

Conclusion

Though rare but TEN can occur following lamotrigine monotherapy. Prompt diagnosis, withdrawal of offending agent, and timely proper supportive care might help in lowering the mortality.

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Severe exfoliative dermatitis like SJS and TEN are less reported with lamotrigine as a monotherapy compared to aromatic anticonvulsants.

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The severe adverse cutaneous reaction following lamotrigine use may be overlooked as it is not used that frequently in developing nation.

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Prompt diagnosis, withdrawal of offending agent and proper supportive care can help prevent mortality in such case.

Drug Reaction with Eosinophilia and Systemic Symptom Syndrome Induced by Lamotrigine

Drug reaction with eosinophilia and systemic symptom (DRESS) syndrome is a type of severe adverse drug-induced reaction. Dermatologists should make a quick diagnosis and provide appropriate treatment for DRESS syndrome to reduce mortality rates, which can be as high as 10%. We present the case of a 47-year-old man with schizoaffective disorder treated with lamotrigine who developed DRESS syndrome to emphasize the importance of close observation of patients with drug eruption. He was consulted for erythematous maculopapular rashes on the trunk that developed 3 weeks after starting lamotrigine. A few days later, he developed generalized influenza-like symptoms. The skin rashes spread over his entire body, and the sense of itching was rapidly aggravated within a few days. Increased liver enzyme levels and significant eosinophilia were found on laboratory test results. His condition was diagnosed as DRESS syndrome, and he was treated with systemic and topical corticosteroids for 2 weeks.

Drug Hypersensitivity Syndrome Caused by Minocycline

Background:

Minocycline is a commonly prescribed drug for the treatment of acne. Its use is generally not associated with systemic side effects.

Objective:

To describe a case of minocycline-induced drug hypersensitivity syndrome in a 20-year-old Japanese woman.

Methods and Results:

Following 2 months of minocycline treatment, the patient developed skin lesions composed of exudative maculopapules, purpuratous macules, and target-like, erythema multiforme-like plaques over most of her body. In addition, she had fever, abnormal liver function tests, eosinophilia, and atypical lymphocytosis. Laboratory tests indicated no elevation of antibody titers against cytomegalovirus, Epstein-Barr virus, and human herpesvirus 6. Her ongoing exposure to minocycline was stopped, and treatment with oral prednisolone was begun. Her signs, symptoms, and laboratory abnormalities then began to resolve. Subsequently, the syndrome was observed to return briefly in response to an oral challenge with minocycline.

Conclusions:

Minocycline is able to elicit a drug hypersensitivity syndrome that can resemble infectious mononucleosis. This drug reaction can be treated effectively by cessation of exposure to this drug and steroid therapy.

Valproate as a risk factor for lamotrigine discontinuation

BACKGROUND

Although lamotrigine may be useful for treating bipolar depressive patients, some lamotrigine-associated adverse effects may prevent the continuation of treatment. The purpose of the present study was to identify risk factors for lamotrigine discontinuation after adjustment for several potential interactive factors.

METHODS

We examined tolerability in those who discontinued lamotrigine within 2 months of treatment and those who maintained lamotrigine for more than 2 months. Groups were examined separately because 6-8 weeks are necessary to titrate dose and drug eruptions can often occur within 2 months of treatment commencement.

RESULTS

Multiple regression analysis revealed that valproate combination was positively and significantly associated with lamotrigine discontinuation after adjustment for other factors.

LIMITATIONS

The limitations of the present study were retrospective observation and a relatively small number of subjects.

CONCLUSIONS

The present findings reconfirm that lamotrigine and valproate combination treatment may prevent the continuation of lamotrigine in some patients.

Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS) in an Adolescent Treated With Lamotrigine

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a hypersensitivity syndrome most commonly associated with antiepileptic agents, allopurinol, and sulfonamides. It is a severe adverse reaction associated with fever, rash, eosinophilia, lymphadenopathy, and internal organ involvement. We present the case of a 17-year-old Caucasian female with bipolar disorder type II and posttraumatic stress disorder treated with lamotrigine for a non-Food and Drug Administration-approved indication that developed DRESS syndrome at an initial dose higher than that recommended. Her symptoms were atypical in that she developed a rash with influenza-like symptoms that resolved after discontinuation of lamotrigine and returned 8 days later. She was hospitalized because of elevated liver enzymes and treated with corticosteroids. In patients presenting with rash and systemic symptoms, DRESS syndrome should be considered and treated appropriately to reduce mortality, which can be as high as 10%. Treatment includes withdrawal of the offending agent and corticosteroids.

Lamotrigine hypersensitivity syndrome and spiking Fever

We report a case of a 26 year old woman with rash, lymphadenopathy, liver enzyme abnormalities and spiking fever. She was diagnosed with drug-induced hypersensitivity syndrome (DHS) to lamotrigine. Spiking fever in relation to drug-induced hypersensitivity syndrome has not earlier been described in adults. Spiking fever is an important symptom of the wide spectrum of disease presentation. The syndrome is commonly referred to as either Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) or DHS. In accord with previous authors we see both syndromes as two ends of a spectrum, with a wide range of symptoms and presentations. Therefore we plea for unity in nomenclature.

Pathogenesis and Clinical Approaches to Anticonvulsant Hypersensitivity Syndrome: Current State of Knowledge

Anticonvulsant hypersensitivity syndrome (AHS) is a rare, but severe and potentially fatal, adverse reaction that occurs in patients who are treated with commonly used older anticonvulsant drugs (phenytoin, carbamazepine and phenobarbital) and/or with some newer agents (lamotrigine). Paediatric patients are at an increased risk for the development of AHS for the higher incidence of seizure disorder in the first decade of life. Hypersensitivity reactions range from simple maculopapular skin eruptions to a severe life-threatening disorder. AHS is typically associated with the development of skin rash, fever and internal organ dysfunctions. Recent evidence suggests that AHS is the result of a chemotoxic and immunologically-mediated injury, characterized by skin and mucosal bioactivation of antiepileptic drugs and by major histocompatibility complex-dependent clonal expansion of T cells. Early recognition of AHS and withdrawal of anticonvulsant therapy are essential for a successful outcome. In vivo and vitro tests can be helpful for the diagnosis that actually depends essentially on clinical recognition.

The variable clinical picture of drug-induced hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms in relation to the eliciting drug

Drug-induced hypersensitivity syndrome (DIHS)/drug rash with eosinophilia and systemic symptoms (DRESS) is a life-threatening adverse reaction characterized by skin rashes, fever, leukocytosis with eosinophilia or atypical lymphocytosis, lymph node enlargement, and liver or renal dysfunction. The syndrome develops 2 to 6 weeks after initiation of administration of a specific drug. It has been demonstrated that various herpesvirus reactivations, in addition to human herpesvirus 6, contribute to internal organ involvement and the relapse of symptoms observed long after discontinuation of the causative drugs. A better understanding of the interplay in the development of DIHS/DRESS has implications for safer and more efficient treatment of this syndrome.

Agranulocytosis following phenytoin-induced hypersensitivity syndrome

Phenytoin, one of the most common antiepileptic drugs, is a major cause of antiepileptic drug hypersensitivity syndrome (AHS), which is a rare but potentially fatal complication. We herein report a 5-year-old boy who developed unexpected agranulocytosis with fever approximately one week after recovering from the typical symptoms of AHS, characterized by fever, rash, lymphadenopathy, and hepatitis, but lacking eosinophilia or lymphocytosis. High-dose steroid therapy for the former symptoms of AHS, and immunoglobulin, granulocyte colony-stimulating factor, and cefepime for the latter agranulocytosis were successfully performed. This unexpected progression from AHS to agranulocytosis shortly after recovering from the former should be recognized as another risk of AHS, possibly leading to a life-threatening condition.

Lamotrigine-associated reversible severe hepatitis: a case report

INTRODUCTION

Anticonvulsant hypersensitivity syndrome is a severe idiosyncratic reaction to antiepileptic drugs. We report a case of a woman with lamotrigine-associated hepatitis who recovered spontaneously with supportive treatment.

CASE REPORT

A 43-year-old woman was being treated with oxcarbazepine for depression and was started on lamotrigine 2 weeks prior to her presentation. The patient then developed nausea and a generalized pruritic macular rash, and was found to have elevated liver enzymes, which peaked at AST, 6079 IU/L; ALT, 6900 IU/L; total bilirubin, 3.9 mg/dL(66.7 micromol/L); alkaline phosphatase, 149 IU/L; international normalized ration (INR), 1.9. The patient showed no signs of encephalopathy and her clinical examination was essentially normal except for very mild jaundice and a diffuse erythematous pruritic macular rash. The patient was hydrated and managed with supportive care. On the third day of hospitalization, her liver enzymes had improved substantially and she was discharged. At follow-up 1 month later the patient's liver enzymes were within the normal range.

DISCUSSION

We hypothesize that lamotrigine was directly responsible for the patient's rash and liver impairment given the time sequence of drug introduction and resolution of symptoms and liver enzyme abnormality once the drug was withdrawn. The patient suffered severe transaminitis when lamotrigine was added to oxcarbazepine, which resolved after termination of the medication and supportive management. We recommend monitoring the hepatic function in patients who have just been initiated on lamotrigine, especially if they develop jaundice.

Hepatotoxicity associated with antiepileptic drugs

BACKGROUND

Drug-induced liver injury associated with antiepileptic drugs (AED) is well recognized. The frequency of the most common AED is rare but the consequences can be very serious leading to death or liver transplantation due to acute liver failure induced by these drugs.

CLINICAL FEATURES

Hypersensitivity features are found in more than 70% of patients with phenytoin-induced liver injury, whereas this is only observed in 30% of carbamazepine-associated hepatotoxicity and very rarely with valproate (VPA)-induced liver injury.

PATHOPHYSIOLOGY

The underlying mechanisms behind hepatotoxicity induced by AED are not clear. Reactive metabolites from AED can, in some cases, lead to direct cytotoxicity and liver cell necrosis, whereas in other cases this may lead to neoantigen formation inducing immunoallergic mechanisms.

TREATMENT

No specific therapy is of proved value in severe hepatotoxicity due to AED. However, N-acetylcystein is an appropriate treatment in patients with clinically significant liver injury due to phenytoin and carbamazepine. In patients with VPA-associated liver injury, carnitine that is an important co-factor in the mitochondrial beta-oxidation of fatty acids is the recommended treatment. Early referral of patients with severe liver reactions and coagulopathy to liver transplant centers before encephalopathy can be the difference between liver transplantation and death.

Clinical efficacy of zonisamide in Lennox-Gastaut syndrome: Korean multicentric experience

PURPOSE

To evaluate the efficacy and safety of zonisamide (ZNS) as long-term adjunctive therapy in children with Lennox-Gastaut syndrome (LGS).

METHOD

We evaluated the seizure frequency, cognitive outcomes, and side effects of 62 LGS patients maintained on ZNS for at least 12 months in three tertiary centers.

RESULTS

Of the 62 LGS patients maintained on ZNS, 3 (4.8%) had 100% seizure control; 14 (22.6%) had >75% to <100% reduction in seizure frequency; 15 (24.2%) had >50% to <75% reduction in seizure frequency; 6 (9.7%) had >0% to <50% reduction in seizure frequency, and 24 (38.7%) had no seizure reduction. Seizure outcomes were not related to seizure types or etiologies. Adverse events included somnolence and anorexia, but all were transient and successfully managed by careful follow-up.

CONCLUSION

Our results indicate that adjunctive treatment with ZNS is safe and effective in pediatric LGS patients.

Rash and Liver Dysfunction Related to Lamotrigine Therapy

Objective:

To report a case of rash and liver dysfunction associated with lamotrigine treatment.

Case Summary:

An 81-year-old woman with a history of bipolar disorder presented to the emergency department with complaints of fever, chills, nausea, and headache. Two weeks prior to presentation, liver enzymes were normal. Lamotrigine 50 mg/day and sustained-release bupropion 200 mg/day were started after discontinuation of citalopram. The patient had previous exposure to bupropion and documented rash with exposure to penicillin and sulfa. On admission, laboratory tests revealed slightly elevated liver enzymes and slightly low serum albumin. All medications were continued. On hospital day 3, a diffuse maculopapular rash developed on the patient's chest, abdomen, neck, and upper extremities, which was pruritic and warm to the touch. Both lamotrigine and bupropion were discontinued. Liver enzymes increased to more than 3 times the upper limit of normal, and serum albumin decreased. Liver function tests improved on day 6, and the rash resolved.

Discussion:

Predictive risk factors associated with lamotrigine-induced rash and liver dysfunction include rapid dose titration, previously reported rash with other medications, age, and concurrent interacting medications. More serious adverse effects, such as Stevens–Johnson syndrome and fulminant hepatic failure, have also been associated with lamotrigine treatment. If rash appears at any time during treatment, lamotrigine must be discontinued. According to the Naranjo probability scale, an association between lamotrigine and rash and liver dysfunction could be considered probable in this case.

Conclusions:

A faster than recommended dose titration may lead to lamotrigine-induced adverse effects such as rash and liver dysfunction in patients with risk factors.

Antiepileptic drugs in the treatment of neuropathic pain

Antiepileptic drugs are an effective treatment for various forms of neuropathic pain of peripheral origin, although they rarely provide complete pain relief. Multiple multicentre randomised controlled trials have shown clear efficacy of gabapentin and pregabalin for postherpetic neuralgia and painful diabetic neuropathy. Theses drugs can be rapidly titrated and are well tolerated. Topiramate, lamotrigine, carbamazepine and oxcarbazepine are alternatives for the treatment of painful diabetic neuropathy, but should be titrated slowly. Carbamazepine remains the drug of choice for trigeminal neuralgia; however, oxcarbazepine and lamotrigine are potential alternatives. There is an apparent need for large-scale randomised controlled trials on the efficacy of antiepileptic drugs in neuropathic pain in general, and in cancer-related neuropathic pain and neuropathic pain of central origin in particular. Trials with long-term follow-up are required to establish the long-term efficacy of antiepileptic drugs in neuropathic pain. There is only limited scientific evidence to support the idea that drug combinations are likely to be more efficacious and safer than each drug alone; further studies are warranted in this area.

Possible Bioactivation Pathways of Lamotrigine

The anticonvulsant lamotrigine is associated with idiosyncratic drug reactions, especially skin rashes. Most idiosyncratic reactions are believed to be caused by reactive metabolites. Previous studies have found evidence that an arene oxide is formed in rats; however, when we incubated radiolabeled lamotrigine with rat liver microsomes virtually no covalent binding was detected, and the expected downstream phenolic metabolites are not observed in humans. Rare cases of agranulocytosis have been associated with lamotrigine therapy, and we found that lamotrigine is oxidized to two different N-chloro products by HOCl. The more reactive N-chloro metabolite forms an adduct with N-acetylhistidine, and covalent binding was observed when radiolabeled lamotrigine was incubated with myeloperoxidase/H(2)O(2)/Cl(-). Another lamotrigine metabolite is an N-oxide. If this N-oxide were sulfated, it might be sufficiently reactive to bind to protein. The synthetic N-sulfate reacted with N-acetylserine; however, no covalent binding was detected when the radiolabeled N-oxide was incubated with sulfotransferase. We also investigated the possibility that lamotrigine might be oxidized to a free radical by other peroxidases or oxidized by other enzymes such as prostaglandin H synthase or tyrosinase, but no evidence of oxidation was found, and lamotrigine did not cause any detectable increase in lipid peroxidation in vivo. In view of the virtual lack of covalent binding to hepatic microsomes and the lack of any other likely pathway leading to metabolic activation in the skin, it is possible that the parent drug rather than a reactive metabolite causes lamotrigine-induced skin rashes.

Recognition and Management of Severe Cutaneous Drug Reactions

Cutaneous drug reactions are among the most common types of adverse drug reactions. This article focuses on the recognition and management of severe cutaneous drug eruptions, including the drug-hypersensitivity syndrome, serum sickness-like reaction, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Cutaneous reactions are considered severe when they can result in serious skin damage or involve multiple organs. Some of these reactions can cause significant morbidity or death. Each may be confounded by diagnostic difficulties, confusion in ascertaining causality, and treatment challenges.

Idiosyncratic adverse reactions to antiepileptic drugs

Idiosyncratic drug reactions may be defined as adverse effects that cannot be explained by the known mechanisms of action of the offending agent, do not occur at any dose in most patients, and develop mostly unpredictably in susceptible individuals only. These reactions are generally thought to account for up to 10% of all adverse drug reactions, but their frequency may be higher depending on the definition adopted. Idiosyncratic reactions are a major source of concern because they encompass most life-threatening effects of antiepileptic drugs (AEDs), as well as many other reactions requiring discontinuation of treatment. Based on the underlying mechanisms, idiosyncratic reactions can be differentiated into (1) immune-mediated hypersensitivity reactions, which may range from benign skin rashes to serious conditions such as drug-related rash with eosinophilia and systemic symptoms; (2) reactions involving unusual nonimmune-mediated individual susceptibility, often related to abnormal production or defective detoxification of reactive cytotoxic metabolites (as in valproate-induced liver toxicity); and (3) off-target pharmacology, whereby a drug interacts directly with a system other than that for which it is intended, an example being some types of AED-induced dyskinesias. Although no AED is free from the potential of inducing idiosyncratic reactions, the magnitude of risk and the most common manifestations vary from one drug to another, a consideration that impacts on treatment choices. Serious consequences of idiosyncratic reactions can be minimized by knowledge of risk factors, avoidance of specific AEDs in subpopulations at risk, cautious dose titration, and careful monitoring of clinical response.

Anticonvulsant hypersensitivity syndrome: cross-reactivity with tricyclic antidepressant agents

BACKGROUND

Aromatic anticonvulsant agents such as carbamazepine and phenytoin can induce anticonvulsant hypersensitivity syndrome (AHS) at a frequency of 1 in 10,000 to 1 in 1,000 treated patients. The hypersensitivity syndrome is a potentially life-threatening adverse drug reaction with multiorgan involvement, and incidental reexposure must be strictly avoided. Patients and treating physicians must be informed and educated about the causal drug and its potential immunologic or toxicologic cross-reactivity with other compounds. It has been well established that for future antiepileptic drug therapy, carboxamides (carbamazepine and oxcarbazepine), phenytoin, and barbiturates (phenobarbital and primidone) have to be avoided owing to their high degree of cross-reactivity. Other anticonvulsant agents, such as valproic acid, benzodiazepines, and gabapentin, may be prescribed.

OBJECTIVES

To present the clinical data for and to describe the potential cross-reactivity between aromatic anticonvulsant and tricyclic antidepressant agents in patients with carbamazepine- and phenytoin-induced AHS.

METHODS

The knowledge of cross-reactivity among aromatic anticonvulsant agents mainly emerged from clinical experience and observations because diagnostic challenge tests are not advisable. Thirty-six patients with the diagnosis of AHS were instructed to contact our unit if the symptoms relapsed.

RESULTS

Despite better knowledge of AHS, one third of the patients had avoidable recurrences after exposure to cross-reactive drugs. Besides the known cross-reactivity among aromatic anticonvulsant agents, we observed a recurrence of the hypersensitivity syndrome in 5 patients after the administration of tricyclic antidepressant agents.

CONCLUSION

The important potential cross-reactivity between aromatic anticonvulsant and tricyclic antidepressant drugs should be brought to the attention of treating physicians.

Variability in the clinical pattern of cutaneous side-effects of drugs with systemic symptoms: does a DRESS syndrome really exist?

OBJECTIVE

To improve the definition of the various clinical patterns of patients with drug-induced cutaneous side-effects with systemic symptoms, and their possible relationships with the triggering medication, with the ultimate goal of helping in the identification of the causal drug in difficult situations when the patient is taking several drugs.

METHODS

Cases of drug-induced cutaneous side-effects associated with various systemic syndromes related to anticonvulsants (carbamazepine, phenytoin and phenobarbitone), minocycline, allopurinol, abacavir and nevirapine were collected retrospectively from the French Pharmacovigilance database (FPD) over a period of 15 years (1985-2000). The clinical patterns typical of the causative drugs were described and compared with data from the literature.

RESULTS

Two hundred and sixteen patients with symptoms and signs consistent with cutaneous drug reactions with systemic symptoms were reported to the FPD during this period of time. Their pattern was similar to published data for these drugs, with fever, cutaneous eruption, hepatic abnormalities and eosinophilia being the most prominent but inconstant symptoms. There are clues suggesting that some particular lesional patterns may exist for some drugs.

CONCLUSIONS

Although some trends emerge from these retrospective data, they suggest that no clear, unified outline can currently be defined for these multi-organ drug-induced reactions. Instead, a constellation of various symptoms and signs were recorded, that might be sorted in different patterns according to the causal drug, a finding that might indeed improve accurate identification of the causative drug in patients receiving several principal medications at a time. A national prospective study systematically collecting standardized data is required better to define the outlines of these severe adverse drug reactions and to evaluate prognostic data.

Lamotrigine-associated anticonvulsant hypersensitivity syndrome in bipolar disorder

Anticonvulsant hypersensitivity syndrome (AHS) is a rare but life-threatening adverse effect of aromatic anticonvulsants such as phenytoin, phenobarbital and carbamazepine, although there is extensive experience with AHS related to these anticonvulsants. Very few cases of lamotrigine-associated AHS have been reported in bipolar patients and most reported cases were published in non-psychiatric journals. The authors describe here the occurrence of an AHS in a 48-year-old bipolar woman who was treated with lamotrigine, valproic acid and venlafaxine for her depressive symptoms. She developed a high fever, generalized maculopapular rash, pancytopenia, pneumonitis and hepatitis after we added lamotrigine to valproate and venlafaxine. These adverse drug reactions resolved after the discontinuation of lamotrigine and valproate, and the administration of oral antihistamine and corticosteroid. Our case demonstrates that the most important steps in the management of lamotrigine-associated AHS are to recognize the disorder, discontinue the offending anticonvulsants, provide supportive care in an inpatient setting, and treat with antihistamine and steroids when appropriate.

Du rire aux larmes: pathological laughing and crying in patients with traumatic brain injury and treatment with lamotrigine

Pathologic laughter and crying (PLC) is the involuntary occurrence of laughter and crying in the absence of a corresponding change in affect. PLC resulting from structural brain damage in patients with traumatic brain injury can be the cause of substantial social dysfunction in these patients. The use of lamotrigine as an antiepileptic drug and mood stabilizer is well established; its use in PLC has been reported only once during treatment following a stroke. We present here four young patients with pathological laughter and/or pathological crying following traumatic brain injury who were successfully treated with lamotrigine. Data supporting the use of lamotrigine in the treatment of PLC following traumatic brain injury and the neuroanatomy of pathological laughing are briefly reviewed.

Lamotrigine for neuropathic pain

Lamotrigine is an antiepileptic drug that stabilizes neural membranes by blocking the activation of voltage-sensitive sodium channels and inhibiting the presynaptic release of glutamate. Full length reports of five open trials and six out of seven randomized controlled trials (plus two abstracts) have demonstrated the efficacy of lamotrigine in the treatment of various forms of neuropathic pain. The present drug profile provides a review of the pharmacologic properties of lamotrigine, the clinical evidence related to its efficacy and safety, and discusses the current and future role of the drug in the treatment of neuropathic pain.

Rash, fever, and neck pain in the office: is this a neurologic emergency?

Anticonvulsants, neuroleptics, and antispasticity agents are used with increasing frequency in the pediatric population. Each of the drugs discussed in this article has serious but potentially reversible adverse effects. Pediatric primary care providers must be aware of the potential emergencies associated with the use of these neurologic medications to provide prompt and effective treatment.

Syndrome d’hypersensibilité médicamenteuse à la lamotrigine

INTRODUCTION

Lamotrigine is an antiepileptic agent used in a wide range of seizure disorders among the elderly. In rare cases, it can induce a drug hypersensitivity syndrome (DHS).

CASES

DHS due to lamotrigine was observed in two patients (85 and 91 years-old). The first case was characterized by febrile erythema with eosinophilia and the second by isolated fever. Lamotrigine was replaced by sodium valproate for one patient. Both patients had satisfactory outcomes after discontinuing lamotrigine.

DISCUSSION

Lamotrigine can induce DHS that is clinically and biologically similar to the DHS observed with standard antiepileptic drugs. It may involve concomitant or consecutive treatment with other antiepileptic agents, in particular, valproate acid, which decreases lamotrigine clearance. Potentially serious and even fatal, these adverse reactions are to be feared in a population with multiple comorbidities and can cause harmful diagnostic mistakes. They are especially fearsome in geriatric populations with high epilepsy rates.

Skin reactions due to anti-epileptic drugs: several case-reports with long-term follow-up

In this study, the clinical findings and management of allergic skin reactions induced by the most used antiepileptic drugs, Lamotrigine (LMT) and Carbamazepine (CBZ), were evaluated. Lamotrigine is an antiepileptic drug recently released in several countries; it is effective for a variety of seizure types in adults and children, both as an add-on agent and in monotherapy, and it is generally well tolerated. Clinical and epidemiologic evidence suggest serious cutaneous reactions to antiepileptic drugs are more likely to occur during the first 8 weeks and they appear to increase when drugs are administered with other anticonvulsants, such as Valproate (VPA). We selected 10 patients who presented an idiosyncratic skin rash when treated with carbamazepine (8 patients) and lamotrigine (2 patients) administered as monotherapy, and we followed up on these patients for several years. Seven reactions were mild/severe cutaneous eruptions; one Toxic Epidermal Necrolysis, a case of Stevens-Johnson and a case of Hypersensitivity Syndrome. All severe skin drug reactions were induced by Carbamazepine. In five patients the AEDs were ceased abruptly (sometimes with the administration of a different molecule), tapered in four and continued unchanged in one. We conclude that the discontinuation of the drug with substitution with another is the most effective treatment and that corticosteroids are helpful in mild cutaneous reactions, while in severe skin reactions, such as Toxic Epidermal Necrolysis, corticosteroids are only a complementary therapy since intravenous immunoglobulins are the first choice treatment.

Children versus adults: pharmacokinetic and adverse-effect differences

Pharmacokinetic differences may play a part in the age-related differences in the incidence of adverse effects. The most common idiosyncratic reaction to lamotrigine (LTG) is rash, affecting 10-20% of patients. Risk factors are young age, concurrent valproate (VPA), high starting dose, and rapid escalation. In children, cytochrome P450 (CYP)-catalyzed metabolism is increased, and uridine diphosphate (UDP)-glucuronosyltransferase (UGT)-catalyzed metabolism is not significantly different from that in adults. A CYP-catalyzed arene oxide intermediate of LTG has been identified. The increase CYP metabolism of LTG in children could result in increased formation of the reactive metabolite and a higher incident of rash. Children often received higher milligram per kilogram doses compared with adults. The higher dose would cause an increased amount of LTG metabolized to the reactive arene oxide intermediate. VPA therapy is associated with a transient elevation in liver-function tests in 15-30% of patients and a rare, fatal hepatotoxicity. Most cases of VPA hepatotoxicity occurred in children younger than 2 years who had preexisting neurologic or other physical defects. Hypotheses regarding the pathogenesis of the hepatotoxicity include preexisting mitochondrial disease or inborn errors of metabolism, VPA inhibition of beta-oxidation, and toxicity from VPA metabolites VPA, 4-ene-VPA, and 2,4-diene-VPA. Infants and children have higher concentration ratios of 4-ene-VPA to VPA. Polytherapy with enzyme inducers increases the formation of the hepatotoxic metabolites. The role of underlying metabolic disorders associated with hepatodegeneration and intractable seizures without VPA is a major confounder in identifying risk factors and demonstrates the difficulty in separating underlying disease factors in rare idiosyncratic reactions.

Anticonvulsant hypersensitivity syndrome in children: incidence, prevention and management

Anticonvulsant hypersensitivity syndrome (AHS) is a rare, but potentially fatal, adverse reaction that occurs in patients, including children, who are treated with anticonvulsants. During metabolism of the anticonvulsant, toxic arene-oxide compounds are produced. AHS is associated with both cutaneous and systemic symptoms and is associated with multiorgan involvement. Liver damage, in particular, seems to be associated with fatal outcomes. The pathophysiology of AHS is still uncertain but it may be linked to a genetically determined inability to detoxify reactive drug metabolites. The prompt recognition of the first clinical signs of AHS, and the rapid withdrawal of the anticonvulsant, often avoids the progression of symptoms. Pharmacological treatment is essentially based on systemic corticosteroids in association with enteral nutrition, intravenous fluid augmentation, pain relief and ocular care. Intravenous immunoglobulins may also have a possible therapeutic role in some cases. Diagnostic tests, such as patch tests or in vitro assays, for AHS could help to identify patients at risk of developing the syndrome and could represent a first step of primary prevention when applied to relatives of patients.

Antiepileptic hypersensitivity syndrome: clinicians beware and be aware

Antiepileptic hypersensitivity syndrome is a serious idiosyncratic, non-dose-related adverse reaction reported to occur with phenytoin, phenobarbital, carbamazepine, primidone, and lamotrigine. The reaction usually develops 1 to 12 weeks after initiation of therapy with one of the above agents and is recognized by the classic triad of fever, rash, and internal organ involvement. Immediate discontinuation of the suspected anticonvulsant is essential for good outcome. Patients usually are managed supportively with hydration, antihistamines, H(2)-receptor blockers, and topical corticosteroids. In severe cases, the use of systemic corticosteroids may be necessary. The use of intravenous immune globulin should be limited to severe cases where Kawasaki disease or idiopathic thrombocytopenic purpura cannot be ruled out. Education of health care professionals and patients is imperative to improving outcomes and prevention of this reaction in the future.

Use of topiramate in childhood generalized seizure disorders

Topiramate is a sulfamate derivative of the naturally occurring monosaccharide D-fructose. It was initially approved in the United States as adjunctive therapy for partial seizures in 1997. However, there is increasing evidence that it is effective in the treatment of generalized seizures and epilepsy syndromes. Initially, open-label studies using topiramate as add-on therapy in children with refractory generalized seizure types were performed. These showed improvement in patients with the following generalized seizure types: typical and atypical absence, atonic, myoclonic, generalized tonic-clonic, and juvenile myoclonic epilepsy. Double-blind, placebo-controlled multicentered studies in patients with refractory primary generalized tonic-clonic seizures and epilepsy syndromes were performed. The median reduction in seizure frequency for primary generalized tonic-clonic seizures was 56.7% for topiramate and 9% for placebo. Additionally, 13.6% of topiramate-treated patients were primary generalized tonic-clonic seizure free for the study period. In the topiramate-treated juvenile myoclonic epilepsy patients, primary generalized tonic-clonic seizures were reduced > 50% in 73% of patients. Open-label extension showed that primary generalized tonic-clonic seizures were reduced >50% in 63% of topiramate-treated patients for > or = 6 months, and 16% were primary generalized tonic-clonic seizure free > or = 6 months. Accumulating evidence suggests that topiramate has a broad spectrum of antiepileptic effect. Moreover, life-threatening organ toxicity has not been attributed to topiramate. Topiramate is an effective treatment for refractory generalized seizure types and epilepsy syndromes encountered in children.

Efficacy, pharmacology, and adverse effects of antiepileptic drugs

This article discusses the factors involved in the appropriate selection of anticonvulsant medications. The clinical use of commonly used traditional antiepileptic drugs and the newly marketed antiepileptic drugs is discussed. This includes the specific indications for use, adverse effects, and dosing of each drug. Drug interactions, mechanisms of action, and pharmacological properties of each drug is also reviewed.

Antiepileptic hypersensitivity syndrome in children

OBJECTIVE

To assess clinical features and outcomes of childhood antiepileptic hypersensitivity syndrome (AHS). AHS is an idiosyncratic reaction to aromatic anticonvulsants that can result in severe multiorgan dysfunction and death.

METHODS

Children with suspected AHS (fever, rash, lymphadenopathy, liver dysfunction) were identified by an in-house computerized adverse drug event reporting system. The medical charts of children with suspected AHS were reviewed. A MEDLINE search (from 1966 to October 1999) was performed using the term antiepileptic hypersensitivity syndrome.

RESULTS

Fourteen of 36 children who experienced a rash, urticaria, pruritus, fever, or hepatotoxicity associated with aromatic anticonvulsants met the criteria for AHS (mean age 10.4 +/- 6.5 y; males to females 8:6, white to African-American to biracial 10:3:1). Eight patients were receiving phenytoin, six carbamazepine, and four phenobarbital alone or in combination. The mean time from exposure to development of symptoms was 23.0 +/- 14.8 days. In addition to rash and fever (present in all patients by definition), other common features of AHS were lymphocytosis (71.4%), elevated erythrocyte sedimentation rate (64.3%), elevated aminotransferases (64.3%), lymphadenopathy (57.1%), eosinophilia (42.8%, coagulopathy (42.8%), leukocytosis (35.7%), leukopenia (35.7%), hyperbilirubinemia (35.7%), and nephritis (7.1%). All children recovered except one, who died from complications of liver failure. Clinical outcome was simimlar between children who received systemic steroid therapy (n=5) and those who did not. Antiepileptics producing AHS were discontinued in all patients.

CONCLUSIONS

AHS can be fatal in children if not promptly recognized. Fever, rash, and hepatotoxicity should serve as presumptive evidence for AHS, which requires immediate discontinuation of an offending anticonvulsant.

Possible atypical cross-sensitivity between phenytoin and carbamazepine in the anticonvulsant hypersensitivity syndrome

Anticonvulsant hypersensitivity syndrome (AHS) is a rare but potentially life-threatening reaction that occurs in response to common anticonvulsants in predisposed individuals. It is often characterized by fever, rash, lymphadenopathy, hepatitis, and laboratory abnormalities. Consequently, it often is overlooked or even misdiagnosed by practitioners unfamiliar with AHS. Cross-sensitivity manifests frequently between phenytoin, phenobarbital, and carbamazepine as an exacerbation of presenting signs and symptoms. We report a case of AHS in a patient whose clinical features changed significantly when switching from phenytoin to carbamazepine. Physicians and pharmacists must become aware of the extreme variability in AHS manifestation so that the offending anticonvulsant regimen can be discontinued in a timely manner.