Anticonvulsant Hypersensitivity Syndrome: Implications for Pharmaceutical Care

Presumptive phenobarbital-induced systemic lupus erythematosus in a domestic dog

CASE DESCRIPTION

We describe a case of presumptive acquired systemic lupus erythematosus secondary to phenobarbital administration in a dog, which resolved with withdrawal of the drug.

CLINICAL FINDINGS

A 3.5 year-old poodle presented to a veterinary teaching hospital for Tier 1 idiopathic epilepsy and was treated with phenobarbital. The dog experienced fever, multiple cytopenias, and proteinuria in conjunction with a positive antinuclear antibody (ANA) titer.

DIAGNOSTICS

Serial CBCs, urine protein : creatinine ratios, and sternal bone marrow aspirates were performed to evaluate improvement.

TREATMENT AND OUTCOME

Phenobarbital was withdrawn and levetiracetam initiated. All abnormalities resolved with supportive care, without initiation of immunosuppressive drugs. All cytopenias and proteinuria resolved and ANA test results became negative within 3 months. The patient recovered and did well clinically.

CLINICAL RELEVANCE

Systemic lupus erythematosus is a disease of multiple autoimmune syndromes occurring concurrently or sequentially in conjunction with the presence of circulating ANA. It has been well described in dogs as an idiopathic condition, but in human medicine may occur secondary to drug reactions (drug-associated lupus) including as a reaction to phenobarbital. The findings in our case are consistent with the criteria for drug-induced lupus in humans and we suggest it as the first report of phenobarbital-induced lupus in a dog.

Investigation of cross-reactivity between phenobarbital and levetiracetam in children with epilepsy: A prospective, observational multicenter study

Objectives

Pharmaceutical allergic reactions due to antiseizure medications (ASMs) are one of the major concerns in the management of patients. Finding an alternative ASM which does not cause allergic reactions and has acceptable effectiveness can be difficult. In this regard, the present study attempts to investigate the cross-reactivity between phenobarbital and levetiracetam in children under treatment for seizure control.

Materials & Methods

The present study is a prospective, observational independent assessor study. 30 children with epilepsy who were hypersensitive to phenobarbital therapy were studied. In order to evaluate the cross-reactivity of the drugs, levetiracetam replaced phenobarbital to control seizure. Within 6 months, any allergic reactions and seizure recurrences were evaluated in the patients.

Results

53 % of the children in this study were female. The mean age of patients was 42.4 months. In patients' follow up no cross-reactive responses were observed in any of the patients. Seizure recurrence rate was 30 % in the first six months of follow up that with increasing dosage in the second six months of follow-up, decreased to 10 %.

Conclusion

Based on the results of this study, in children with epilepsy controlled by phenobarbital if allergic reactions to phenobarbital occur, levetiracetam may be used as a suitable alternative medicine.

Drug reaction with eosinophilia and systemic symptoms: An emergency medicine focused review

INTRODUCTION

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe drug reaction associated with potentially severe morbidity and mortality.

OBJECTIVE

This narrative review evaluates the pathogenesis, diagnosis, and management of DRESS for emergency clinicians.

DISCUSSION

DRESS is a severe hypersensitivity reaction which can involve multiple organ systems, including the skin, lymphatic system, lungs, kidneys, and heart. Treatment is primarily supportive care combined with removal of the offending agent and initiation of corticosteroids. Additional options include cyclophosphamide, cyclosporine, intravenous immunoglobulin, and N-acetylcysteine.

CONCLUSION

It is important for the emergency clinician to be aware of the diagnosis and management of DRESS in order to best optimize care for these patients.

Phenobarbital-induced autoimmune haemolytic anaemia, thrombocytopenia and peripheral lymphadenomegaly due to reactive lymphoid hyperplasia in a cat

Case summary

A female neutered domestic longhair cat, aged 1 year and 5 months, presented with lymphadenomegaly and anaemia following therapy with phenobarbital for idiopathic epilepsy. Physical examination revealed pale pink mucous membranes and peripheral lymphadenomegaly. Haematology showed a regenerative anaemia (haematocrit 19.3%, reticulocyte count 118.08 ×10⁹/l), and saline agglutination was positive. Infectious disease screening was negative and lymph node cytology was consistent with reactive lymphoid hyperplasia. A diagnosis of phenobarbital-induced reactive lymphoid hyperplasia and immune-mediated anaemia was suspected. Complete resolution of the lymphadenomegaly and anaemia was documented within 4 weeks of phenobarbital discontinuation.

Relevance and novel information

There are limited case reports of phenobarbital-induced haematological changes and lymphadenomegaly; however, the combination has not previously been reported in cats and is similar to the rare but significant syndrome in humans known as ‘anticonvulsant hypersensitivity syndrome’. Anticonvulsant hypersensitivities should be considered as a potentially serious, yet reversible, sequela to phenobarbital treatment that may be mistaken for more severe illness such as neoplasia.

Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction

Several generations of antiepileptic drugs (AEDs) are available in the market for the treatment of seizures, but these are amalgamated with acute to chronic side effects. The most common side effects of AEDs are dose-related, but some are idiosyncratic adverse drug reactions (ADRs) that transpire due to the formation of reactive metabolite (RM) after the bioactivation process. Because of the adverse reactions patients usually discontinue the medication in between the treatment. The AEDs such as valproic acid, lamotrigine, phenytoin etc., can be categorized under such types because they form the RM which may prevail with life-threatening adverse effects or immune-mediated reactions. Hepatotoxicity, teratogenicity, cutaneous hypersensitivity, dizziness, addiction, serum sickness reaction, renal calculi, metabolic acidosis are associated with the metabolites of drugs such as arene oxide, N-desmethyldiazepam, 2-(1-hydroxyethyl)-2-methylsuccinimide, 2-(sulphamoy1acetyl)-phenol, E-2-en-VPA and 4-en-VPA and carbamazepine-10,11-epoxide, etc. The major toxicities are associated with the moieties that are either capable of forming RM or the functional groups may itself be too reactive prior to the metabolism. These functional groups or fragment structures are typically known as structural alerts or toxicophores. Therefore, minimizing the bioactivation potential of lead structures in the early phases of drug discovery by a modification to low-risk drug molecules is a priority for the pharmaceutical companies. Additionally, excellent potency and pharmacokinetic (PK) behaviour help in ensuring that appropriate (low dose) candidate drugs progress into the development phase. The current review discusses about RMs in the anticonvulsant drugs along with their mechanism vis-a-vis research efforts that have been taken to minimize the toxic effects of AEDs therapy.

The effectiveness of anti-inflammatory and anti-seizure medication for individuals with single enhancing lesion neurocysticercosis: A meta-analysis and expert group-based consensus recommendations

Single brain enhancing lesions (SEL) are the most common presentation of neurocysticercosis (NCC) observed on neuroimaging in people presenting with epileptic seizures not only on the Indian sub-continent and in travelers returning from cysticercosis-endemic regions, but are also present in other parts of the world. The aim of this study, which consisted of a systematic review (CRD42019087665), a meta-analysis and an expert group consultation, was to reach consensus on the best anti-seizure medication and anti-inflammatory treatment for individuals with SEL NCC. Standard literature review methods were used. The Cochrane risk of bias tool was used and random effects model meta-analyses were performed. The quality of the body of evidence was rated using GRADE tables. The expert committee included 12 gender and geographically balanced members and recommendations were reached by applying the GRADE framework for guideline development. The 1-1.5-year cumulative incidence of seizure recurrence, cyst resolution or calcification following anti-seizure medication (ASM) withdrawal was not statistically different between ASM of 6, 12 or 24 months. In contrast, in persons whose cyst calcified post treatment, longer ASM decreased seizure recurrence. The cumulative incidence ratio (CIR) 1-1.5 years after stopping ASM was 1.79 95% CI: (1.00, 3.20) for patients given 6 versus 24 months treatment. Anti-inflammatory treatment with corticosteroids in patients treated with ASM compared to patients treated with ASM only showed a statistically significant beneficial effect on seizure reduction (CIR 0.44, 95% CI 0.23, 0.85) and cyst resolution (CIR 1.37, 95%CI: 1.07, 1.75). Our results indicate that ASM in patients with SEL NCC whose cysts resolved can be withdrawn, while patients whose cysts calcified seem to benefit from prolonged anti-seizure medication. Additional corticosteroid treatment was found to have a beneficial effect both on seizure reduction and cyst resolution.

The Roles of Immunoregulatory Networks in Severe Drug Hypersensitivity

The immunomodulatory effects of regulatory T cells (Tregs) and co-signaling receptors have gained much attention, as they help balance immunogenic and immunotolerant responses that may be disrupted in autoimmune and infectious diseases. Drug hypersensitivity has a myriad of manifestations, which ranges from the mild maculopapular exanthema to the severe Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome (DRESS/DIHS). While studies have identified high-risk human leukocyte antigen (HLA) allotypes, the presence of the HLA allotype at risk is not sufficient to elicit drug hypersensitivity. Recent studies have suggested that insufficient regulation by Tregs may play a role in severe hypersensitivity reactions. Furthermore, immune checkpoint inhibitors, such as anti-CTLA-4 or anti-PD-1, in cancer treatment also induce hypersensitivity reactions including SJS/TEN and DRESS/DIHS. Taken together, mechanisms involving both Tregs as well as coinhibitory and costimulatory receptors may be crucial in the pathogenesis of drug hypersensitivity. In this review, we summarize the currently implicated roles of co-signaling receptors and Tregs in delayed-type drug hypersensitivity in the hope of identifying potential pharmacologic targets.

Principles of Pharmacotherapy of Seizures and Status Epilepticus

Status epilepticus is a neurological emergency with an outcome that is highly associated with the initial pharmacotherapy management that must be administered in a timely fashion. Beyond first-line therapy of status epilepticus, treatment is not guided by robust evidence. Optimal pharmacotherapy selection for individual patients is essential in the management of seizures and status epilepticus with careful evaluation of pharmacokinetic and pharmacodynamic factors. With the addition of newer antiseizure agents to the market, understanding their role in the management of status epilepticus is critical. Etiology-guided therapy should be considered in certain patients with drug-induced seizures, alcohol withdrawal, or autoimmune encephalitis. Some patient populations warrant special consideration, such as pediatric, pregnant, elderly, and the critically ill. Seizure prophylaxis is indicated in select patients with acute neurological injury and should be limited to the acute postinjury period.

A Ten-Year-Old Boy with Antiepileptic Drugs-Induced DRESS Syndrome

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a life-threatening adverse drug reaction if it is not timely diagnosed and treated. This happens probably following a cascade of immune reactions after the administration of the drug ultimately leading to multiorgan failure and death. Several groups of drugs have been identified as potential aetiologies but the commonest one identified is antiepileptic drugs. The clinical features of DRESS syndrome usually appear several weeks after commencing the offending drug. Initially, fever lymphadenopathy and rash appear followed by hepatitis. Rash is the most prominent feature, and it is a generalized erythematous nonblanching maculopapular rash without the involvement of the mucus membranes or eyes. The rash desquamated over the following days and changed it's context to an exfoliative dermatitis. We report a case of a 10-year-old boy who is one of the twins born to nonconsanguineous parents at 34 weeks of gestation.

Valproate-induced Drug Rash Eosinophilia with Systemic Symptoms Syndrome: An Unknown Hepatotoxicity

Drug rash eosinophilia with systemic symptoms (DRESS syndrome) presents as an acute febrile illness with leukocytosis, eosinophilia, lymphadenopathy, skin rash with acute hepatitis, renal failure, myositis, or systemic organ involvement. Aromatic anticonvulsants like phenytoin, carbamazepine, and phenobarbital cause drug-induced hypersensitivity or DRESS syndrome. However, sodium valproate being nonaromatic compound although known hepatotoxic drug in preexisting chronic liver disease has never been reported to cause DRESS syndrome alone. Here we report an interesting case of DRESS syndrome caused by valproate, which presented as an acute hepatitis illness with rash, renal dysfunction, and typical hematological features of DRESS syndrome within 2 months of the introduction of the drug in an epileptic patient. Patient initially showed a good response to intravenous steroids with improvement in the liver and renal dysfunction. However, later on, developed pancytopenia either due to steroid-induced sepsis or DRESS syndrome-related secondary hemophagocytosis (HPS) due to involvement of bone marrow as a rare occurrence and succumbed to illness.

How to cite this article

Gupta T. Valproate-induced Drug Rash Eosinophilia with Systemic Symptoms Syndrome: An Unknown Hepatotoxicity. Euroasian J Hepato-Gastroenterol 2019;9(2):102-103.

Managing the patient with epilepsy and renal impairment

PURPOSE

Epilepsy affects more than 50 million people worldwide and its management can be complicated by comorbidities such as impaired renal function. To optimize epilepsy control in patients with kidney disease, clinicians need to be aware of how antiepileptic drugs (AEDs) are affected by impaired renal function and how the kidneys are affected by epilepsy management strategies. Herein we present a narrative review with systematic literature search to discuss the use of AEDs in patients with renal impairment, including those undergoing dialysis, as well as the nephrotoxic effects of some AEDs. We finally conclude the article by providing practical tips about our approach to using AEDs in the setting of renal disease.

METHODS

A literature search targeting epilepsy management in patients with kidney disease was performed in MEDLINE database (1946 to 7th Jan 2019).

RESULTS

A total of 1193 articles were found. After duplicate removal, title and abstract screening followed by full text screening, a total of 110 references were included in this review. Additional information was included from drug product monographs.

CONCLUSION

The disposition of AEDs can be altered in patients with impaired renal function, leading to a higher risk of AED toxicity or therapy failure. Renal dosage adjustment and close monitoring is recommended. Although AED-induced nephrotoxicity is rare, it is unpredictable and clinicians need to vigilant about this possibility. In addition, AEDs renal adverse reactions and renal drug interactions should be considered when selecting an AED.

An Epileptic Patient with Recurrent Hyperbilirubinemia Caused by Gilbert Syndrome

Gilbert syndrome (GS) is characterized by intermittent indirect bilirubin elevation. Several antiepileptic drugs (AEDs) impair the liver function to different degrees, such as valproic acid, lamotrigine, phenobarbital, phenytoin, and carbamazepine. Herein, we present the case of a 26-year-old epileptic patient with frequently recurring mild hyperbilirubinemia during taking AEDs. After repeated adjustment of the doses and types of AEDs, the bilirubin level still remained elevated. He was then referred to the Gastroenterology Department. The results of diagnostic tests, clinical manifestation, imaging studies, liver biopsy and whole-exome sequencing all made contributions to our conclusion that GS played an important role in the elevation of bilirubin. Ultimately, his seizure was controlled by levetiracetam (500 mg per day) and he was advised to periodically undergo the liver function tests.

Suspected phenobarbital-induced fever in a cat

CASE SUMMARY

A 3-year-old spayed female domestic shorthair cat developed a fever 1 week after starting the anticonvulsant phenobarbital. A diagnostic work-up for seizures and subsequent onset of fever of unknown origin, consisting of MRI of the brain, cerebrospinal fluid analysis and infectious disease testing, was unremarkable. The cat was switched from phenobarbital onto pregabalin with complete resolution of the fever within 24 h, consistent with a drug-induced fever following phenobarbital administration.

RELEVANCE AND NOVEL INFORMATION

While anticonvulsant hypersensitivities have been reported and studied in veterinary medicine, phenobarbital-induced fever outside of the context of systemic clinical signs has not been documented in the veterinary scientific literature. Drug-induced fever secondary to anticonvulsants should be considered in patients that develop a fever after starting anticonvulsant therapy with an unrewarding diagnostic work-up for fever of unknown origin.

Drug Reaction with Eosinophilia and Systemic Symptoms: An Update and Review of Recent Literature

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, is also known as drug induced hypersensitivity syndrome and by various other names. It is now recognised as one of the severe cutaneous adverse reaction (SCAR) and can be potentially life-threatening. Historically, it was most frequently linked with phenytoin and was initially described as phenytoin hypersensitivity syndrome. However, it was later found to be caused by various other medications. Anticonvulsants and sulfonamides are the most common offender. Characteristically DRESS has a latent period of 2 to 6 weeks. The pathophysiology remains incompletely understood but involves reactivation of viruses and activation of lymphocyte. It is manifested most commonly with a morbilliform cutaneous eruption with fever and lymphadenopathy. The severity of this syndrome is related to the systemic involvement, which can result in multi-organ failure. Most important step in the management of DRESS is early diagnosis and immediate cessation of the suspected offending drug. Patients of DRESS syndrome should be managed in an intensive care set up for appropriate supportive care and infection control. Topical corticosteroids can give symptomatic relief, but systemic therapy with steroid and other immunosuppressant is usually required.

Risk factors of early adverse drug reactions with phenytoin: A prospective inpatient cohort

INTRODUCTION

Phenytoin (PHT) is an effective and inexpensive antiepileptic drug (AED). However, its use has been limited for fear of adverse drug reactions (ADRs) and is being replaced by newer AED, increasing the costs and causing major budget problems, particularly for developing countries.

OBJECTIVE

The objective of this study was to determine ADR frequency, explore, and establish related risk factors.

METHODS

Prospective data were collected from a cohort of inpatients using PHT for the first time. Pharmacovigilance was performed during hospitalization and after one month from the discharge. Clinical variables, plasma levels, and concomitant medications were collected and their association with the occurrence of different ADRs was explored.

RESULTS

One hundred patients were included: 59 were women, and mean age was 59±21years. Thirty-three patients presented ADR, all moderate and idiosyncratic. The most frequent were rash (17%), fever (10%), and elevated transaminases (10%). Female gender (85% vs 52%, p=0.029), younger age (mean age: 49 vs 62years, p=0.032), and higher PHT plasmatic levels after IV-PO load (mean plasmatic levels: 18.6 vs 13.9μg/mL, p=0.040) were found to be associated with rash. A higher number of concomitant medications were also found to be associated with the risk for developing any ADR. The multivariate analysis revealed an association between rash and younger age (cut-off: 35years old; relative risk (RR)=11.7; p=0.026), and higher PHT plasmatic levels (cut-off: 16μg/mL; RR=12.5; p=0.021); and increased risk of elevated transaminases with use of PHT inductors (RR=18; p=0.006). A longer hospital stay was found in patients who developed fever (mean: 43days, p<0.0001) and elevated transaminases (mean: 26days, p=0.041) compared with patients without ADR (mean: 17days).

CONCLUSIONS

Phenytoin is a widely used AED associated with easily detectable ADR through structured pharmacovigilance. The development of ADR is associated with longer hospital stays. Recognition of local risk factors may lead to ADR prevention in a near future. Larger studies are needed to better define PHT-related ADR risk profile and to individualize treatment regimens.

Drug rash with eosinophilia and systemic symptoms (DRESS) caused by phenytoin

Drug rash with eosinophilia and systemic symptoms (DRESS) is a rare but potentially life-threatening condition with high mortality. Diagnosis is challenging due to variable clinical presentation and a protracted latency period following initiation of the offending drug. DRESS is a complex interplay that starts by introduction of the offending drug, reactivation of viruses and activation of the immune system. Herpes virus reactivation is considered a diagnostic marker and indicator of illness severity. Prompt recognition and the removal of offending agent remain the key to successful treatment. In cases of severe organ involvement, corticosteroids, immunoglobulins, antiviral and specialist consultation may be helpful. Here we present a case of a 36-year-old African-American male who presented with symptoms mimicking sepsis with an associated skin eruption that was diagnosed as DRESS.

Drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome: clinical features of 27 patients

BACKGROUND

Drug reaction with eosinophilia and systemic symptoms (DRESS) [also called drug-induced hypersensitivity syndrome (DIHS)] includes severe reactions to drugs that need to be promptly recognized by physicians.

AIM

To explore heterogeneity in the clinical presentation of DRESS/DIHS at a large academic hospital in Latin America, using the criteria defined by the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) scoring system.

METHODS

A retrospective medical record review of 60 patients with diagnostic suspicion of DRESS/DIHS admitted to our hospital between July 2008 and April 2012 was performed, including demographic data, clinical features, laboratory findings and treatment.

RESULTS

Of the 60 patients, 27 fulfilled the criteria for DRESS/DIHS. Maculopapular exanthema (85.1%), fever (96.2%) and hepatic involvement (85.1%) were the most common features. Anticonvulsants were the most common causal drugs (77.7%); Phenytoin was the most common individual drug (44.4%), followed by carbamazepine (29.6%). All patients were treated initially with prednisone 1 mg/kg/day. Mortality rate was 4%.

CONCLUSION

The major findings of this study (to our knowledge the largest collection of data on DRESS/DIHS in Latin America) include a positive statistical association between presence of atypical lymphocytes and higher levels of alanine aminotransferase (P < 0.001) and reinforce the importance of anticonvulsants in the pathogenesis of this severe reaction.

Comorbidity of Stevens-Johnson syndrome and neutropenia associated with lamotrigine: a case report

A 19-year-old woman with a medical history of depressive mood arrived and was treated with lamotrigine at 25 mg/day. On day 10, a high fever of 39.3 °C and a diffuse, erythematous, pruritic full-body rash involving the palms of her hands and the soles of her feet developed, and she was diagnosed with Stevens-Johnson syndrome (SJS). On day 17, white blood cell count (WBC) result was 1,240/μl with 54.1% neutrophils (670/μl), and the WBC decreased to 840/μl with 60.7% neutrophils (510/μl) on day 18. The trend toward improvement included skin symptoms after steroid pulse therapy using 1000 mg/day. Based on the clinical course, we concluded that the SJS and leukopenia and/or neutropenia are associated with lamotrigine. Monitoring of WBC should be kept in mind when administering lamotrigine.

[Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): a review]

DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms), also known as hypersensitivity syndrome (HSS), is a severe and potentially life-threatening drug reaction. The worldwide rate of mortality is about 10 %, its incidence is increasing. Drugs that most frequently induce DRESS are aromatic anticonvulsive drugs (carbamazepine, lamotrigine, phenobarbital), and more recently new retroviral therapies. The pathogenesis of DRESS is not yet fully understood, but is certainly multifactorial involving a combination of immune reactions, ethnic predisposition, genetically determined enzyme deficiencies and reactivation of herpes viruses (HHV-6, HHV-7, EBV, CMV). Because of the involvement of the skin and internal organs, the clinical picture can be very variable. No specific clinical, histologic or laboratory parameter is available, so the diagnosis has to rely on the clinical appearance. The long latency period between start of drug intake and the initial manifestation of DRESS and the successive onset of skin and organ involvement complicates the early diagnosis. Although or even because DRESS represents a diagnostic challenge, detailed knowledge about this disease is of utmost importance to enable early therapeutic actions.

Single centre 20 year survey of antiepileptic drug-induced hypersensitivity reactions

BACKGROUND

Epilepsy is a chronic neurological disease which affects about 1% of the human population. There are 50 million patients in the world suffering from this disease and 2 million new cases per year are observed. The necessary treatment with antiepileptic drugs (AEDs) increases the risk of adverse reactions. In case of 15% of people receiving AEDs, cutaneous reactions, like maculopapular or erythematous pruritic rash, may appear within four weeks of initiating therapy with AEDs.

METHODS

This study involved 300 epileptic patients in the period between September 1989 and September 2009. A cutaneous adverse reaction was defined as a diffuse rash, which had no other obvious reason than a drug effect, and resulted in contacting a physician.

RESULTS

Among 300 epileptic patients of Neurological Practice in Kielce (132 males and 168 females), a skin reaction to at least one AED was found in 30 patients. As much as 95% of the reactions occurred during therapies with carbamazepine, phenytoin, lamotrigine or oxcarbazepine. One of the patients developed Stevens-Johnson syndrome.

CONCLUSION

Some hypersensitivity problems of epileptic patients were obviously related to antiepileptic treatment. Among AEDs, gabapentin, topiramate, levetiracetam, vigabatrin, and phenobarbital were not associated with skin lesions, although the number of patients in the case of the latter was small.

A review of cutaneous drug eruptions

Cutaneous drug eruptions can range from an asymptomatic rash to a life-threatening emergency. Because of the high frequency, morbidity, and potential mortality associated with drug eruptions, patients with possible drug reactions should promptly be recognized, worked up, and treated. Drug reactions are common in the elderly population due to age-related alterations in metabolism, excretion of medications, and polypharmacy. This review discusses the epidemiology, pathogenesis, clinical presentation, diagnosis, and management of drug eruptions that providers commonly encounter in the care of the geriatric population. An algorithm for an approach to patients with a suspected drug eruption is presented.

Adverse drug reactions induced by valproic acid

Valproic acid is a widely-used first-generation antiepileptic drug, prescribed predominantly in epilepsy and psychiatric disorders. VPA has good efficacy and pharmacoeconomic profiles, as well as a relatively favorable safety profile. However, adverse drug reactions have been reported in relation with valproic acid use, either as monotherapy or polytherapy with other antiepileptic drugs or antipsychotic drugs. This systematic review discusses valproic acid adverse drug reactions, in terms of hepatotoxicity, mitochondrial toxicity, hyperammonemic encephalopathy, hypersensitivity syndrome reactions, neurological toxicity, metabolic and endocrine adverse events, and teratogenicity.

Hepatic necrosis associated with drug-induced hypersensitivity syndrome

Drug-induced hypersensitivity syndrome (DIHS; also known as drug reaction with eosinophilia and systemic symptoms [DRESS]) is a life-threatening condition first described by Chaiken et al. in 1950. It is characterized by extensive mucocutaneous rash; fever; lymphadenopathy; hepatitis; hematological abnormalities; damage to several organs such as kidney, heart, lungs, and pancreas; and possible reactivation of human herpesvirus-6 (HHV-6) or other herpes virus. Rare and severe cases may present hepatic necrosis, and about 15% of them result in death or liver transplantation. A hallmark of this syndrome is the late onset of symptoms after the drug exposure. The most common culprit drugs are the aromatic anticonvulsants (in almost 30% of the cases) and the antibiotics (which in some series represent 20% of the cases). The authors report a case of a 41-year-old female who presented to the emergency department with erythroderma, acute hepatitis, acute pancreatitis and acute renal failure, and was then treated with corticosteroid after the diagnosis of DIHS/DRESS. A specific culprit drug could not confidently be determined due to the presence of multiple drugs used by the patient. The clinical and laboratory outcome was apparently satisfactory, but unexpectedly, on the sixth day of hospitalization, the patient complained of nonspecific malaise, drowsiness, which progressed in a few hours with signs and symptoms of hepatic failure, refractory shock, and death. The autopsy findings showed submassive hepatic necrosis, and the immediate cause of death was attributed to hepatic failure.

Allopurinol-induced DRESS syndrome

A 70-year-old man was admitted to our clinic with complaints of fever, jaundice, dyspnea, and generalized rash after 3 months of allopurinol treatment for gout. On physical examination, he was found to have fever (38.5°C), jaundice, and generalized maculopapular rash. Leukocytosis, eosinophilia, elevation of liver enzymes, and hyperbilirubinemia were detected in his blood analysis. Skin biopsy was consistent with drug-induced hypersensitivity. He was diagnosed as Drug Rash with Eosinophilia and Systemic Symptoms (DRESS). Allopurinol treatment was stopped and steroid treatment was launched. At day 24 of admission, the patient died because of multiple organ failure.

Drug reaction with Eosinophilia and Systemic Symptoms (DRESS) / Drug-induced Hypersensitivity Syndrome (DIHS): a review of current concepts

The Drug Reaction with Eosinophilia and Systemic Symptoms syndrome, also known as Drug Induced Hypersensitivity Syndrome presents clinically as an extensive mucocutaneous rash, accompanied by fever, lymphadenopathy, hepatitis, hematologic abnormalities with eosinophilia and atypical lymphocytes, and may involve other organs with eosinophilic infiltration, causing damage to several systems, especially to the kidneys, heart, lungs, and pancreas. Recognition of this syndrome is of paramount importance, since the mortality rate is about 10% to 20%, and a specific therapy may be necessary. The pathogenesis is related to specific drugs, especially the aromatic anticonvulsants, altered immune response, sequential reactivation of herpes virus and association with HLA alleles. Early recognition of the syndrome and withdrawal of the offending drug are the most important and essential steps in the treatment of affected patients. Corticosteroids are the basis of the treatment of the syndrome, which may be associated with intravenous immunoglobulin and, in selected cases, Ganciclovir. The article reviews the current concepts involving this important manifestation of adverse drug reaction.

Procalcitonin, a high acute phase reactant in antiepileptic hypersentivity syndrome in pediatric age

Antiepileptic hypersensitivity syndrome (AHS) is a potentially life-threatening syndrome in pediatric cases. It is associated with aromatic anticonvulsivant drugs and others antibiotics with or without associated reactivation of virus. The pathogenesis of the process is not clear. Clinical feature of this syndrome include cutaneous reactions, fever and lymphadenopathies, but different organs can be involved. In laboratory analyses we can find leucocytosis, eosinophilia, and increase in transaminase levels. Significant elevation of procalcitonin (PCT) has been described in two adults patients. This study we report two cases of a 14-year-old male and a 13-year-old female with a AHS and a high level of the PCT. These are the first cases described in pediatric age. Establishing a diagnosis of AHS is important to avoid the use of the involved drug. The treatment is based on the withdrawal of the drugs that are supposed and if there is no improvement or a deterioration of the patient, the use of systemic corticosteroids is often useful.

Acute hypersensitivity syndrome caused by valproic Acid: a review of the literature and a case report

Valproic acid (VPA) is an antiepileptic medication used in the treatment of bipolar disorder. Its toxicity profile is characterized by a very rare but well-documented complication-hepatotoxicity. The risk of acute hypersensitivity syndrome (AHS) caused by VPA is less well known. In the vast majority of reported cases of AHS, the syndrome is the result of aromatic anticonvulsants (AAs), such as carbamazepine or phenytoin. These compounds also have in-class cross-reactivity. We present the case of a 25-year-old woman with bipolar disorder who was unable to tolerate aripiprazole, ziprasidone, and lamotrigine. She was given extended-release VPA as a trial and developed AHS with a generalized rash, fever, liver and kidney involvement, and eosinophilia one week after the initiation of treatment. She recovered after one month of treatment, which included ten days of hospitalization. Our review of the literature focuses on AA and non-AA medications causing AHS.

Amlodipine-induced toxic epidermal necrolysis

The objective of this study is to report a case of amlodipine-induced dermatotoxicity following treatment for diabetic nephropathy. Although other members of the dihydropyridine calcium channel blockers have been reported to cause dermatotoxic reactions, this is the first report attributing this effect to amlodipine. A 71-year-old diabetic and hypertensive woman had been noted to have worsened renal dysfunction and hyperkalemia attributed to enalapril, thus a trial of amlodipine was begun. On day 12 of amlodipine therapy, the patient developed a pruritic maculopapular rash on her hands for which she sought medical attention. On day 16, she presented again to the emergency department now with hives and small blisters involving the trunk and arms with ∼25% TBSA involvement warranting transfer to a regional burn treatment center. The rash progressed after admission to 48.5% TBSA and included conjunctival sloughing. The patient's hospital course was uneventful, and she was discharged after 8 days. Drug-induced dermatotoxicity presenting as toxic epidermal necrolysis is often caused by antibiotics and antiepileptic medications; however, calcium channel blockers are an uncommon cause. The Naranjo assessment yielded a score of 5, and the SCORTEN was 4 with a predicted mortality of 58%. This report represents the first published case of amlodipine-induced toxic epidermal necrolysis.

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 Art of Managing Conversions between Antiepileptic Drugs: Maximizing Patient Tolerability and Quality of Life

Conversion between anti-epilectic drugs (AEDs) is frequently necessary in epilepsy care, exposing patients to a risk of incurring adverse effects and reduced quality of life. Little practical guidance is available to practitioners to guide conversions between AED monotherapies, or in adding a new adjunctive AED into a polytherapy regimen. This article reviews the impact of adverse effects of AEDs on quality of life in epilepsy patients, then reviews several important patient-related factors such as age, gender, medical and psychiatric co-morbidities, and co-medications that must be considered when selecting AEDs and ensuring tolerable and safe AED conversions. Practical strategies for transitional polytherapy AED conversion are then considered in different commonly encountered clinical scenarios in newly diagnosed and refractory epilepsy care, including inadequate seizure control, intolerable adverse effects, or idiosyncratic safety hazards. Successful conversion between AEDs requires regular monitoring for patient-reported adverse effects and appropriately reactive adjustment of AED therapy to maximize patient quality of life.

Anticonvulsant hypersensitivity syndrome treated with intravenous immunoglobulin

Anticonvulsant hypersensitivity syndrome is a severe, potentially life-threatening, reaction to the aromatic anticonvulsant medications. Reported here is a case of anticonvulsant hypersensitivity syndrome secondary to phenobarbital in a 2-year-old boy; he responded to drug withdrawal, corticosteroids, and intravenous immunoglobulin. The literature regarding treatment of this syndrome is reviewed.

Is the drug-induced hypersensitivity syndrome (DIHS) due to human herpesvirus 6 infection or to allergy-mediated viral reactivation? Report of a case and literature review

Background

Drug-Induced Hypersensitivity Syndrome (DIHS) is a severe and rare systemic reaction triggered by a drug (usually an antiepileptic drug). We present a case of DISH and we review studies on the clinical features and treatment of DIHS, and on its pathogenesis in which two elements (Herpesvirus infection and the drug) interact with the immune system to trigger such a syndrome that can lead to death in about 20% of cases.

Case presentation

We report the case of a 26-year old woman with fever, systemic maculopapular rash, lymphadenopathy, hepatitis and eosinophilic leukocytosis. She had been treated with antibiotics that gave no benefit. She was taking escitalopram and lamotrigine for a bipolar disease 30 days before fever onset. Because the patient's general condition deteriorated, betamethasone and acyclovir were started. This treatment resulted in a mild improvement of symptoms. Steroids were rapidly tapered and this was followed with a relapse of fever and a worsening of laboratory parameters. Human herpesvirus 6 (HHV-6) DNA was positive as shown by PCR. Drug-Induced Hypersensitivity Syndrome (DIHS) was diagnosed. Symptoms regressed on prednisone (at a dose of 50 mg/die) that was tapered very slowly. The patient recovered completely.

Conclusions

The search for rare causes of fever led to complete resolution of a very difficult case. As DIHS is a rare disease the most relevant issue is to suspect and include it in differential diagnosis of fevers of unknown origin. Once diagnosed, the therapy is easy (steroidal administration) and often successful. However our case strongly confirms that attention should be paid on the steroidal tapering that should be very slow to avoid a relapse.

Genetic predisposition of life-threatening antiepileptic-induced skin reactions

IMPORTANCE OF THE FIELD

Recent advances in pharmacogenetic studies have uncovered increasingly more genes that predispose individuals to adverse drug reactions. Aromatic antiepileptic drugs (AEDs) are a frequent cause of severe cutaneous adverse reactions (SCAR). A strong genetic association between HLA-B*1502 and carbamazepine (CBZ)-induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) has been shown in Han Chinese patients.

AREAS COVERED IN THIS REVIEW

This article reviews and updates genetic information associated with CBZ and other AEDs causing SCAR in different ethnic populations.

WHAT THE READER WILL GAIN

Independent studies from different countries confirmed that patients carrying the HLA-B*1502 are at high risk of SJS/TEN when exposed to CBZ. The US FDA and similar regulatory agencies in Canada and Taiwan have updated the CBZ drug label to include the genetic information. Available data also suggest that HLA-B*1502 is a risk allele for SJS/TEN caused by other aromatic AEDs with a similar structure to CBZ.

TAKE HOME MESSAGE

Screening for HLA-B*1502 allele before starting treatment with CBZ is justified in patients from high-risk populations as recommended by regulatory agencies. Similar chemicals should also be avoided in individuals who test positive for HLA-B*1502.

Immune mediation of hypersensitivity adverse drug reactions: implications for therapy

Adverse drug reactions are among the top causes of death in the developed world, and among the spectrum of adverse drug reactions, drug hypersensitivity is a principal contributor to serious adverse drug events. The pathophysiology of drug hypersensitivity remains incompletely understood, but seems to involve the initial recognition of a drug or metabolite by the immune system followed by an immune response that determines the clinical manifestations. At present, there are two competing theories for how immune recognition occurs: the Hapten Hypothesis in which drug hapten-carrier association is the key driver for immune recognition and the Pharmacological Interference Concept that postulates direct recognition of drugs by low affinity association with the T cell receptor. The Danger Hypothesis provides a potentially important addition to the Hapten Hypothesis. Therapy for drug hypersensitivity has traditionally involved excellent supportive care. Although corticosteroids and intravenous immunoglobulin have both been used as immunomodulatory therapy, there is no robust evidence supporting the efficacy of their therapy for drug hypersensitivity. Recent advances in molecular biology and genomic pharmacology offer previously unappreciated opportunities to clarify the controversies surrounding drug hypersensitivity and to better diagnose, treat and, it is hoped, prevent drug hypersensitivity in the future.

Acute kidney injury caused by zonisamide-induced hypersensitivity syndrome

Drug rash with eosinophilia and systemic symptoms (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS), is a severe adverse drug reaction affecting multiple organs caused by drug treatment. The current report describes a man who was prescribed zonisamide for epilepsy and subsequently developed widespread skin rash, acute kidney injury, high-grade fever, eosinophilia, liver dysfunction, lymphadenopathy and an increase in antihuman herpesvirus-6 immunoglobulin G titer. Hypersensitivity to zonisamide was confirmed by the skin patch test. Based on these findings, the patient was diagnosed with DRESS/DIHS caused by zonisamide. This is the first report of acute kidney injury due to zonisamide-induced DRESS/DIHS.

Hyperchloremic metabolic acidosis due to deferasirox in a patient with beta thalassemia major

OBJECTIVE

To report a case of hyperchloremic metabolic acidosis in a patient with beta thalassemia major secondary to treatment with deferasirox due to iron overload.

CASE SUMMARY

A 58-year-old white female with beta thalassemia major was admitted with fever, fatigue, abnormal liver function test results, and hyperchloremic metabolic acidosis (lactate dehydrogenase 494 U/L, aspartate aminotransferase 167 U/L, alanine aminotransferase 250 U/L, gamma-glutamyl transferase 102 U/L, total bilirubin 3.79 mg/dL, direct bilrubin 2.37, potassium 3.3 mEq/L, PO(2) 81.4 mm Hg, PCO(2) 29.4 mm Hg, HCO(3) 16 mEq/L, pH 7.35, chloride 116 mEq/L, anion gap 7.5 mEq/L). Twenty-five days before admission the patient decided to discontinue treatment with deferoxamine for chronic iron overload and continue treatment with oral deferasirox 1500 mg/day. Despite extended clinical and laboratory examination, no obvious cause of fever, hepatitis, or hyperchloremic metabolic acidosis was revealed. Diagnosis was compatible with tubular dysfunction, drug-induced hepatitis, and hypersensitivity reaction due to deferasirox. All pathological findings were fully reversible and our patient had an excellent outcome.

DISCUSSION

The presence of tubular dysfunction should be considered in any patient with otherwise unexplained hyperchloremic metabolic acidosis. In our patient, other potential causes of metabolic hyperchloremic acidosis were ruled out. Toxic effects of deferasirox are probably caused by chelation of mitochondrial iron, leading to adenosine triphosphate depletion in tubular epithelial cells. Use of the Naranjo probability scale revealed that the adverse reaction was probable.

CONCLUSIONS

Kidney toxicity may be a major issue in the management of patients receiving deferasirox. Our case indicates a potential risk of renal toxicity with the presence of tubular dysfunction and hyperchloremic metabolic acidosis in patients undergoing treatment with deferasirox.

[Anticonvulsant hypersensitivity syndrome: an entity to be remembered]

Anticonvulsant hypersensitivity syndrome is an unpredictable, potentially fatal drug reaction to aromatic anticonvulsants such as carbamazepine, phenytoin and phenobarbital. The hallmark features include fever, eosinophilia, rash and involvement of one or more internal organs. Clearly established diagnostic criteria and treatment guidelines are lacking. A high index of suspicion is required to identify this syndrome, allowing early withdrawal of the drug and avoiding re-exposure. We report an illustrative case of anticonvulsant hypersensitivity syndrome and review the published literature.