Medication use and the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis

Immunological principles of adverse drug reactions: the initiation and propagation of immune responses elicited by drug treatment

Adverse drug reactions account for between 2 to 5% of all hospital admissions and can prevent the administration of an otherwise effective therapeutic agent. Hypersensitivity or immune-mediated reactions, although less common, tend to be proportionately more serious. There is convincing evidence to implicate the immune system in the pathogenesis of hypersensitivity reactions. Our understanding of the way in which the immune system recognises drugs is based on the hapten hypothesis; the onset of hypersensitivity involves drug bioactivation, covalent binding to proteins, followed by uptake, antigen processing and T cell proliferation. Central to this hypothesis is the critical role of drug metabolism, with the balance between metabolic bioactivation and detoxification being one important component of individual susceptibility. The purpose of this review is to classify drug hypersensitivity reactions in terms of their clinical presentation, and also to consider recent advances in our understanding of the chemical, biochemical and, in particular, cellular immunological mechanisms of hypersensitivity. The following topics are reviewed: (i) drug disposition and cellular metabolism; (ii) mechanisms of antigen processing and presentation; (iii) the role of cytokines and co-stimulatory molecules in the induction and maintenance of a polarised immune response; and (iv) the application of the hapten hypothesis, danger hypothesis and serial triggering model to drug hypersensitivity. A greater understanding of the mechanism(s) of hypersensitivity may identify novel therapeutic strategies and help to combat one of the more severe forms of adverse reactions to drugs.

Advances in molecular toxicology-towards understanding idiosyncratic drug toxicity

Idiosyncratic drug toxicity is a major complication of drug therapy and drug development. Such adverse drug reactions (ADRs) include anaphylaxis, blood dyscrasias, hepatotoxicity and severe cutaneous reactions. They are usually serious and can be fatal. At present, prediction of idiosyncratic ADRs at the preclinical stage of drug development is not possible because there are no suitable animal models and we do not understand the basic mechanisms involved in the toxicity when it does occur in man. Many idiosyncratic reactions appear to have an immunological aetiology. For example, there is increasing evidence for the role of T lymphocytes in severe skin reactions. Nevertheless, the sequence of events by which a simple chemical can elicit severe tissue damage remains poorly understood and alternative novel mechanisms of toxicity must also be explored. The purpose of this article will be to review the currently accepted mechanisms of idiosyncratic drug toxicity at the chemical and the molecular levels. In particular, we will consider how recent advances in cellular immunology and molecular biology can improve our understanding of both the chemical and clinical aspects of drug hypersensitivity. Recent advances in the role of both inter- and intra-cellular signalling in the regulation of the immune response to drugs and their metabolites will be discussed. The long-term aim of such research is to provide test systems for the evaluation of drug safety and patient susceptibility to idiosyncratic drug toxicity.

Idiosyncratic drug reactions: the reactive metabolite syndromes

Idiosyncratic drug reactions are unpredictable reactions that can result in significant morbidity and mortality. Severe reactions are often characterised by fever and internal organ involvement. Despite progress in the identification of reactive metabolites believed to be the cause of idiosyncratic reactions, the basic mechanisms remain elusive. Furthermore, because of the lack of consensus regarding definition of these syndromes, reporting, and therefore epidemiological data, are often unreliable. Research is needed to explore further the pathophysiology of these reactions, so that better diagnostic tests and treatment methods can be developed.

Drug-induced Stevens-Johnson syndrome/toxic epidermal necrolysis

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a rare (occurring in approximately 2 to 3 people/million population/year in Europe and the US), life-threatening, intolerance reaction of the skin. It is most often caused by drugs (most commonly sulfonamides, nonsteroidal anti-inflammatory drugs, antimalarials, anticonvulsants, and allopurinol). SJS/TEN is characterized by a macular exanthema ('atypical targets') which focusses on the face, neck, and the central trunk regions. Lesions show rapid confluence, a positive Nikolsky's sign, and quickly result in widespread detachment of the epidermis and erosions. Mucosal, conjunctival, and anogenital mucous membranes are prominently involved. Histopathology shows satellite cell necrosis in the early stages progressing to full thickness necrosis of the epidermis, contrasting with rather inconspicuous inflammatory infiltrates of the dermis. Damage to the skin is thought to be mediated by cytotoxic T lymphocytes and mononuclear cells which induce apoptosis in keratinocytes expressing drug-derived antigens at their surfaces. No guidelines for the treatment of SJS/TEN exist since no controlled clinical trials have ever been performed. The controversy over whether systemic corticosteroids should be used to curtail progression is still unresolved; while many authors agree that corticosteroids do in fact suppress progression, it is obvious that they also greatly enhance the risk of infection, the complication which most frequently leads to a fatal outcome. It appears reasonable to only administer corticosteroids in the phase of progression and to withdraw them as soon as possible, and to add antibacterials for prophylaxis. Recently, in a small series of patients, intravenous immunoglobulins were presumed to be effective by the blockade of lytic Fas ligand-mediated apoptosis in SJS/TEN. However, these results have to be confirmed by large clinical trials. Supportive treatment and monitoring of vital functions is of utmost importance in SJS/TEN, and out-patient treatment is unacceptable. Recovery is usually slow, depending on the extent and severity and the presence of complications, and may take 3 to 6 weeks. Skin lesions heal without scars as a rule, but scarring of mucosal sites is a frequent late complication, potentially leading to blindness, obliteration of the fornices and anogenital strictures. There is no reliable laboratory test to determine the offending drug; diagnosis rests on the patient's history and the empirical risk of drugs to elicit skin SJS/TEN. Provocation tests are not indicated since re-exposure is likely to elicit a new episode of SJS/TEN of increased severity.

Management of toxic epidermal necrolysis

Toxic epidermal necrolysis and Stevens-Johnson syndrome are rare, life-threatening drug reactions. Widespread epidermal necrosis and mucosal erosions lead to complications similar to those developing after extensive burns. Treatment is supportive. The role of steroids and other potential disease-modifying agents remains to be established by controlled studies.

Epidemiological assessment of drug-induced disease

Adverse reactions are a potential concern for physicians when they prescribe or recommend drugs. Epidemiological principles, when combined with clinical judgment, can be of help in this situation, starting with an appreciation of the strengths and weaknesses of different sources of information on adverse reactions--clinical trials, case reports, and formal epidemiological studies. The latter studies generally provide the most comprehensive information on the risks of serious adverse drug reactions. An understanding of the different types of risk estimates, relative and absolute, is also needed--we stress the value of the absolute risk as the best measure of the impact of an adverse reaction. Rare serious reactions, although striking, have little impact on individual risk, whereas more common reactions, even with much lower fatality rates, are more likely to lead to adverse outcomes for patients. The importance of balancing risks and benefits, taking into account all the information about an individual patient's risk profile, is also highlighted.

Toxic epidermal necrolysis associated with treatment for preterm labor

We report a 29-year-old pregnant woman who developed toxic epidermal necrolysis at 29 weeks of gestation after administration of ritodrine, indomethacin and betamethasone. Toxic epidermal necrolysis is an unreported side effect of this widely used combination of medications. Since toxic epidermal necrolysis is a potentially fatal disease, awareness of a possible association is warranted.

Toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a rare but life-threatening adverse drug reaction. Implicated drugs are sulfonamides, anticonvulsants, allopurinol, and pyrazolone derivatives. Recently, advances in pathogenesis have been made in two directions. It is now known that (1) most patients with TEN have an abnormal metabolism to the culprit drug; and (2) the mechanism leading to epidermal necrolysis seems to be a cell-mediated cytotoxic reaction. The treatment remains symptomatic.

A case of toxic epidermal necrolysis-type drug eruption induced by oral lysozyme chloride

We report a case of toxic epidermal necrolysis-type drug eruption. A 23-year-old man took an oral over-the-counter preparation for the common cold. A few days later, generalized erythema developed with systemic malaise and pain. A multiple blister formation followed, and Nikolsky's sign was noted on each blister. A lymphocyte stimulation test (LST) with the patient's peripheral lymphocytes strongly suggested that the eruption was attributable to lysozyme chloride which was included in the preparation taken. Following an intravenous drip of betamethasone for two weeks, the eruptions improved favorably.

Anticonvulsant-induced toxic epidermal necrolysis: monitoring the immunologic response

BACKGROUND

Toxic epidermal necrolysis is a severe reaction with skin involvement induced by different drugs and other agents. The mechanisms implicated in the induction of the reaction are poorly understood.

OBJECTIVE

Our purpose was to study the involvement of T lymphocytes and other immunocompetent cells in the peripheral blood, blister fluid, and affected skin of 3 patients who had a severe reaction after receiving anticonvulsant medication.

METHODS

Quantification of T lymphocytes expressing the skin-homing receptor (cutaneous lymphocyte-associated antigen ¿CLA) in peripheral blood, skin, and skin blister fluid and assessment of other adhesion molecules, activation markers, and inflammatory interleukins by flow cytometry, immunohistochemistry, and reverse transcription-PCR.

RESULTS

An increase in CD3(+)CLA(+) cells paralleling the severity of the disease was observed in both peripheral blood and skin, tending to normalize as soon as patient's conditions improved. E-selectin was detected in endothelial vessels in parallel with CLA expression on lymphocytes. An overexpression of TNFalpha, IFN-gamma, and IL-2 was also observed in PBMCs. The expression of the different markers changed over the course of the disease.

CONCLUSIONS

These data show an increase in activated T cells expressing the skin-homing receptor in both tissue and peripheral blood accompanying clinical symptoms, with a recruitment of macrophages and an overexpression of cytokines. All these results suggest an important role for T cells in the production of toxic epidermal necrolysis.

Toxic epidermal necrolysis associated with acetaminophen ingestion

OBJECTIVE

To report a case of toxic epidermal necrolysis (TEN) associated with acetaminophen ingestion.

SUMMARY

A seven-year-old girl developed TEN after acetaminophen ingestion. The diagnosis was based on clinical evaluation and skin biopsy. A later acetaminophen challenge, undertaken by an allergist who questioned the diagnosis, resulted in a similar skin reaction.

DISCUSSION

TEN is a severe disease with a high mortality rate. TEN may be either idiopathic or associated with several clinical conditions, such as viral infections, autoimmune disorders, malignancy, and drug hypersensitivity. Because of the rarity of its association with acetaminophen, the diagnosis in our patient was questioned by an allergist who performed an oral acetaminophen rechallenge test despite the potential risk. This caused a severe skin reaction that required rehospitalization.

CONCLUSIONS

TEN can be caused by over-the-counter medications such as acetaminophen. Rechallenge with the causative drug carries a risk of severe complications and should be avoided.

Cutaneous reactions to drugs. An analysis of spontaneous reports in four Italian regions

AIMS

Cutaneous manifestations are frequently reported in association with drug use. The aim of this study was to analyse the skin reactions reported to the spontaneous surveillance systems of four Italian regions (Friuli Venezia Giulia, Lombardy, Sicily and the Veneto), and correlate the reports with estimated drug consumption during the same period, paying particular attention to the reactions to antimicrobial agents and nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

All of the adverse drug reactions (ADRs) reported spontaneously between January 1996 and December 1997 to the surveillance systems of four Italian regions (a total population of about 20 million people) were analysed by a panel of experts including dermatologists. On the basis of the Critical Term List of the World Health Organization (WHO), the reactions were classified as either serious or nonserious events. Drug consumption was expressed as a daily defined dose (DDD)/1000 inhabitants/day.

RESULTS

A total of 2224 adverse skin reaction reports (44.7% of all of the reported ADRs) were identified, making a reporting rate of about 5.5 per 100 000 inhabitants/year. The female/male ratio was 1.58, and the reporting rate progressively increased with age. The drug categories with the highest number of cutaneous reactions were antimicrobials, followed by NSAIDs, analgesics and radiology contrast media. There was a total of 372 (16.9%) serious reaction reports, the most frequent being angioedema (171 cases), erythema multiforme (68 cases) and photosensitivity (37 cases). Co-trimoxazole, followed by the cephalosporins and fluoroquinolones, were associated with the highest consumption-related reporting rate among the antimicrobials, and aspirin and dipyrone among the NSAIDs and analgesics.

CONCLUSIONS

Spontaneous reports from four Italian regions revealed that the skin was the organ most frequently affected by ADRs. The paper shows the validity of a regional decentralized system in Italy.

The diagnostic role of the in vitro drug-induced interferon-gamma release test in Stevens-Johnson syndrome

BACKGROUND

Drug-related T-cell activity in cutaneous drug reactions may be assessed by in vitro cytokine release tests. The diagnostic role of in vitro drug-induced interferon-gamma (IFN-gamma) release was evaluated in a patient with Stevens-Johnson syndrome.

CASE REPORT

Stevens-Johnson syndrome was diagnosed in a 58-year-old man, treated with colchicine (1 mg daily for 39 days) and allopurinol (300 mg daily for 13 days). Based on a clinical-epidemiologic score, allopurinol was more likely to be the causative agent. In vitro drug-induced IFN-gamma release test was conducted on this patient and on two controls, using an enzyme-linked immunoabsorbent assay (ELISA) technique. Increased IFN-gamma release was observed following an in vitro challenge of the patient's lymphocytes with allopurinol, but not following in vitro challenge with colchicine. An in vitro challenge with allopurinol in two control patients, treated with allopurinol without adverse drug reactions, did not induce a significant increase in IFN-gamma release.

CONCLUSIONS

The role of allopurinol as the drug responsible for the induction of Stevens-Johnson syndrome in our patient was confirmed by in vitro allopurinol-induced IFN-gamma release, which may indicate a drug-specific immune response.

Surgical treatment of children blinded by Stevens-Johnson syndrome

PURPOSE

The surgical treatment of severe Stevens-Johnson syndrome is considered to be very difficult, especially in children. However, ocular surface reconstruction is possible in certain cases.

METHODS

We have performed ocular surface reconstruction by allogeneic corneal epithelial stem cell transplantation in four children blinded by Stevens-Johnson syndrome.

RESULTS

Two cases failed, and the other two had excellent results. The successful cases had good lacrimal function and conjunctival epithelium, with clear corneal stroma and pathology limited to the superficial ocular tissue, whereas the failures did not.

CONCLUSIONS

The successful ocular surface reconstruction has been stable for more than 1 year in two cases, suggesting that some patients with Stevens-Johnson syndrome are very good candidates for ocular surface reconstruction, especially when the patients have good tear function and healthy conjunctival epithelium.

Management of rhinosinusitis in children

The authors provide definitions for the different forms of pediatric rhinosinusitis, with an enumeration of the main symptoms and signs. They also provide the indications for CT scan examination and microbiological investigations. In addition, they emphasize the importance of concomitant systemic disease, such as allergy and immunological disorders. The adequate medical management, which is mandatory before any surgery, is considered and discussed, and the indications for surgery are provided.

Thalidomide-induced toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a severe dermatologic disorder associated with mortality of up to 30%. Withdrawal of the causative agent is crucial in its management. Although thalidomide-induced dermatologic disorders rarely were reported before thalidomide was administered to patients positive for the human immunodeficiency virus, hypersensitivity reactions including rash are the agent's major dose-limiting toxicities in this population. As it is prescribed for other immunosuppressed patients, such as those with malignancies, the frequency of dermatologic reactions (including TEN) may increase. A 62-year-old woman developed TEN after approximately 5 weeks of thalidomide therapy for the treatment of a glioblastoma.

Side effects and mortality associated with use of phenytoin for early posttraumatic seizure prophylaxis

OBJECT

The goals of this study were to determine if the use of phenytoin to prevent early posttraumatic seizures following head injury was associated with significant adverse side effects and also to determine if the reduction in early posttraumatic seizures after phenytoin administration was associated with a change in mortality rates in head-injured patients.

METHODS

The authors performed a secondary analysis of the data obtained in a prospective double-blind placebo-controlled study of 404 patients who were randomly assigned to receive phenytoin or placebo for the prevention of early and late posttraumatic seizures. The incidence of adverse drug effects during the first 2 weeks of treatment, however, was low and not significantly different between the treated and placebo groups. Hypersensitivity reactions occurred in 0.6% of the patients in the phenytoin-treated group compared with 0% in the placebo group (p = 1.0) during week 1, and in 2.5% of phenytoin-treated compared with 0% of placebo-treated patients (p = 0.12) for the first 2 weeks of treatment. Mortality rates were also similar in both groups. Although the mortality rate was higher in patients who developed seizures, this increase was related to the greater severity of the injuries sustained by these patients at the time of the original trauma.

CONCLUSIONS

The results of this study indicate that the incidence of early posttraumatic seizure can be effectively reduced by prophylactic administration of phenytoin for 1 or 2 weeks without a significant increase in drug-related side effects. Reduction in posttraumatic seizure during the 1st week, however, was not associated with a reduction in the mortality rate.

Lamotrigine-associated rash: risk/benefit considerations in adults and children

PURPOSE

Lamotrigine (LTG) is an antiepileptic drug (AED) recently released in several countries. It is effective for a variety of seizure types in adults and children both as an add-on agent and in monotherapy, and is generally well tolerated. This report reviews the apparent risk factors for rash associated with LTG to determine whether and how the risk of serious rash can be minimized in practice.

METHODS

The panel of experts reviewed all published and unpublished data related to the incidence and risk factors for serious rash with LTG.

RESULTS

An allergic skin reaction occurs in approximately 10% of patients, usually in the first 8 weeks. Rashes leading to hospitalization, including Stevens-Johnson syndrome and hypersensitivity syndrome, occurred in approximately one of 300 adults and one of 100 children in clinical trials and appeared to be increased with overrapid titration when starting therapy and with concurrent valproate (VPA).

CONCLUSIONS

Recommendations are made for both minimizing the likelihood of serious rash and for management of rash in patients taking LTG. Risk of serious rash may possibly be lessened by strict adherence to manufacturer's dosing guidelines, particularly in patients who are at higher risk: those on concurrent VPA and in the pediatric population.

Low-dose diclofenac, naproxen, and ibuprofen cohort study

The risk of a newly diagnosed episode of upper gastrointestinal bleeding, acute liver and renal failure, agranulocytosis, aplastic anemia, severe skin disorders, and anaphylaxis was examined within 30 days after the first prescription for a low dose of diclofenac, naproxen, or ibuprofen in a cohort in the United Kingdom. We identified 22,146 persons using diclofenac (< or = 75 mg), 46,919 using naproxen (< or = 750 mg), and 54,830 using ibuprofen (< or = 1200 mg). Age, gender, and comorbidity were similar in the three cohorts. Overall 64 potential cases were identified, and 20 were confirmed by medical record review. Incidence rates (95% CI) of upper gastrointestinal bleeding/10,000 people using diclofenac, naproxen, and ibuprofen were 1.8 (0.5-4.6), 2.3 (1.2-4.2), and 0.4 (0.04-1.3), respectively. There were three cases of hepatic injury, one with naproxen and two with ibuprofen. Although low, the incidence of gastrointestinal toxicity remains the main serious adverse event for all study drugs.

Risk of Stevens-Johnson syndrome and toxic epidermal necrolysis during first weeks of antiepileptic therapy: a case-control study. Study Group of the International Case Control Study on Severe Cutaneous Adverse Reactions

BACKGROUND

There is still controversy about whether all antiepileptic drugs are associated with the severe cutaneous reactions Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). We have studied the role of antiepileptic drugs in SJS and TEN, taking into account potential cofactors that might confound or modify the risk.

METHODS

The case-control study in France, Italy, Germany, and Portugal identified cases of SJS/TEN that developed when the patient was not in hospital and were validated by an expert committee. Controls were patients admitted to the same hospital as the case for an acute illness or an elective procedure.

FINDINGS

73 (21%) of the 352 SJS/TEN cases and 28 (2%) of the 1579 controls reported intake of antiepileptic drugs. Among the 73 exposed SJS and TEN patients, 36 reported intake of phenobarbital, 14 of phenytoin, 21 of carbamazepine, 13 of valproic acid, and three of lamotrigine. Risk was highest in the first 8 weeks after onset of treatment. For individual antiepileptic drugs the univariate relative risk of SJS/TEN for 8 weeks or less of use was 57 (95% CI 16-360; multivariate risk 59 [12-302]) for phenobarbital; 91 (26-infinity) for phenytoin; 120 (34-infinity) for carbamazepine; 25 (5.6-infinity) for lamotrigine, and 24 (5.9-infinity) for valproic acid. The result for valproic acid was based on four case users, all of whom reported concurrent use of other associate drugs. The univariate relative risk for more than 8 weeks of use was 6.2 (2.4-17.0; multivariate risk 2.1 [0.5-9.3]) for phenobarbital, 1.2 (0-5.4) for phenytoin, 0.4 (0.02-2.1) for carbamazepine, and 7.0 (2.4-21.0; multivariate risk 2.0 [0.3-15.0]) for valproic acid.

INTERPRETATION

SJS and TEN are associated with short-term therapy with phenytoin, phenobarbital, and carbamazepine. The association with valproic acid seems to be confounded by concomitant short-term therapy with other causal drugs. Lamotrigine also has the potential for severe skin reactions. The period of increased risk is largely confined to the first 8 weeks of treatment.

Allergic skin reactions to anticonvulsant medications in patients receiving cranial radiation therapy

PURPOSE

Erythema multiforme and Stevens-Johnson syndrome have been associated with anticonvulsant medications (AEDs) in patients with brain tumors receiving cranial irradiation. AEDs are also known to cause mild drug rashes. The incidence of these complications has not been well studied among patients with brain tumors. We reviewed the records of patients with brain tumors treated with cranial radiation and AEDs to assess the frequency of both severe and mild skin reactions.

METHODS

Retrospective review of 289 radiotherapy records of consecutively treated patients from 1988 to 1993.

RESULTS

Only one of 289 patients developed erythema multiforme. Milder rashes, however, occurred in 18% of exposures to AEDs including 22% of exposures to phenytoin, compared with the expected rate of 5-10%. Most of the mild drug rashes occurred before the initiation of radiotherapy, suggesting that radiation was not the cause of these reactions.

CONCLUSIONS

Severe skin rashes are rare among patients with brain tumors receiving radiation therapy and AEDs. There is, however, an increased frequency of mild drug rashes among patients with brain tumors that does not appear related to radiation.

Progressive bronchial obstruction associated with toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is an acute life-threatening condition, characterized by erosion of the mucous membranes, extensive detachment of the epidermis, and severe constitutional symptoms. Pulmonary complications of TEN are reported as rare, but are one of the most common causes of death. Our report focuses on an unusual case of toxic epidermal necrolysis which showed multiple bronchial obliteration during the chronic phase of the disease. Biopsied tissue of the obliterated bronchi demonstrated non-specific granulation. To improve the obliterated ventilatory function, we tried to reopen the bronchial obliteration using a balloon catheter under the guidance of fibreoptic bronchoscopy, however rapid restenosis of the bronchi ensued.

Plasmapheresis as an adjunct treatment in toxic epidermal necrolysis

BACKGROUND

Toxic epidermal necrolysis (TEN) is a severe, progressive disease characterized by the sudden onset of skin necrosis. It is frequently associated with systemic involvement and has a high rate of morbidity and mortality. Standard therapy includes meticulous wound care, fluid replacement, and nutritional support in an intensive care setting.

OBJECTIVE

We evaluated the outcomes of patients treated in a burn unit for TEN over a 9-year period and compared the outcomes of a subset of patients treated with plasmapheresis with those managed by conventional means.

METHODS

The records of 16 patients with a diagnosis of TEN obtained from a computerized database were reviewed. Parameters recorded included extent of body surface area involvement and number of mucous membranes involved at admission, complications such as sepsis or need for mechanical ventilation, length of stay, and disposition.

RESULTS

Sixteen patients were included in this study. Ten were treated with conventional support measures alone. Six were treated with plasmapheresis. The average age was 42.4 years; the male/female ratio was 1:2.2. Sulfamethoxazole/trimethoprim was implicated in causation in 6 patients. The average extent of involvement on admission in all patients was 51.5% total body surface area. The average length of stay in all patients was 14.8 days. Eight patients (50%) were discharged home, 4 (25%) were discharged to a rehabilitation facility, and 4 (25%) died (2 of sepsis, 2 of cardiopulmonary arrest). None of the plasmapheresis-treated patients died.

CONCLUSION

Plasmapheresis is a safe intervention in extremely ill TEN patients and may reduce the mortality in this severe disease. Prospective studies are needed to further define its usefulness.

Increased risk of erythema multiforme major with combination anticonvulsant and radiation therapies

Erythema multiforme major (EMM; Stevens-Johnson syndrome) is a cutaneous disorder associated with a wide variety of factors including ingestion of drugs such as phenytoin and exposure to intracranial radiation therapy. Based on observations of a 47-year-old black man with brain metastases who developed EMM after combined phenytoin and radiation therapy, we conducted a MEDLINE literature search for articles on similar cases from 1966 to the present. Twenty cases were identified that support the hypothesis that EMM is associated with combined phenytoin and radiation therapy. The reaction, or its severity, has no relationship to the phenytoin or radiation therapy dosage, or to the histologic type of brain tumor. Also, EMM has no apparent age or gender predisposition in association with phenytoin-radiation therapy. Thus this is a clinical phenomenon that occurs with unusual frequency in patients with brain tumor who undergo radiation therapy while taking phenytoin. Phenytoin and other anticonvulsants such as phenobarbital and carbamazepine induce cytochrome P450 3A and produce oxidative reactive intermediates that may be implicated in hypersensitivity reactions such as EMM. Both carbamazepine and barbiturates have shown cross-sensitivity with phenytoin; furthermore, a case of EMM in a patient receiving carbamazepine and whole brain radiation therapy has been reported. As carbamazepine, valproate, and barbiturates have been associated with EMM, gabapentin may be considered as alternative anticonvulsant therapy when appropriate.

Comparative safety evaluation of non-narcotic analgesics

Both spontaneous reports and single outcome studies may distort the overall safety evaluation of drugs. We identified epidemiologic studies, published from January 1970 to December 1995, that investigated the association of serious adverse effects with aspirin, diclofenac, acetaminophen, and dipyrone to determine and compare the excess mortality associated with short-term drug use. The estimated excess mortality due to community-acquired agranulocytosis, aplastic anemia, anaphylaxis, and serious upper gastrointestinal complications was 185 per 100 million for aspirin, 592 per 100 million for diclofenac, 20 per 100 million for acetaminophen, and 25 per 100 million for dipyrone. The estimates were largely influenced by the excess mortality associated with upper gastrointestinal complications. A relative risk estimate of 300 or more for the association of dipyrone with agranulocytosis would have been necessary for the excess mortality of dipyrone to be comparable to that of aspirin or diclofenac. Based on published epidemiologic evidence used to determine the excess mortality associated with short-term use of these four non-narcotic analgesics, the current regulatory ranking of the drugs appears inappropriate.

[Detection and evaluation of adverse drug reactions]

Adverse drug reactions (ADRs) occur in about 5% of drug-treated patients. Hospital admissions are caused by ADRs in 5% of patients and roughly 2% of hospitalized patients will experience an ADR. The economic burden of ADRs can only be estimated. Type A reactions can be explained by the pharmacological action of the drugs, and are preventable in many cases. However, Type B reactions involving the immune system and/or idiosyncratic reactions occur rarely and most of them are not fully understood. Genotyping represents an elegant method to explain the presence of abnormal enzyme activities and allows prediction of adverse drug effects in individual cases. Typical time frames have been identified for the occurrence of hypersensitivity reactions, although definite causality assessment is often impeded due to the absence or unavailability of specific laboratory tests and the impossibility of rechallenge. Diagnosis of an ADR is often difficult due to comorbidity and polypharmacy, thus causality assessment is often divergent even between specialists. In Germany, ADRs are reported preferably to the manufacturer of the suspicious drug and then collected and evaluated at the Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM. However, total number and quality of reported ADRs could be improved.

Randomised comparison of thalidomide versus placebo in toxic epidermal necrolysis

BACKGROUND

Toxic epidermal necrolysis (TEN) is associated with a 30% death rate. Tumour necrosis factor alpha (TNF-alpha) has been implicated in the pathogenesis of TEN. Thalidomide is a potent inhibitor of TNF-alpha action. We did a double-blind, randomised, placebo-controlled study of thalidomide in TEN.

METHODS

The patients received a 5-day course of thalidomide 400 mg daily or placebo. The main endpoint was the progression of skin detachment after day 7. Secondary endpoints were the severity of the disease, evaluated with the simplified acute physiology score (SAPS), and the mortality. TNF-alpha and interleukin 6 were measured.

FINDINGS

The study was stopped because there was excess mortality in the thalidomide group--ten of 12 patients died compared with three of ten in the placebo group (Fisher's exact test with Katz's approximation, relative risk=2.78, p=0.03). After adjustment for SAPS, mortality remained significantly higher in the thalidomide group than in the placebo group (exact logistic regression mid-p=0.007; 95% CI for odds ratio 2.7 to infinity). Plasma TNF-alpha concentration was higher in the thalidomide group than the placebo group on day 2, though the difference was not significant (Wilcoxon rank-sum test p=0.07).

INTERPRETATION

Even though few patients were included, our data suggest that thalidomide is detrimental in TEN, possibly because of a paradoxical enhancement of TNF-alpha production.

Lamotrigine-induced severe cutaneous adverse reactions

PURPOSE

We systematically reviewed and analyzed published and unpublished cases of Stevens-Johnson syndrome (SJS), or toxic epidermal necrolysis (TEN) associated with lamotrigine (LTG) therapy to identify characteristics of these reactions.

METHODS

We performed a MEDLINE search (January 1985 to April 1998) and citation tracking for published reports. In addition, reports were requested from the Uppsala Monitoring Centre of the World Health Organization (WHO). Published and WHO cases of LTG-associated SJS or TEN were included if the causal relationship was assessed as either possible, probable, or definite.

RESULTS

We identified a total of 57 cases (43 cases of SJS, 14 cases of TEN), of which 13 (23%) were published. Cases in the SJS group were significantly younger than in the TEN group (21 years vs. 31 years). The median time to onset (17 days for SJS and TEN) and the median dosage at onset (50 mg vs. 87.5 mg) for SJS and TEN did not differ significantly. Concomitant use of valproate (VPA) was reported in 74% of the SJS cases and 64% of the TEN cases. In three cases, TEN was the cutaneous manifestation of the antiepileptic drug hypersensitivity syndrome (AHS).

CONCLUSIONS

The main features of severe cutaneous drug reactions, such as dosage, onset, and concomitant VPA use, do not differ in patients with LTG-induced SJS or TEN. SJS or TEN may also be the cutaneous manifestations of LTG-induced AHS. Further epidemiologic studies are needed to identify the incidence of severe LTG-induced cutaneous adverse reactions and the relative risk compared with other AEDs.

Acute management of hypersensitivity reactions and seizures

The most crucial step in the management of an antiepileptic drug (AED) hypersensitivity reaction is the recognition of the clinical syndrome and cessation of the presumed offending agent. The severity of the developing reaction will shape the course of treatment because multiple organ systems may become affected. Management of conjunctival involvement and treatment of skin lesions dominate care, with patients whose skin lesions are extensive benefitting from treatment in a structured burn unit. Neutropenia and sepsis are common and potentially fatal complicating factors. The use of steroids remains controversial, as is the utility of immune modulation with other agents such as cyclophosphamide and i.v. immunoglobulin. Acute treatment of seizures should be addressed with i.v. benzodiazepines, given either intermittently or by continuous infusion. Choice of long-term maintenance AEDs should take into consideration the crossreactivity among AEDs that share an arene oxide metabolite.

Rash in adult and pediatric patients treated with lamotrigine

Data from clinical trials with lamotrigine indicate that the risk of serious rash in pediatric patients is higher than in adults. The incidence of rash associated with hospitalization among adults treated with lamotrigine is 0.3% and among pediatric patients 1.0%. The incidence of cases reported as possible Stevens-Johnson syndrome is 0.1% for adult patients and 0.5% for pediatric patients. These rates reflect lamotrigine dosing and concomitant AEDs used in these trials, both of which are risk factors for rash. Since many of the trials were conducted prior to the establishment of the current dosing recommendations, the incidence of serious rash in clinical trials does not necessarily reflect the incidence to be expected with use of current dosing recommendations. The higher incidence of serious rash in pediatric patients may at least partially be accounted for by the differential effects of the risk factors of dosing and concomitant use of valproic acid in these patients.

Stevens-Johnson syndrome caused by a health drink (Eberu) containing ophiopogonis tuber

Stevens-Johnson syndrome is considered to be a severe type of erythema exsudativum multiforme. It is characterized by erythema with bullous and eroded lesions of skin and mucous membranes. We report a case of Steven-Johnson syndrome following consumption of a health drink containing ophiopogonis tuber. A 66-year-old female took an O.T.C. health drink for fever. The next morning, she noted erythema and swelling of her face, neck, and chest. She started to develop bullous and eroded lesions on the skin of her entire body and the mucous membranes of her oral cavity, conjunctiva, and cornea, and she became feverish. She had high degrees of corneal erosion and liver dysfunction. Skin biopsy showed diffuse necrosis of the epidermis. After admission to the hospital, steroid pulse therapy (1000 mg/day of methylprednisolone sodium succinate) was continued for 5 days. The health drink induced a positive drug lymphocyte stimulation test (DLST) and patch test. A challenge test was done with a one hundredth dose, and it was positive. We did patch tests with all components of the drink and found that Mai-Meu-Dong-Tang (ophiopogonis) alone was positive at 72 hours. There is no previous report of Stevens-Johnson syndrome caused by a health drink or Mai-Meu-Dong-Tang. Even though it is a health drink, we should be aware of the possibility of a severe reaction.

Oral manifestations of toxic epidermal necrolysis (TEN) in patients with AIDS: report of five cases

OBJECTIVE

To describe oral findings in HIV-infected individuals with toxic epidermal necrolysis (TEN).

PATIENTS

In a retrospective study over a 10 year period the medical histories of 931 hospitalised HIV-infected patients were reviewed for the occurrence of TEN.

RESULTS

Five cases of TEN were diagnosed (three men, two women; median age: 41 years; median CD4+ T lymphocyte count: 20/microliter). Four patients had been treated with biweekly pyrimethamine/sulfadoxine for prophylaxis against Pneumocystis carinii pneumonia and toxoplasmosis. In one patient flucloxacillin was administered. Signs of TEN with cutaneous epidermolysis occurred and patients showed oral lesions characterized as oropharyngeal blisters and bullae on the palate, buccal mucosa, tongue and floor of the mouth initially. Antibiotics and corticosteroids were administered; none of the patients died.

CONCLUSION

Longacting sulfonamides and antibiotics have been implicated as the cause of severe mucocutaneous reactions. Since rash and oral blisters may be the first signs of TEN in patients receiving these it is mandatory to follow up these patients closely to detect oral or cutaneous changes indicating the development of TEN.

Covalent binding of carbamazepine reactive metabolites to P450 isoforms present in the skin

Carbamazepine is an anticonvulsant associated with a high risk for severe cutaneous reactions. Upon metabolism by cytochrome P450, carbamazepine may produce reactive metabolites. We evaluated in vitro the covalent binding of carbamazepine reactive metabolites on human P450s and then the presence of these P450s in human epidermis. Carbamazepine reactive metabolites covalent binding to human liver microsomes involved P450 subfamilies 1A, 2C and 3A. Specific covalent binding to yeasts expressing different P450s showed that carbamazepine reactive metabolites bound specifically to P450 1A2 and 3A4. We confirmed the constitutive presence of P450 3A in human epidermis and after induction with coaltar of P450 1A. Consequently, the production in epidermis of carbamazepine reactive metabolites is theoretically possible with formation of P450 adduct metabolites.