Anticonvulsant hypersensitivity syndrome to lamotrigine confirmed by lymphocyte stimulation in vitro

Anticonvulsant hypersensitivity syndrome (AHS) developing to lamotrigine, a non-aromatic anticonvulsant, has rarely been reported. We present a two-year-old boy with refractory epilepsy on valproic acid and lamotrigine therapy who developed fever and a maculopapular itchy rash. Blood investigations detected lymphocytosis and thrombocytopenia. With a presumptive diagnosis of AHS, lamotrigine was discontinued. The fever and rash resolved over the next three days and the child was discharged on valproic acid and clobazam. The diagnosis was confirmed by in vitro lymphocyte toxicity assay, which not only demonstrated increased cell death following exposure to lamotrigine, but also to the three first-line aromatic anticonvulsants: phenytoin, phenobarbital and carbamazepine. The potential of first-line aromatic anticonvulsants to cause AHS should be remembered in a patient who has developed AHS on exposure to lamotrigine. Timely recognition of this rare but potentially fatal drug reaction is important.     

Anticonvulsant hypersensitivity syndrome associated with Epstein-Barr virus reactivation

We describe a 59-year-old female with severe anticonvulsant hypersensitivity syndrome (AHS) associated with Epstein- Barr virus (EBV) infection. The causative drug was speculated to be carbamazepine. Recurrent EBV infection was demonstrated by the presence of anti-EBV early antigen IgM antibodies and anti-EBV nuclear antigen IgG antibodies. To our knowledge, only one case of drug hypersensitivity syndrome (DHS) associated with EBV has been reported in the English- language literature. Our case is the second report of EBV-associated DHS, which suggests that EBV infection may contribute to the pathogenesis of AHS in a few patients.     

Drug hypersensitivity to previously tolerated phenytoin by carbamazepine-induced DRESS syndrome

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome associated with anticonvulsant drugs is a rare but potentially life-threatening disease that occurs in response to arene oxide producing anticonvulsant such as phenytoin and carbamazepine. There have been many reports of cross reactivity among the anticonvulsants upon first exposure to the offending drugs. However, there has been few data describing the development of DRESS syndrome after switching medication from previously well-tolerated phenytoin to carbamazepine, and the induction of hypersensitivity to phenytoin by DRESS to carbamazepine. We experienced a case of a 40-yr-old man who had uncontrolled seizure that led to the change of medication from the long-term used phenytoin to carbamazepine. He developed DRESS syndrome after changing the drugs. We stopped carbamazepine and restored phenytoin for seizure control, but his clinical manifestations progressively worsened and he recovered only when both drugs were discontinued. Patch tests with several anticonvulsants showed positive reactions to both carbamazepine and phenytoin. Our case suggests that hypersensitivity to a previously tolerated anticonvulsant can be induced by DRESS to another anticonvulsant, and that the patch test may be a useful method for detecting cross-reactive drugs in anticonvulsant-associated DRESS syndrome.     

儿童抗癫痫药高敏综合征6例临床报告及文献复习

目的总结儿童抗癫痫药高敏综合征(AHS)的临床特点.方法报告6例儿童抗癫痫药高敏综合征及复习国内外文献,总结儿童AHS的临床特点.结果儿童AHS患者均有发热、皮疹及内脏损害,部分患者的皮疹表现为Stevens-Johson综合征(SJS)、中毒性表皮松解症(TEN),立即停用致病药物及应用糖皮质激素是治疗的关键.结论芳香族抗癫痫药(苯妥英钠、苯巴比妥及卡马西平)能导致儿童AHS.     

Phenytoin as an augmentation for SSRI failures: a small controlled study

BACKGROUND: Lithium augmentation of antidepressant effects in patients unimproved on antidepressants is well documented. We hypothesized that phenytoin, reported to have antimanic, antidepressant and prophylactic effects on affective disorder, might also augment in SSRI failures. METHODS: Twenty five patients were recruited and twenty had data sufficient for analysis between phenytoin and placebo in depression ratings. RESULTS: No effect was found. LIMITATIONS: This study was a small study. CONCLUSIONS: Lithium's ability to augment in antidepressant failures may not be shared with the anticonvulsant mood stabilizers.     

Fetal anticonvulsant syndrome and mutation in the maternal MTHFR gene

Around 6% of infants born to mothers taking anticonvulsants have malformations, including neural tube defects, and a further proportion show developmental delay in later childhood. Three commonly used anticonvulsants, carbamazepine, phenytoin and sodium valproate, interfere with folic acid metabolism. We investigated the common 677 C>T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in samples from 57 patients and their parents and 152 controls to determine its contribution to the risk of fetal anticonvulsant syndrome. The 677 C>T mutation frequency was significantly higher in the mothers than in the controls, but there was no significant difference in 677 C>T frequency in the patients or in the fathers. Genotype frequencies in the mothers were significantly different from controls, there being an excess of 677 C>T homozygotes. Amongst the patients, there was an apparent excess of heterozygotes (not statistically significant), and the fathers were not significantly different from controls. Mutation in the MTHFR gene in a mother taking sodium valproate, phenytoin or carbamazepine during pregnancy is associated with fetal anticonvulsant syndrome in her offspring. The skewed distribution of genotypes in the affected children probably reflects the association of fetal anticonvulsant syndrome with the maternal genotype.     

Conventional anticonvulsant drugs in the guinea-pig kindling model of partial seizures: effects of repeated administration

This study addressed the anticonvulsant effects of repeated administration of phenytoin, carbamazepine, phenobarbital, valproate, and ethosuximide in kindled guinea-pigs in order to further substantiate this novel model of partial seizures for the screening of future anticonvulsant drugs. Behavioral toxic effects were assessed at 30 min following drug administration using scores on a sedation/muscle relaxation rating index. In response to suprathreshold stimulation, the anticonvulsant efficacy of the drugs were evaluated from measurements of afterdischarge duration (ADD) and behavioral seizure severity (SS) during a repeated drug treatment schedule in kindled guinea-pigs. All drugs exerted slight to moderate sedative effects in guinea-pigs on our rating index. We found that phenytoin, carbamazepine, and phenobarbital exhibited effective anticonvulsant properties in kindled guinea-pigs by reducing both ADD and SS. We found that valproate consistently reduced ADD throughout the treatment schedule but failed to significantly reduce SS. Lastly, ethosuximide failed to exhibit effective anticonvulsant properties. Our results indicate that the guinea-pig kindling model correctly predicted the actions of these common anticonvulsant drugs in the treatment of partial seizures. Guinea-pig amygdala kindling appears to serve as a useful and valid model for partial epilepsy.     

Performance characteristics of four immunoassays for antiepileptic drugs on the IMMULITE 2000 automated analyzer

Carbamazepine, phenobarbital, phenytoin, and valproic acid are commonly used antiepileptic drugs that show complicated pharmacokinetic behavior Nonisotopic immunoassays are used routinely to monitor these drugs, and assay specificity is important to obtain accurate results. By using samples from subjects receiving each of these antiepileptic medications, competitive immunoassays for them were evaluated on an IMMULITE 2000 automated chemiluminescent analyzer (Diagnostic Products, Los Angeles, CA). Phenytoin assays were evaluated using an additional set of samples from patients with abnormal renal function. All 4 methods were linear, had imprecision of less than 10%, and compared well with other commercial immunoassays. A positive bias was observed for phenytoin measured in samples from uremic patients compared with a high-performance liquid chromatography reference method. The molar cross-reactivity of carbamazepine-10,11-epoxide was 12% in the carbamazepine assay. Phenytoin metabolites and fosphenytoin had substantial cross-reactivity in the phenytoin assay. All antiepileptic drug assays performed well and are suitable for use in monitoring patients receiving antiepileptic drug therapy. One possible exception is the phenytoin assay with samples from patients with renal insufficiency.     

Interference of carbamazepine and carbamazepine 10,11-epoxide in the fluorescence polarization immunoassay for tricyclic antidepressants: estimation of the true tricyclic antidepressant concentration in the presence of carbamazepine using a mathematical model

We evaluated effects of carbamazepine and its metabolite, carbamazepine 10,11-epoxide, on the measurement of tricyclic antidepressant (TCA) concentrations in serum using the fluorescence polarization immunoassay (FPIA). We determined apparent TCA concentrations in 30 patients who were receiving carbamazepine but no TCAs. Carbamazepine concentrations ranged from 1.4 to 20.9 microg/mL (5.9-88.4 micromol/L); the observed apparent TCA concentrations ranged from 31.8 to 130.1 ng/mL (113.4-463.9 micromol/L). When aliquots of the drug-free serum pool were supplemented with known concentrations of carbamazepine or its metabolite, we observed significant apparent TCA concentrations using the FPIA; however, interference of carbamazepine was more than 3-fold more than its metabolite. When serum pools prepared from patients receiving TCA but no anticonvulsant medications were supplemented with known amounts of carbamazepine or its metabolite, we observed falsely elevated TCA concentrations. We formulated an equation to calculate the apparent TCA concentration from known carbamazepine concentrations. If carbamazepine and TCAs are present in a specimen, the true TCA concentration can be estimated by subtracting the calculated TCA concentration (due to carbamazepine) from the observed TCA concentration as measured by the TCA FPIA. This mathematical modeling is feasible because TCAs, even at very high concentrations, showed no interference with the carbamazepine FPIA.     

HLA-B1502 is associated with carbamazepine induced Stevens–Johnson syndrome in North Indian population

The evidence of association between HLA-B^∗1502 and anticonvulsant induced Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) from the Indian population is scant. Patients with a history of SJS/TEN secondary to carbamazepine or phenytoin were enrolled. The control group comprised of patients who had received carbamazepine/phenytoin for ?6 months without any adverse cutaneous event. Low-resolution DNA typing for HLA-B and high resolution HLA-B^∗15 typing was performed. Seventeen patients with history of SJS/TEN secondary to carbamazepine (9) or phenytoin (8) and 50 tolerant controls (carbamazepine-37; phenytoin-13) were enrolled. The mean age of patients and controls was 33.9 ± 11.6 and 28.1 ± 9.9 years, respectively. HLA-B^∗1502 was observed in 2/9 (22.2%) carbamazepine-SJS/TEN patients and none of the 37 carbamazepine tolerant controls (p = 0.035). HLA-B^∗1502 was not observed in any of the 8 phenytoin-SJS/TEN patients or the 13 phenytoin tolerant controls. Our data suggests that HLA-B^∗1502 is a risk factor for carbamazepine induced SJS/TEN. Therefore, HLA-B^∗1502 testing should be performed prior to initiating carbamazepine in North Indian population.     

Do antidepressants cause folic acid depletion? A pilot study

Chronic administration of tricyclic antidepressants is common; folic acid depletion is a potential consequence adversely affecting the mental state. In a pilot study prior to research in the community, serum and red cell folate and serum vitamin B ₁₂ levels were measured in the following elderly psychiatric inpatients: 14 controls (patients not receiving any drugs with known antifolate activity), 11 receiving tricyclic antidepressants, 13 receiving antipsychotics (phenothiazines) and four receiving an anticonvulsant (carbamazepine). Patients on prolonged treatment with carbamazepine or phenothiazine drugs had lower concentrations of folate in serum and erythrocytes compared with controls; the decrease was statistically significant for the effect of phenothiazines on serum folate levels. Tricyclic antidepressants, which are in widespread use in the community, did not cause folate depletion during the first two years of treatment.     

Comparison of carbamazepine, phenobarbital, phenytoin, and primidone in partial and secondarily generalized tonic-clonic seizures

We conducted a 10-center, double-blind trial to compare the efficacy and toxicity of four antiepileptic drugs in the treatment of partial and secondarily generalized tonic-clonic seizures in 622 adults. Patients were randomly assigned to treatment with carbamazepine, phenobarbital, phenytoin, or primidone and were followed for two years or until the drug failed to control seizures or caused unacceptable side effects. Overall treatment success was highest with carbamazepine or phenytoin, intermediate with phenobarbital, and lowest with primidone (P less than 0.002). Differences in failure rates of the drugs were explained primarily by the fact that primidone caused more intolerable acute toxic effects, such as nausea, vomiting, dizziness, and sedation. Decreased libido and impotence were more common in patients given primidone. Phenytoin caused more dysmorphic effects and hypersensitivity. Control of tonic-clonic seizures did not differ significantly with the various drugs. Carbamazepine provided complete control of partial seizures more often than primidone or phenobarbital (P less than 0.03). Overall, carbamazepine and phenytoin are recommended drugs of first choice for single-drug therapy of adults with partial or generalized tonic-clonic seizures or with both.     

Withdrawal of anticonvulsant drugs in patients free of seizures for two years. A prospective study

We discontinued anticonvulsant drugs in 92 patients who had been free of seizures during two years of treatment with a single drug. All the patients had epilepsy that had previously been untreated, and had been randomly assigned to receive carbamazepine, phenytoin, or sodium valproate. Thirty-one patients relapsed, and 61 remained free of seizures. The mean duration of the follow-up in the patients remaining free of seizures was 35 months (range, 6 to 62). There was no significant difference between the relapse rate among adults (35 percent) and that among children (31 percent). Our results suggest that the number of seizures a patient had before control was achieved, the number of drugs tried as single-drug therapy, and the type of treatment withdrawn all influenced the outcome. Among the various types of seizures, complex partial seizures with secondary generalization carried the worst prognosis. In comparison, the risk of relapse was 65 percent lower in patients with generalized seizures and 97 percent lower in patients with complex or simple partial seizures in the absence of secondary generalized attacks. Among the four electroencephalographic classes, class 4 (abnormal before treatment and unchanged before withdrawal) carried the worst prognosis. The risk of relapse was 94 to 99 percent lower in patients in the other three electroencephalographic classes. Among the three anticonvulsants, withdrawal of sodium valproate carried the worst prognosis. In comparison, the odds of relapsing were 28 percent lower after withdrawal of phenytoin and 85 percent lower after withdrawal of carbamazepine. We conclude that withdrawal of anticonvulsant medication should be considered in patients free of seizures for two years.     

Alopecia Areata Universalis After Phenobarbital-Induced Anti-Convulsant Hypersensitivity Syndrome

Alopecia is an adverse effect in those patients taking aromatic anti-convulsant drugs but is rarely reported after discontinuing such medications in the convalescent status of anti-convulsant hypersensitivity syndrome (AHS). A 3-year-old boy developed alopecia areata (AA) universalis in the convalescent status of phenobarbital-induced AHS, compatible to the evidences of increased lymphocyte proliferation and increased dead cells percentages while his peripheral blood mononuclear cells were incubated with phenobarbital. Skin histology revealed peri-follicular, peri-bublar and supra-bublar lymphocyte infiltration. By searching for the key words AHS, alopecia areata (AA, punctuate absence of terminal scalp hair), AA totalis (complete absence of terminal scalp hair), and AA universalis (total loss of terminal scalp and body hair) using PubMed, only 2 cases, to date, developed alopecia in the convalescent status of phenobarbital-induced AHS. Among these 3 cases, all had favorable prognosis despite having jaundiced hepatitis. Their hair grew back after 2–3 months steroid therapy. Alopecia does rarely develop in the convalescent status of phenobarbital-induced AHS after stopping phenobarbital and its mechanism is related to lymphocyte infiltration into the peri-bulbar, supra-bulbar and peri-follicular regions.     

Human leukocyte antigen (HLA) and pharmacogenetics: screening for HLA-B*57:01 among human immunodeficiency virus-positive patients from southern Alberta

The field of pharmacogenetics is witnessing a growing interest in the role of the human leukocyte antigen (HLA) in manifestation of adverse drug reactions (ADR). Here we report a retrospective analysis of the association of HLA-B*5701 with abacavir hypersensitivity syndrome (AHS) in a large Canadian cohort of 489 human immunodeficiency virus-1-positive patients exposed to abacavir. A total of 3.7% of abacavir-exposed patients had developed AHS. Using polymerase chain reaction sequence-specific primer-based genotyping, the HLA-B*5701 allele was observed in 20 patients (4.1%). Of the 20 HLA-B*5701(+) abacavir-treated patients, 18 (90%) had developed AHS. Carriage of the HLA-B*5701 allele indicated a strong association with abacavir hypersensitivity (p < 0.0001; odds ratio = 6,934; 95% confidence interval = 321-149,735). HLA-B*5701 genotyping demonstrated high sensitivity, specificity, and positive and negative predictive values. The data derived from the study highlight the importance of engaging histocompatibility and immunogenetics laboratories in taking a lead in mapping other less characterized HLA and immunogenetic markers associated with ADRs.     

Activation of T cells by carbamazepine and carbamazepine metabolites

BACKGROUND: T-cell-mediated hypersensitivity is a rare but serious manifestation of drug therapy. OBJECTIVES: To explore the mechanisms of drug presentation to T cells and the possibility that generation of metabolite-specific T cells may provoke cross-sensitization between drugs. METHODS: A lymphocyte transformation test was performed on 13 hypersensitive patients with carbamazepine, oxcarbazepine, and carbamazepine metabolites. Serial dilution experiments were performed to generate drug (metabolite)-specific T-cell clones to explore the structural basis of the T-cell response and mechanisms of antigen presentation. 3-Dimensional energy-minimized structures were generated by using computer modeling. The role of drug metabolism was analyzed with 1-aminobenzotriazole. RESULTS: Lymphocytes and T-cell clones proliferated with carbamazepine, oxcarbazepine, and some (carbamazepine 10,11 epoxide, 10-hydroxy carbamazepine) but not all stable carbamazepine metabolites. Structure activity studies using 29 carbamazepine (metabolite)-specific T-cell clones revealed 4 patterns of drug recognition, which could be explained by generation of preferred 3-dimensional structural conformations. T cells were stimulated by carbamazepine (metabolites) bound directly to MHC in the absence of processing. The activation threshold for T-cell proliferation varied between 5 minutes and 4 hours. 1-Aminobenzotriazole, which inhibits cytochrome P450 activity, did not prevent carbamazepine-related T-cell proliferation. Substitution of the terminal amine residue of carbamazepine with a methyl group diminished T-cell proliferation. CONCLUSION: These data show that carbamazepine and certain stable carbamazepine metabolites stimulate T cells rapidly via a direct interaction with MHC and specific T-cell receptors. CLINICAL IMPLICATIONS: Some patients with a history of carbamazepine hypersensitivity possess T cells that cross-react with oxcarbazepine, providing a rationale for cross-sensitivity between the 2 drugs.     

Psychotic (delusional) depression: a meta-analysis of physical treatments.

Literature reviews have suggested that combination antidepressant/antipsychotic drug therapy and electroconvulsive therapy (ECT) are of comparable efficacy in treating psychotic depression, and distinctly superior to antidepressant alone or antipsychotic alone. We undertook a meta-analysis of 44 studies, and focussed on those three principal treatment options. There was a trend for ECT to be superior to combination drug therapy, with bilateral ECT being suggested as distinctly more effective than unilateral, and ECT was demonstrated to be significantly superior to tricyclic drug alone. Combination drug therapy ranked as more effective than antipsychotic alone and than antidepressant alone, but that greater efficacy was not significant.     

Assessment of lymphocyte and phagocytic cell function in healthy volunteers undergoing short-term phenytoin administration

The effect of short-term (2 weeks) administration of the anticonvulsant drug phenytoin on humoral and cellular immune function and phagocytic cell system activity was tested in nine healthy volunteers. No change either in the absolute or relative counts of leukocytes was found after drug treatment. Moreover, immunoglobulin serum concentration and lymphocyte subsets positive for OKT3, OKT4, OKT8, OKDRIA, OKB2, Leu 7, Leu 11a, anti-beta 2-microglobulin and antitransferrin monoclonal antibodies were not affected by phenytoin administration. A significant impairment of both polymorphonuclear neutrophil migrating activity and stimulated metabolism as measured by nitro blue tetrazolium reduction and superoxide anion generation was found after drug treatment or when phenytoin was added in vitro to the cells at concentrations lying within the anticonvulsant therapeutic range. Monocyte function was unaffected both after phenytoin administration and after direct application to the cells. The phenytoin-induced changes of polymorphonuclear neutrophil function was completely reverted within 2 weeks after drug withdrawal. The phenytoin-induced alterations of the phagocytic cell system are discussed in relation not only to the possible implications in the pathogenesis of adverse effects of anticonvulsant therapy but also to the potential therapeutic exploitation in immunologically mediated disorders.     

Manic state with carbamazepine therapy of seizures

A 40-year-old man developed an acute state of manic exultation when given carbamazepine for complex partial seizures. The symptoms subsided when carbamazepine was discontinued, but recurred when the drug was inadvertently given again. This observation does not accord with previous evidence of a beneficial psychotropic effect for carbamazepine in some epileptic patients and of some effect in the treatment of mania. Carbamazepine has been shown to have complex actions on multiple neurotransmitter and neuromodulator systems, and it is possible that paradoxical effects of this nature may occur in susceptible individuals, as has been found with other sedative and anticonvulsant agents. The patient recalled brief euphoric periods after seizures, which may suggest that carbamazepine exacerbated or prolonged preexisting cerebral dysfunction.