Anticonvulsant Hypersensitivity Syndrome: Lymphocyte Toxicity Assay for the Confirmation of Diagnosis and Risk Assessment

Antiseizure Medication-Induced Alopecia: A Literature Review

Background: Adverse effects of antiseizure medications (ASMs) remain one of the major causes of non-adherence. Cosmetic side effects (CSEs) are among the most commonly reported side effects of ASMs. In this context, alopecia is one of the CSEs that has a high intolerance rate leading to poor therapeutical compliance. Methods: We performed a literature review concerning alopecia as a secondary effect of ASMs. Results: There are 1656 individuals reported with ASM-induced alopecia. Valproate (983), lamotrigine (355), and carbamazepine (225) have been extensively reported. Other ASMs associated with alopecia were cenobamate (18), levetiracetam (14), topiramate (13), lacosamide (7), vigabatrin (6), phenobarbital (5), gabapentin (5), phenytoin (4), pregabalin (4), eslicarbazepine (3), brivaracetam (2), clobazam (2), perampanel (2), trimethadione (2), rufinamide (2), zonisamide (2), primidone (1), and tiagabine (1). There were no reports of oxcarbazepine and felbamate with drug-induced alopecia. Hair loss seen with ASMs was diffuse and non-scarring. Telogen effluvium was the most common cause of alopecia. A characteristic feature was the reversibility of alopecia after ASM dose adjustment. Conclusions: Alopecia should be considered one important adverse effect of ASMs. Patients reporting hair loss with ASM therapy should be further investigated, and specialist consultation is recommended.

No population left behind: Improving paediatric drug safety using informatics and systems biology

Adverse drugs effects (ADEs) in children are common and may result in disability and death. The current paediatric drug safety landscape, including clinical trials, is limited as it rarely includes children and relies on extrapolation from adults. Children are not small adults but go through an evolutionarily conserved and physiologically dynamic process of growth and maturation. Novel quantitative approaches, integrating observations from clinical trials and drug safety databases with dynamic mechanisms, can be used to systematically identify ADEs unique to childhood. In this perspective, we discuss three critical research directions using systems biology methodologies and novel informatics to improve paediatric drug safety, namely child versus adult drug safety profiles, age-dependent drug toxicities and genetic susceptibility of ADEs across childhood. We argue that a data-driven framework that leverages observational data, biomedical knowledge and systems biology modelling will reveal previously unknown mechanisms of pediatric adverse drug events and lead to improved paediatric drug safety.

Evaluation of Lymphocyte Transformation Test Results in Patients with Delayed Hypersensitivity Reactions following the Use of Anticonvulsant Drugs

BACKGROUND/AIM

Administration of the anticonvulsant drugs phenobarbital, phenytoin, carbamazepine and lamotrigine can be associated with severe hypersensitivity reactions. The lymphocyte transformation test (LTT) is a method to determine which drug has caused the hypersensitivity reaction. This study was done to evaluate the results of LTT in patients with delayed hypersensitivity reactions following the administration of anticonvulsants.

METHODS

Twenty-four patients with hypersensitivity reactions, e.g. drug-induced hypersensitivity syndrome/drug rash and eosinophilia with systemic symptoms (DIHS/DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN), following the administration of anticonvulsant drugs, and 24 patients who had used anticonvulsant drugs but did not have hypersensitivity reactions (the control group) were included in this study. Peripheral blood mononuclear cells were isolated. The cells were stimulated with the drugs, phytohemagglutinin as a mitogen and Candida as an antigen (positive controls). Lymphocyte proliferation was measured using the BrdU proliferation assay kit (Roche, Germany). The stimulation index was calculated as the mean ratio of the OD of stimulated cells divided by the OD of unstimulated cells. The results in the case and control groups were compared.

RESULTS

Of 24 patients in the test group, 14 (58.3%) had positive LTT results and 10 (41.7%) had negative results. Among patients in the control group, 1 (4.2%) had a positive LTT result and 23 (95.8%) had negative results. Among the patients who had received carbamazepine and phenytoin, there was a significant difference between the results of LTT in the case and control groups (p = 0.002 and p = 0.028, respectively). Although patients receiving lamotrigine and phenobarbital had more positive LTT results in the case group than in the control group, these differences were not statistically significant. The sensitivity, specificity, positive predictive value and negative predictive value of LTT were 58.4, 95.8, 93.3 and 69.9%, respectively.

CONCLUSIONS

Considering the significant difference in LTT results between the case and control groups in patients receiving carbamazepine and phenytoin, and not observing such a difference in patients receiving phenobarbital and lamotrigine, LTT results are more valuable for the diagnosis of hypersensitivity reactions following the administration of carbamazepine and phenytoin. The LTT has good specificity but low sensitivity for the diagnosis of drug hypersensitivity reactions.

Cutaneous Adverse Drug Reactions in Dogs Treated with Antiepileptic Drugs

Epilepsy is one of the most common neurologic disorders in dogs and life-long treatment with antiepileptic drugs (AED) is frequently required. Adverse events of AED targeting the skin are only rarely reported in veterinary medicine and the true incidence and spectrum of cutaneous reactions in epileptic dogs remains unknown. In this study, we hypothesized that cutaneous reactions commonly occur in epileptic dogs and are related to AED treatment. A retrospective case review of 185 dogs treated for epilepsy identified 20.0% with simultaneous appearance of dermatologic signs. In a subsequent prospective case investigation (n = 137), we identified newly appearing or distinct worsening of skin lesions following initiation of AED therapy in 10.9% of dogs treated for epilepsy (95% CI 6.8–17.7%). Cutaneous lesions were classified as probably drug-induced in 40.0% of these cases. Patch testing and intradermal testing were further investigated as potential diagnostic methods to confirm AED hypersensitivity. They were of high specificity but sensitivity and positive predictive value appeared inappropriate to recommend their routine use in clinical practice.

Hepatoprotective and antioxidant activity of N-acetyl cysteine in carbamazepine-administered rats

Objectives:

The present study evaluates the hepatoprotective activity of N-acetyl cysteine (NAC) against carbamazepine (CBZ)-induced hepatotoxicity.

Materials and Methods:

Rats were treated with CBZ (50 mg/kg p.o.) and CBZ supplemented with NAC 50, 100 and 200 mg/kg for 45 days, after which blood samples were collected and subjected to liver function tests. Animals were killed, liver was separated, weighed and the levels of antioxidants and liver enzymes were estimated. In addition, histopathological investigation was also performed.

Results:

Serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate (SGOT) transaminase, alkaline phosphatase (ALP), bilirubin, lipid peroxidation, absolute and relative liver weights were significantly (P < 0.05) elevated, whereas serum levels of albumin, total protein and body weight were decreased in the CBZ-treated animals. CBZ also produced vacuolar degeneration, centrilobular congestion and hepatic necrosis as evidenced from histopathological report. NAC significantly reduced the levels of serum transaminase, ALP, bilirubin and liver weight and increased the levels of total protein, albumin and body weight.

Conclusion:

It was observed that NAC increased the glutathione (GSH) content, reduced lipid peroxidation and reversed the CBZ-induced histopathological abnormalities. CBZ-induced hepatotoxicity may be due its toxic epoxide metabolite-induced oxidative stress.

Levetiracetam-induced drug reaction with eosinophilia and systemic symptoms syndrome

OBJECTIVE

To describe a case of levetiracetam-induced drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome.

CASE SUMMARY

A 31-year-old white male with a low-grade astrocytoma presenting with tonic-clonic seizures was treated with levetiracetam 1 g twice daily and dexamethasone (initial dosage 12 mg/day, tapered down to 2 mg/day). On day 45 after levetiracetam initiation, dexamethasone was discontinued and levetiracetam continued. The patient developed fever and dyspnea on day 46 and was admitted to the hospital on day 49. A chest X-ray showed bilateral pulmonary interstitial infiltrates, and laboratory tests showed elevated lactate dehydrogenase (LDH; 288 U/L [reference range <204]), ferritin (223 ng/mL [13-178]), and C-reactive protein (CRP; 3.1 mg/dL [<0.5]). Neurologic fever was suspected and the reinitiation of dexamethasone at 6 mg/day was followed by improvement of all symptoms; the patient was discharged on day 55 with dexamethasone 4 mg/day for 2 more days. On day 59, 2 days after the withdrawal of dexamethasone for the second time, the patient presented with a pruritic erythematous maculopapular rash along with recurrence of fever and dyspnea, and was admitted to the hospital. A chest X-ray showed reappearance of the bilateral pulmonary interstitial infiltrates, and laboratory tests showed impaired liver function (alanine aminotransferase 60 U/L [reference range <56], aspartate aminotransferase 53 U/L [<30], LDH 516 U/L, ferritin 419 ng/mL, and CRP 2.6). A diagnosis of DRESS syndrome was suspected and levetiracetam was discontinued. Upon levetiracetam withdrawal, the patient's symptoms resolved by day 66, and radiological images showed resolution of the interstitial infiltrate by day 68. The patient was discharged on day 68. Low-grade fever persisted until day 71, with no other symptoms. During a 2-month follow-up period, liver function test results returned to normal.

DISCUSSION

DRESS is a hypersensitivity reaction to several drugs, mainly antiepileptic drugs (AEDs), characterized by cutaneous, hematologic, and visceral involvement. Levetiracetam is structurally and pharmacologically unrelated to other AEDs. Previously, only one case of levetiracetam-induced DRESS syndrome had been reported, which required corticosteroids to control symptoms. We describe a case of levetiracetam-induced DRESS syndrome presenting with pneumonitis and hepatitis that resolved with levetiracetam withdrawal. Our patient was classified as a definitive DRESS case according to the RegiSCAR scoring system, which grades DRESS cases. According to the Naranjo probability scale, the adverse drug reaction was considered probable.

CONCLUSIONS

Although levetiracetam is usually well tolerated, clinicians should be aware of the potential for it to cause DRESS syndrome.

The DRESS syndrome: a literature review

The Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) is a severe adverse drug-induced reaction. Diagnosing DRESS is challenging due to the diversity of cutaneous eruption and organs involved. We used the RegiSCAR scoring system that grades DRESS cases as "no," "possible," "probable," or "definite" to classify cases reported in the literature. We also analyzed the clinical course and treatments of the cases. A total of 44 drugs were associated with the 172 cases reported between January 1997 and May 2009 in PubMed and MEDLINE. The most frequently reported drug was carbamazepine, and the vast majority of cases were classified as "probable/definite" DRESS cases. Hypereosinophilia, liver involvement, fever, and lymphadenopathy were significantly associated with "probable/definite" DRESS cases, whereas skin rash was described in almost all of the cases, including "possible cases." Culprit drug withdrawal and corticosteroids constituted the mainstay of DRESS treatment. The outcome was death in 9 cases. However, no predictive factors for serious cases were found. This better knowledge of DRESS may contribute to improve the diagnosis and management of this syndrome in clinical practice.

Anticonvulsant hypersensitivity syndrome: Identification and management

Anticonvulsant hypersensitivity syndrome is a rare and potentially life-threatening delayed-type immune reaction with few proven treatments beyond early recognition and immediate discontinuation of the causative drug. Intravenous immunoglobulin has been shown in some uncontrolled studies to hasten recovery and may prove safer than systemic corticosteroid therapy, which carries a significant risk for increased mortality from sepsis. Identification and counseling of at-risk patients through knowledge of potential drug cross-sensitivity and familial susceptibility may help prevent this dangerous idiosyncratic drug reaction.

Type 1 diabetes mellitus in a child with phenobarbital hypersensitivity syndrome

OBJECTIVE

To report a case of type 1 diabetes mellitus (T1DM) in a child with phenobarbital hypersensitivity syndrome with an emphasis on the clinical presentation, diagnostic modalities and treatment options.

CASE SUMMARY

A 5-yr-old girl developed fever, rash and hepatic inflammation after receiving phenobarbital. Infection and connective tissue diseases were excluded and an adverse event following phenobarbital administration [anticonvulsant hypersensitivity syndrome (AHS)] was considered. Clinical manifestation was somewhat improved after systemic hydrocortisone and other antiallergic drugs were administrated. However, polyuria, polydipsia, dehydration, severe metabolic acidosis with increased anion gap and hyperglucosemia were found about 4 weeks after stopping phenobarbital. Increased blood ketone and glycosylated hemoglobin (HbA1c), and decreased blood insulin and C-peptide confirmed the diagnosis of T1DM. Insulin was used and gamma-immunoglobulin was administered on the 25th day after admission. Since then, clinical symptoms and signs improved significantly and the patient was discharged on the 45th day after admission. Postdischarge course was uneventful and the patient is well with sequential HbA1c of 7.3% 1 month after discharge.

CONCLUSIONS

AHS should be suspected in patients who develop unexplained systemic manifestations following exposure to aromatic antiepileptics, including phenobarbital. The timely recognition and treatment with corticosteroids and immunoglobulin is required and useful. The potential damage of beta-cells should be considered in patients with AHS.

Aromatic antiepileptic drugs and mitochondrial toxicity: effects on mitochondria isolated from rat liver

Idiosyncratic hepatotoxicity is a well-known complication associated with aromatic antiepileptic drugs (AAED), and it has been suggested to occur due to the accumulation of toxic arene oxide metabolites. Although there is clear evidence of the participation of an immune process, a direct toxic effect involving mitochondria dysfunction is also possible. The effects of AAED on mitochondrial function have not been studied yet. Therefore, we investigated, in vitro, the cytotoxic mechanism of carbamazepine (CB), phenytoin (PT) and phenobarbital (PB), unaltered and bioactivated, in the hepatic mitochondrial function. The murine hepatic microsomal system was used to produce the anticonvulsant metabolites. All the bioactivated drugs (CB-B, PB-B, PT-B) affected mitochondrial function causing decrease in state three respiration, RCR, ATP synthesis and membrane potential, increase in state four respiration as well as impairment of Ca2+ uptake/release and inhibition of calcium-induced swelling. As an unaltered drug, only PB, was able to affect mitochondrial respiration (except state four respiration) ATP synthesis and membrane potential; however, Ca2+ uptake/release as well as swelling induction were not affected. The potential to induce mitochondrial dysfunction was PT-B>PB-B>CB-B>PB. Results suggest the involvement of mitochondrial toxicity in the pathogenesis of AAED-induced hepatotoxicity.

In vivo pharmacological effects of JZP-4, a novel anticonvulsant, in models for anticonvulsant, antimania and antidepressant activity

JZP-4 is a potent calcium and sodium channel blocker, which is currently being evaluated in patients as an anticonvulsant and mood stabilizer. In the current studies, JZP-4 was evaluated in a variety of animal models for anticonvulsant, antimania and antidepressant activity. In the mouse and rat maximal electroshock models, JZP-4 was slightly more potent than LTG. In the mouse pentylenetetrazole induced seizures model, JZP-4 was approximately twice as potent as lamotrigine in prolonging the time to clonus. In the mouse 6-Hz model for drug resistant or refractory epilepsy, JZP-4 had potent anticonvulsant activity at all current intensities, whereas LTG was active at only the lowest current intensity. In the mouse amphetamine-chlordiazepoxide model for antimanic effects, JZP-4, but not LTG, produced dose-related and significant effects at 3 and 10 mg/kg i.p. In the rat forced swim model of antidepressant activity, JZP-4 (30 mg/kg i.p.) produced a significant reduction in immobility and an increase in climbing behavior. LTG (30 mg/kg i.p.) produced similar effects but these effects did not achieve statistical significance. The specificity of this antidepressant response was confirmed in the rat locomotor test. In this test, JZP-4 produced dose-related and significant reductions in locomotor activity, indicating that it was not a CNS stimulant. LTG produced no significant effects in the rat locomotor test. The studies have demonstrated that JZP-4 has greater potency and efficacy than LTG in models of refractory epilepsy, antidepressant activity and antimania activity. The variance between the effects of LTG and JZP-4 may be related to the greater potency at sodium channels or the additional pharmacological actions of JZP-4 on calcium channels.

Anticonvulsant Hypersensitivity Syndrome: Implications for Pharmaceutical Care

Anticonvulsant hypersensitivity syndrome (AHS) is a delayed adverse drug reaction associated with the use of aromatic anticonvulsant drugs. It has been most commonly reported with the use of phenytoin, carbamazepine, and phenobarbital. Although its occurrence is rare, 1 in every 1000-10,000 exposures, AHS is a serious adverse event often resulting in hospitalization and even death. The clinical manifestations of AHS include a triad of symptoms consisting of dermatologic rashes, fever, and evidence of systemic organ involvement. Diagnosis is most frequently based on the recognition of this triad of symptoms and clinical judgment. The exact mechanism of AHS remains to be determined but is thought to have at least three components: deficiency or abnormality of the epoxide hydroxylase enzyme that detoxifies the metabolites of aromatic amine anticonvulsants, associated reactivation of herpes-type viruses, and ethnic predisposition with certain human leukocyte antigen subtypes. Arene oxides, the toxic intermediaries in the metabolism of anticonvulsant drugs, can accumulate and directly bind to macromolecules, causing cell death, as well as act as prohaptens that bind to T cells, initiating an immune response and systemic reactions. Management of AHS primarily includes discontinuation of the associated anticonvulsant drug. Systemic corticosteroids are usually required for full recovery. An important issue regarding AHS is the cross-sensitivity among aromatic anticonvulsant drugs, which has been reported to be 40-80%. This means that patients with a history of AHS should avoid further use of any aromatic anticonvulsant drug. In addition, a familial association with AHS exists, and family members of the patient with AHS should be educated that they may be at increased risk for developing AHS if they use aromatic anticonvulsant drugs. Anticonvulsant drugs that are generally considered safe are valproic acid and benzodiazepines. Other nonaromatic anticonvulsant drugs should also be acceptable. Pharmacists as health care providers can play an important role in the diagnosis, treatment, and prevention of AHS.

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.

Probable Anticonvulsant Hypersensitivity Syndrome Due to Fosphenytoin in a Pediatric Patient with Streptococcus pneumoniae Meningitis

An 8-year-old previously healthy girl with Streptococcus pneumoniae meningitis developed probable anticonvulsant hypersensitivity syndrome (AHS) within 5 days of starting fosphenytoin. She experienced fever, rash, periorbital edema, profound hepatotoxicity and coagulopathy. Her sudden and dramatic rise in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to greater than 80 times the upper limit of normal in combination with an elevated INR were very concerning. Mortality from AHS has been correlated with the degree of hepatic involvement. Fosphenytoin was immediately discontinued and, within 48 hours, AST, ALT and INR began to decrease and were within normal limits by hospital day 23. Prompt recognition of probable AHS and immediate discontinuation of fosphenytoin resulted in an abrupt reversal of clinical signs and laboratory values associated with potential hepatic failure in a pediatric patient.

Anticonvulsant hypersensitivity syndrome: a review

Anticonvulsant hypersensitivity syndrome (AHS), characterised by fever, rash and internal organ involvement, is a rare, but potentially fatal adverse event that occurs most commonly with first-line aromatic anticonvulsants, but can also occur with non-aromatic anticonvulsants such as lamotrigine and valproic acid. AHS can begin anywhere from 1 to 12 weeks after commencement of therapy and has been estimated to occur at a frequency of 1/1000 to 1/10,000 exposures. Its true incidence, however, remains unknown due to under-reporting. The disease has protean manifestations mimicking several other conditions, and the diagnosis is thus difficult. Several hypotheses have been put forward to explain the pathogenesis of AHS. These include accumulation of toxic metabolites, graft versus host disease, antibody production and viral infections. The one based on toxic metabolites has found the greatest acceptance, perhaps due to the fact that it can be proven by an in vitro test; the lymphocyte toxicity assay. Discontinuation of the offending agent with supportive, symptomatic therapy forms the mainstay of management of AHS. In addition, counselling of both the patient and first degree relatives for susceptibility to AHS is an important aspect of management. In the last decade, several new anticonvulsants have been introduced for epilepsy. In addition, for resource-poor countries, inexpensive and effective first-line drugs such as phenytoin and phenobarbitone will continue to remain important treatment options. Thus, the problem of AHS will continue, and attempts should be made to further understand the molecular basis of and individual susceptibility to AHS. Adverse event monitoring programs must also actively seek AHS reports to estimate its true incidence.

Epidemiology of hypersensitivity drug reactions

PURPOSE OF REVIEW

Hypersensitivity drug reactions are but one of the many different types of adverse drug reactions. They may be potentially life-threatening, prolong hospitalization, affect drug prescribing patterns of physicians and result in socioeconomic costs. This review summarizes current knowledge on the incidence, prevalence, mortality and risk factors for these reactions in different populations.

RECENT FINDINGS

Hypersensitivity reactions represent about one third of all adverse drug reactions. Adverse drug reactions affect 10-20% of hospitalized patients and more than 7% of the general population. Severe reactions including anaphylaxis, drug hypersensitivity syndromes, Stevens Johnson syndrome and toxic epidermal necrolysis are also associated with significant morbidity and mortality. Although several risk factors have been identified, their clinical importance has not been fully understood. Future progress in immunogenetics and pharmacogenetics may help identify populations at risk for specific types of reactions.

SUMMARY

Well designed epidemiological studies on hypersensitivity drug reactions are lacking as most studies have been on adverse drug reactions. Such studies will be helpful in identifying patients at risk of developing such reactions, in particular severe reactions, and implementing early preventive measures.