Understanding drug allergies

Drug-induced hypersensitivity reactions in a Lebanese outpatient population: A decade-long retrospective analysis (2012-2021)

Background

Drug hypersensitivity reactions (DHRs) are becoming more common as a result of increasing prevalence and case complexity. Allergists and clinical immunologists worldwide are challenged daily to adequately diagnose and manage these reactions. Data in the literature regarding DHR outpatient consultations are scarce worldwide, limited in the Middle East, and currently unavailable in Lebanon.

Objective

This retrospective study aimed to evaluate the characteristics of all reported DHRs over 10 years in a tertiary-care allergy clinic in Lebanon.

Methods

We conducted a decade-long (2012-21) retrospective analysis of the archived medical records of patients with a history of DHRs. Demographics, clinical history, diagnostic tools, and characteristics of the DHRs were collected and analyzed.

Results

A total of 758 patients experienced DHRs to therapeutic molecules provided for ambulatory care. Our results identified 72 medications. The most frequently implicated drug classes included β-lactam antibiotics (53.8%), followed closely by nonsteroidal anti-inflammatory drugs (48.9%). Of the 758 patients, 32.6% reported DHRs to multiple molecules, and 11.8% reported concomitant DHRs to 1 or several molecules provided in the perioperative setting. Of those, opioids and neuromuscular blocking agents were the 2 most common therapeutic classes. Furthermore, we evaluated the cross-reactivity between molecules of the same class. In neuromuscular blocking agents, rocuronium and cisatracurium were the most commonly cross-reactive, and for opioids, the most common association we recorded was with morphine and pethidine.

Conclusion

Our findings constitute the first step toward a more comprehensive evaluation of the clinical characteristics of DHRs in Lebanon.

Risk of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Associated With Antibiotic Use: A Case-Crossover Study

BACKGROUND

Evidence is lacking on the association between antibiotic use and risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in Asians.

OBJECTIVE

We assessed the risk of SJS/TEN associated with different antibiotic classes in Japanese.

METHODS

We conducted a case-crossover study using a claims database. Firth conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of SJS/TEN associated with antibiotic use in a 56-day hazard period versus 3 control periods. We created 18 cohorts for each antibiotic class and calculated 56-day cumulative incidence per 100,000 new users. The association between antibiotic class and SJS/TEN was also evaluated in each case using the ALgorithm of Drug causality for Epidermal Necrolysis (ALDEN).

RESULTS

Our case-crossover study included 170 SJS/TEN cases. Increased ORs were observed for lincomycins (OR, 33.00 [95% CI, 3.74-4332.05]), trimethoprim-sulfamethoxazole (21.20 [6.73-105.98]), penicillins (14.39 [6.95-34.21]), glycopeptides (14.37 [3.17-136.10]), cephalosporins (7.06 [4.25-12.21]), aminoglycosides (6.55 [1.97-26.84]), quinolones (5.98 [3.34-11.20]), fosfomycin (5.40 [1.20-30.97]), carbapenems (5.09 [1.85-15.64]), tetracyclines (4.95 [1.78-15.27]), and macrolides (3.78 [2.13-6.83]). Cumulative incidence of SJS/TEN was 67.4 for trimethoprim-sulfamethoxazole, 86.2 for glycopeptides, and below 10.0 for the others. Despite the high incidence, only 2 cases had a probable causal relationship with glycopeptides.

CONCLUSION

Some antibiotic classes, including lincomycins, glycopeptides, aminoglycosides, fosfomycin, and carbapenems, were newly suggested to be associated with risk of SJS/TEN; considered together with the high incidence for trimethoprim-sulfamethoxazole and glycopeptides, these findings warrant caution in clinical practice.

Penicillin Allergy in Pregnancy: Moving From "Rash" Decisions to Accurate Diagnosis

The emergence of beta-lactam-resistant pathogenic organisms has resulted in limitation or even elimination of drugs such as penicillin and ampicillin from available antibiotic choices for treating common infections in obstetrics and gynecology. In clinical situations for which penicillins and cephalosporins are appropriate or recommended first-line agents, the problem of patient-reported penicillin allergies has led to routine use of alternative but potentially less effective agents. The use of broader-spectrum and potentially suboptimal alternative antibiotic regimens for intrapartum antibiotic prophylaxis against group B streptococcus or for surgical prophylaxis for cesarean delivery in women with a reported penicillin allergy may affect these women during labor and birth. Most individuals who report a penicillin allergy are neither truly allergic nor at risk of developing a hypersensitivity reaction after exposure to penicillin. The available evidence suggests that there are important roles for both targeted history-taking, to determine the nature of drug allergies and penicillin allergy testing in pregnant women, to optimize their antibiotic-related treatment both during pregnancy and for their lifetimes. Wider consideration and adoption of penicillin allergy testing in pregnant women specifically, as well as the general population of women cared for by providers of obstetrics and gynecology, is recommended.

Drug-induced Stevens-Johnson syndrome and toxic epidermal necrolysis in vietnamese spontaneous adverse drug reaction database: A subgroup approach to disproportionality analysis

WHAT IS KNOWN AND OBJECTIVE

Despite the numerous studies investigating drug-induced Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), the understanding and quantitative data in developing countries remain limited. The study aimed to describe and quantify the drug-related risk of SJS/TEN in a resource-limited context using the Vietnamese spontaneous reporting database (VSRD) of adverse drug reactions.

METHODS

Spontaneous reports relating to medium- and late-onset severe cutaneous adverse reactions (MLOSCAR) and SJS/TEN recorded in the VSRD from 2010 to 2015 were retrospectively analysed. The demographic characteristics and drug information were described and compared between SJS/TEN and other MLOSCAR reports. The drug-induced SJS/TEN signals were estimated using subgrouped disproportionality analysis with calculation of the reporting odds ratio (ROR) and the respective 95% confidence interval (CI).

RESULTS

The VSRD received 2,849 MLOSCAR reports, 136 of which focus on SJS/TEN over a 6-year period. About 60% of SJS/TEN patients were male, and the majority of them were adults (mean age 42.5 ± 22.9). Up to 91.8% of drugs induced SJS/TEN within 1-28 days, and 45% SJS/TEN cases were evaluated as life-threatening. Positive signals were generated with carbamazepine (n = 25, ROR [95% CI] = 11.99 [7.07-19.92]), allopurinol (n = 15, ROR [95% CI] = 4.2 [2.20-7.59]), traditional/herbal medicines (n = 7, ROR [95% CI] = 2.76 [1.12-5.86]), colchicine (n = 4, ROR [95% CI] = 6.22 [1.69-18.72]), valproic acid (n = 3, ROR [95% CI] = 8.71 [1.89-30.19]) and meloxicam (n = 3, ROR [95% CI] = 7.09 [1.55-24.29]), which are well known for SJS/TEN. Cefixime (n = 5, ROR [95% CI] = 3.34 [1.13-8.00]) and paracetamol (n = 22, ROR [95% CI] = 5.23 [3.10-8.49]) also generated positive signals despite their popularity in Vietnam.

WHAT IS NEW AND CONCLUSION

This first Vietnamese population-based study has highlighted original characteristics and signals of drug-induced SJS/TEN, which are relatively consistent with other worldwide data and typical for a developing country.

Type B adverse drug reactions reported by an immunoallergology department

Objective:

Characterization of the adverse drug reactions (ADR) reported by the immunoallergology department (IAD), Centro Hospitalar de São João (Porto), to the Northern Pharmacovigilance Centre (NPC).

Methods:

An observational, descriptive and retrospective study was conducted, based in a spontaneous report system. Participants were all the patients from the IAD, with suspected ADR, reported to NPC by specialists after the study was completed.

Results:

Studied population had a median age of 41 years, with the predominance of the female gender (73.2%). Allergic rhinitis and asthma were the most frequent comorbidities. All studied ADR were type B, 89.6% were serious, 86.4% unexpected and 2.6% associated with drugs that presented less than 2 years in the market. The most represented drug classes were the non-steroidal anti-inflammatory drugs (NSAIDs) (52.6%) and antibiotics (25.2%). Skin symptoms represented 61.2% of the reported complaints. About 52.9% of these ADR occurred in less than one hour after intake. The most frequent ADR treatment at the time of the reaction was drug interruption (86.2%), followed by the prescription of anti-histamines (42.2%).

Conclusions:

Reported ADR to NPC by the Drug Alert Unit were mainly serious, unexpected, associated with NSAIDs and antibiotics and related with marketing authorization medicines older than two years. These results could be very useful to develop strategies to prevent the clinical and economic consequences of ADR.

Retrospective Analysis of Pattern of Cutaneous Adverse Drug Reactions in Tertiary Hospital of Pauri Garhwal

INTRODUCTION

Cutaneous Adverse Drug Reactions (CADR) are the common drug induced adverse reactions which usually have wide range of manifestations and severity.

AIM

To describe the prevalence and clinical spectrum of CADR's in a tertiary hospital of the Garhwal region in Uttarakhand, India.

MATERIALS AND METHODS

All patients suspected of having CADRs reported in the various out-patient departments, and in-patients of HNB Base & Teaching Hospital, from 1(st) January 2012 to 31(st) December 2014 were retrospectively analysed. Drug history was recorded in a format specified in Indian National Pharmacovigilance Programme.

RESULTS

Total 111 cases of CADRs were reported from Jan 2012 to Dec 2014. Mean age of patients was 33.34±18.7 years and maximum ADRs were reported in the age group of 20-39 years (36.9%). Female were affected more than male (W:M :: 66:45). Most of the ADRs were exanthematous eruptions (EE) type (33.3%). Medicine department reported maximum cases of CADRs (47.7%), followed by Dermatology. Most of the CADRs were reported with antimicrobial agents (69.4%). Significant associations of different types of various cutaneous reactions were observed in relation to the duration (in days) of ADRs (p = 0.038), types of outcome (p= 0.006), different departments (p= 0.014) and between different groups of medicines (p = 0.008).

CONCLUSION

CADRs have proved a significant problem in healthcare for decades. Major bulk of CADR result from physician prescribed drugs. Hence, awareness on part of the physician can help in timely detection of cutaneous reactions, thereby restricting damage from them.

Diagnosis and management of immediate hypersensitivity reactions to cephalosporins

Cephalosporins can cause a range of hypersensitivity reactions, including IgE-mediated, immediate reactions. Cephalosporin allergy has been reported with use of a specific cephalosporin, as a cross-reaction between different cephalosporins or as a cross-reaction to other β-lactam antibiotics. Unlike penicillins, the exact allergenic determinants of cephalosporins are less well understood and thus, standardized diagnostic skin testing is not available. Nevertheless, skin testing with diluted solutions of cephalosporins can be valuable in confirming IgE-mediated hypersensitivity reactions. In vitro tests are in development using recent technological advances and can be used as complementary tests. However, they are not commonly used because of their reduced sensitivity and limited availability. In selected cases of inconclusive results in both skin tests and IgE assays, a graded challenge or induction of drug tolerance with the implicated cephalosporin should be performed.

The skin prick test - European standards

Skin prick testing is an essential test procedure to confirm sensitization in IgE-mediated allergic disease in subjects with rhinoconjunctivitis, asthma, urticaria, anapylaxis, atopic eczema and food and drug allergy. This manuscript reviews the available evidence including Medline and Embase searches, abstracts of international allergy meetings and position papers from the world allergy literature. The recommended method of prick testing includes the appropriate use of specific allergen extracts, positive and negative controls, interpretation of the tests after 15 – 20 minutes of application, with a positive result defined as a wheal ≥3 mm diameter. A standard prick test panel for Europe for inhalants is proposed and includes hazel (Corylus avellana), alder (Alnus incana), birch (Betula alba), plane (Platanus vulgaris), cypress (Cupressus sempervirens), grass mix (Poa pratensis, Dactilis glomerata, Lolium perenne, Phleum pratense, Festuca pratensis, Helictotrichon pretense), Olive (Olea europaea), mugwort (Artemisia vulgaris), ragweed (Ambrosia artemisiifolia), Alternaria alternata (tenuis), Cladosporium herbarum, Aspergillus fumigatus, Parietaria, cat, dog, Dermatophagoides pteronyssinus, Dermatophagoides farinae, and cockroach (Blatella germanica). Standardization of the skin test procedures and standard panels for different geographic locations are encouraged worldwide to permit better comparisons for diagnostic, clinical and research purposes.

Antibiotics to reduce post-tonsillectomy morbidity

BACKGROUND

This is an update of a Cochrane Review first published in The Cochrane Library in Issue 2, 2008 and previously updated in 2010.Tonsillectomy continues to be one of the most common surgical procedures performed in children and adults. Despite improvements in surgical and anaesthetic techniques, postoperative morbidity, mainly in the form of pain, remains a significant clinical problem. Postoperative bacterial infection of the tonsillar fossa has been proposed as an important factor causing pain and associated morbidity, and some studies have found a reduction in morbid outcomes following the administration of perioperative antibiotics.

OBJECTIVES

To determine whether perioperative antibiotics reduce pain and other morbid outcomes following tonsillectomy.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 20 March 2012.

SELECTION CRITERIA

All randomised controlled trials examining the impact of perioperative administration of systemic antibiotics on post-tonsillectomy morbidity in children or adults.

DATA COLLECTION AND ANALYSIS

Two authors independently collected data. Primary outcomes were pain, consumption of analgesia and secondary haemorrhage (defined as significant if patient re-admitted, transfused blood products or returned to theatre, and total (any documented) haemorrhage). Secondary outcomes were fever, time taken to resume normal diet and activities and adverse events. Where possible, we generated summary measures using random-effects models.

MAIN RESULTS

Ten trials, comprising a pooled total of 1035 participants, met the eligibility criteria. Most did not find a significant reduction in pain with antibiotics. Similarly, antibiotics were mostly not shown to be effective in reducing the need for analgesics. Antibiotics were not associated with a reduction in significant secondary haemorrhage rates (risk ratio (RR) 0.49, 95% CI 0.08 to 3.11, P = 0.45) or total secondary haemorrhage rates (RR 0.90, 95% CI 0.56 to 1.44, P = 0.66). With regard to secondary outcomes, antibiotics reduced the proportion of patients with fever (RR 0.63, 95% CI 0.46 to 0.85, P = 0.002).

AUTHORS' CONCLUSIONS

The present systematic review, including meta-analyses for select outcomes, suggests that although individual studies vary in their findings, there is no evidence to support a consistent, clinically important impact of antibiotics in reducing the main morbid outcomes following tonsillectomy (i.e. pain, need for analgesia and secondary haemorrhage rates). The limited benefit apparent with antibiotics may be a result of positive bias introduced by several important methodological shortcomings in the included trials. Based on existing evidence, therefore, we would advocate against the routine prescription of antibiotics to patients undergoing tonsillectomy. Whether a subgroup of patients who might benefit from selective administration of antibiotics exists is unknown and needs to be explored in future trials.

Rhizobium etli asparaginase II: an alternative for acute lymphoblastic leukemia (ALL) treatment

Bacterial l-asparaginase has been a universal component of therapies for childhood acute lymphoblastic leukemia since the 1970s. Two principal enzymes derived from Escherichia coli and Erwinia chrysanthemi are the only options clinically approved to date. We recently reported a study of recombinant l-asparaginase (AnsA) from Rhizobium etli and described an increasing type of AnsA family members. Sequence analysis revealed four conserved motifs with notable differences with respect to the conserved regions of amino acid sequences of type I and type II l-asparaginases, particularly in comparison with therapeutic enzymes from E. coli and E. chrysanthemi. These differences suggested a distinct immunological specificity. Here, we report an in silico analysis that revealed immunogenic determinants of AnsA. Also, we used an extensive approach to compare the crystal structures of E. coli and E. chrysantemi asparaginases with a computational model of AnsA and identified immunogenic epitopes. A three-dimensional model of AsnA revealed, as expected based on sequence dissimilarities, completely different folding and different immunogenic epitopes. This approach could be very useful in transcending the problem of immunogenicity in two major ways: by chemical modifications of epitopes to reduce drug immunogenicity, and by site-directed mutagenesis of amino acid residues to diminish immunogenicity without reduction of enzymatic activity.

Resistance evolution in HIV - modeling when to intervene

The treatment of HIV is complicated by the evolution of antiviral drug resistant virus and the limited availability of antigenically independent antiviral regimens. The consequences to the patient of successive virological failures is such that many strategies to minimize the occurrence of such failures are being investigated. In this paper, a Markov chain-based model of virological failure is introduced. This model considers sequential failure events, and differentiates between several modes of virological failure. This model is then used to evaluate the resistance- targeted interventions by means of testing the impact of a viral load preconditioning strategy on total treatment regimen longevity in HIV patients. It is shown that a proposed intervention targeting pre-existing resistance has the potential to increase the expected time to three sequential virological failures by an average of 3.3 years per patient. When combined with an intervention targeting patient compliance, the total potential increase in the time to three sequential virological failures is as high as 11.2 years. The impact on patient and public health is discussed.

Electrochemiluminescence in bioanalysis

The discovery of electrochemiluminescence (ECL) and its development as a means of detection is truly a success story. Although studies describing ECL were published in the early 1960s, most studies using ECL as a means of detection were not widely published until the mid 1990s. Incorporating ECL into assays provides increased sensitivity, several logs of dynamic range and the ability to electronically control the reaction. These characteristics provide advantages over assays that rely on radioisotopic labels, fluorescence and enzymatic activity. There have been many areas of science that have benefited from the use of ECL, including environmental microbiology, virology, neurobiology, molecular biology and immunology. ECL has improved the understanding and treatment of infectious diseases, cancer, neurodegenerative diseases and even sleep apnea disorders. Drug development has also benefited from ECL via improved assessment of pharmacodynamics, pharmacokinetics and determining immune responses against protein-based therapeutics. This review provides an overview of ECL chemistry and principles with a more detailed emphasis on the applications of ECL-based assays in different areas of science and medicine. The primary purpose of this review is to provide an in-depth discussion of the impact that ECL-based analysis has had on microbiology, immunology, virology, neurodegenerative diseases, molecular biology and drug development. Examples of ECL-based bioanalysis in each of these fields are discussed in conjunction with an overview of ECL principles and instrumentation.

[Hypersensitivity reactions to antituberculous therapy]

INTRODUCTION

Hypersensitivity reactions to antituberculous drugs pose both a diagnostic and a therapeutic problem. This work aims to study the frequency of allergic reactions to antituberculous drugs, their clinical presentations and the diagnostic approach required.

PATIENTS AND METHODS

This retrospective study covered the period from January 1990 to June 2008 at the Ibn Nafis Pulmonary Department of Abderrahmen Mami Hospital in Ariana. It dealt with 30 in-patients who experienced an allergic reaction to antituberculous drugs.

RESULTS

Cutaneous manifestations were the most frequent (80% of cases), predominantly urticarial. Thrombocytopenia was noted in two cases, anaphylactic shock in three cases, a systemic toxidermia in two cases and renal failure in one patient. Pyrazinamide was implicated in most cases (28%) when only one drug was considered to be responsible for the reaction. Interrupting either one drug or the whole treatment was necessary to define the cause of the reaction. The clinical evolution of hypersensitivity signs was favorable in all cases following definitive withdrawal of the responsible drug. Complete recovery from tuberculosis occurred in all cases.

CONCLUSION

Close monitoring of patients on antituberculous treatment is required to detect the onset of any allergic reaction and ensure an adequate compliance with treatment.

Antibiotics to reduce post-tonsillectomy morbidity

BACKGROUND

This is an update of a Cochrane Review first published in The Cochrane Library in Issue 2, 2008.Tonsillectomy continues to be one of the most common surgical procedures performed in children and adults. Despite improvements in surgical and anaesthetic techniques, postoperative morbidity, mainly in the form of pain, remains a significant clinical problem. Postoperative bacterial infection of the tonsillar fossa has been proposed as an important factor causing pain and associated morbidity, and some studies have found a reduction in morbid outcomes following the administration of perioperative antibiotics.

OBJECTIVES

To determine whether perioperative antibiotics reduce pain and other morbid outcomes following tonsillectomy.

SEARCH STRATEGY

We searched the Cochrane ENT Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 4), MEDLINE (1950 to 2009) and EMBASE (1974 to 2009). The date of the last search was 30 October 2009.

SELECTION CRITERIA

All randomised controlled trials examining the impact of perioperative administration of systemic antibiotics on post-tonsillectomy morbidity in children or adults.

DATA COLLECTION AND ANALYSIS

Two authors independently collected data. Primary outcomes were pain, consumption of analgesia and secondary haemorrhage (defined as significant if patient re-admitted, transfused blood products or returned to theatre, and total (any documented) haemorrhage). Secondary outcomes were fever, time taken to resume normal diet and activities and adverse events. Where possible, we generated summary measures using random-effects models.

MAIN RESULTS

Ten trials, comprising a pooled total of 1035 participants, met the eligibility criteria. Most did not find a significant reduction in pain with antibiotics. Similarly, antibiotics were mostly not shown to be effective in reducing the need for analgesics. Antibiotics were not associated with a reduction in significant secondary haemorrhage rates (relative risk (RR) 0.49, 95% CI 0.08 to 3.11, P = 0.45) or total secondary haemorrhage rates (RR 0.90, 95% CI 0.56 to 1.44, P = 0.66). With regard to secondary outcomes, antibiotics reduced the proportion of subjects with fever (RR 0.63, 95% CI 0.46 to 0.85, P = 0.002).

AUTHORS' CONCLUSIONS

The present systematic review, including meta-analyses for select outcomes, suggests that although individual studies vary in their findings, there is no evidence to support a consistent, clinically important impact of antibiotics in reducing the main morbid outcomes following tonsillectomy (i.e. pain, need for analgesia and secondary haemorrhage rates). Limited benefit apparent with antibiotics may be a result of positive bias introduced by several important methodological shortcomings in the included trials. Based on existing evidence therefore, we would advocate against the routine prescription of antibiotics to patients undergoing tonsillectomy. Whether a subgroup of patients who might benefit from selective administration of antibiotics exists is unknown and needs to be explored in future trials.

Adverse cutaneous drug reaction

In everyday clinical practice, almost all physicians come across many instances of suspected adverse cutaneous drug reactions (ACDR) in different forms. Although such cutaneous reactions are common, comprehensive information regarding their incidence, severity and ultimate health effects are often not available as many cases go unreported. It is also a fact that in the present world, almost everyday a new drug enters market; therefore, a chance of a new drug reaction manifesting somewhere in some form in any corner of world is unknown or unreported. Although many a times, presentation is too trivial and benign, the early identification of the condition and identifying the culprit drug and omit it at earliest holds the keystone in management and prevention of a more severe drug rash. Therefore, not only the dermatologists, but all practicing physicians should be familiar with these conditions to diagnose them early and to be prepared to handle them adequately. However, we all know it is most challenging and practically difficult when patient is on multiple medicines because of myriad clinical symptoms, poorly understood multiple mechanisms of drug-host interaction, relative paucity of laboratory testing that is available for any definitive and confirmatory drug-specific testing. Therefore, in practice, the diagnosis of ACDR is purely based on clinical judgment. In this discussion, we will be primarily focusing on pathomechanism and approach to reach a diagnosis, which is the vital pillar to manage any case of ACDR.

Drug provocation tests in children: Indications and interpretation

Drug provocation tests in children are always a problematic task. In the present article the most important aspects of this technique are reviewed, including the differences between children and adults; the main mechanisms involved in drug reaction; how to perform the different tests; and when they are indicated.

Antibiotics to reduce post-tonsillectomy morbidity

BACKGROUND

Tonsillectomy continues to be one of the most common surgical procedures performed in children and adults. Despite improvements in surgical and anaesthetic techniques, postoperative morbidity, mainly in the form of pain, remains a significant clinical problem. Postoperative bacterial infection of the tonsillar fossa has been proposed as an important factor causing pain and associated morbidity, and some studies have found a reduction in morbid outcomes following the administration of perioperative antibiotics.

OBJECTIVES

To determine whether perioperative antibiotics reduce pain and other morbid outcomes following tonsillectomy.

SEARCH STRATEGY

Cochrane ENT Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2007), MEDLINE (1950 to 2007) and EMBASE (1974 to 2007) were searched. The date of the last search was March 2007.

SELECTION CRITERIA

All randomised controlled trials examining the impact of perioperative administration of systemic antibiotics on post-tonsillectomy morbidity in children or adults.

DATA COLLECTION AND ANALYSIS

Two authors independently collected data. Primary outcomes were pain, consumption of analgesia and secondary haemorrhage (defined as significant if patient re-admitted, transfused blood products or returned to theatre, and total if any documented haemorrhage). Secondary outcomes were fever, time taken to resume normal diet and activities and adverse events. Where possible, summary measures were generated using random-effects models.

MAIN RESULTS

Nine trials met the eligibility criteria. Most did not find a significant reduction in pain with antibiotics. Similarly, antibiotics were not shown to be effective in reducing the need for analgesics. Antibiotics were not associated with a reduction in significant secondary haemorrhage rates (Relative Risk (RR) 0.49, 95% CI 0.08 to 3.11, P = 0.45) or total secondary haemorrhage rates (RR 0.92, 95% CI 0.45 to 1.87, P = 0.81). With regard to secondary outcomes, antibiotics reduced the proportion of subjects with fever (RR 0.63, 95% CI 0.46 to 0.85, P = 0.002).

AUTHORS' CONCLUSIONS

The present review suggests that there is little or no evidence that antibiotics reduce the main morbid outcomes following tonsillectomy (i.e. pain, the need for analgesia or secondary haemorrhage rates). They do however appear to reduce fever. Some important methodological shortcomings exist in the included trials which are likely to have produced bias favouring antibiotics. We therefore advocate caution when prescribing antibiotics routinely to all patients undergoing tonsillectomy. Whether a subgroup of patients who might benefit from selective administration of antibiotics exists is unknown and needs to be explored in future trials.

Cutaneous reactions to drugs in children

Cutaneous eruptions are a commonly reported adverse drug reaction. Cutaneous adverse drug reactions in the pediatric population have a significant impact on patients' current and future care options. A patient's recollection of having a "rash" when they took a medication as a child is a frequent reason for not prescribing a particular treatment. The quick detection and treatment of cutaneous adverse drug reactions, plus identification of the causative agent, are essential for preventing the progression of the reaction, preventing additional exposures, and ensuring the appropriate use of medications for both the current condition and others as the patient ages. The purpose of this review is to discuss a reasonable approach to recognition and initial management of cutaneous adverse drug reactions in children.

Sulfonamide allergies and outcomes related to use of potentially cross-reactive drugs in hospitalized patients

STUDY OBJECTIVES

To characterize patient-reported sulfonamide allergies, assess the influence of these allergies on drug prescribing practices, and determine the frequency and nature of adverse reactions in patients with sulfonamide allergies who receive potentially cross-reactive drugs.

DESIGN

Prospective observational study.

SETTING

Tertiary care hospital.

PATIENTS

Ninety-four hospitalized adult patients with reported sulfonamide allergies.

MEASUREMENTS AND MAIN RESULTS

Patients were followed during their hospital stay to document prescribing of and adverse reactions to sulfonamide antibiotics and sulfonamide nonantibiotics. Allergy characteristics and prescribing of sulfonamide-containing drugs were analyzed with descriptive statistics. Trimethoprim-sulfamethoxazole (TMP-SMX) allergy was reported by 42 patients (45%), whereas 42 patients (45%) did not recall the drug to which they were allergic. Fifty-nine patients (63%) reported the allergy's physical manifestation as rash, 13 (14%) anaphylaxis, and 2 (2)% Stevens-Johnson's syndrome. Median time since last reported allergic reaction to a sulfonamide-containing agent was 20 years. Forty patients (43%) had been taking a sulfonamide nonantibiotic as an outpatient for an average of 6.2 years; 24 (60%) of those patients took furosemide. Sixteen (40%) of the patients receiving sulfonamide nonantibiotics reported an allergy to TMP-SMX. Nine patients (10%) with no past sulfonamide nonantibiotic use received a sulfonamide nonantibiotic as an inpatient, with furosemide most commonly prescribed. No adverse events were reported before admission or observed during the inpatient stay (range 2-23 days).

CONCLUSIONS

Inpatient and outpatient use of potentially cross-reactive drugs was observed in 52% of patients, although numerous patients were unable to give an accurate allergy history. No adverse effects were reported or documented with outpatient or inpatient sulfonamide nonantibiotic use, even among patients with histories of life-threatening reactions to sulfonamides.

Intravenous Linezolid Administered Orally: A Novel Desensitization Strategy

A 41-year-old woman with a history of myasthenia gravis was admitted to a local hospital because of severe muscle weakness, ptosis, shortness of breath, nausea and vomiting, and fever. Blood cultures revealed Enterococcus faecium resistant to several antimicrobial agents. The organism had minimum inhibitory concentrations above 16 microg/ml for vancomycin and above 2 microg/ml for quinupristin-dalfopristin. In the absence of therapeutic alternatives, treatment with linezolid was required (minimum inhibitory concentration 1.5 microg/ml). The first dose of linezolid resulted in a hypersensitivity reaction consistent with an immunoglobulin E-mediated response requiring medical intervention. Because of a lack of intravenous access and because of limited availability of the oral suspension from the manufacturer, a desensitization protocol was implemented in which the intravenous formulation of linezolid was given orally. The patient was successfully desensitized by using an escalating, 14-dose procedure. We believe this is the first case in the English language literature to describe successful desensitization with the oral administration of intravenous linezolid in a patient with E. faecium bacteremia who was allergic to oxazolidinone.

The usefulness of skin tests to prove drug hypersensitivity

BACKGROUND

Suspected drug hypersensitivity is common. Only a minority of cutaneous adverse drug reactions (CADRs) are allergic in origin and will reappear after the next exposure. Methods to confirm suspected CADRs are needed and skin testing could serve as one possibility.

OBJECTIVES

To analyse the usefulness of skin tests in revealing drug allergy. The relevance of skin test results was evaluated with drug provocation studies.

METHODS

During 1989-2001, 947 patients with a history of suspected CADR were examined with skin tests including patch tests (PTs) (826 patients), skin prick tests (SPTs) (935 patients) and photopatch tests (12 patients). The occurrence of positive and negative test reactions to different drugs was correlated with clinical history. Drug provocation was carried out in 246 patients.

RESULTS

Antimicrobial drugs were suspected and tested most often. A positive PT reaction to one or more drug was seen in 89 of 826 (10.8%), most often to beta-lactams, clindamycin and trimethoprim. A positive SPT reaction was seen in 10 of 935 (1.1%) patients. Challenge was carried out in 17 patients with positive skin test results. Thirteen of 16 (81.2%) PT positives developed exanthema, three remained negative and one SPT-positive patient developed urticaria. Among skin test negatives, 207 of 229 (90.4%) challenges were negative and 22 of 229 (9.6%) were positive, 12 with exanthema, three with fixed drug eruptions and seven with urticaria.

CONCLUSIONS

Skin testing, especially the PT, was a useful screening method to find a cause of CADR if the reaction was exanthema and if antimicrobial, cardiovascular or antiepileptic drugs were suspected. The SPT detected occasional positives with antimicrobials. In cases of fixed drug eruption, PTs performed at the earlier reaction site were useful. When skin tests are negative or dubious, oral challenge should be carried out to confirm the association.

Antigen-IgE desensitization in signal transducer and activator of transcription 6-deficient mast cells by suboptimal doses of antigen

BACKGROUND

Rapid administration of suboptimal antigen induces transient unresponsiveness in patients with IgE antibodies to beneficial medications, but the molecular mechanisms of desensitization are poorly understood. Mast cells (MCs) have been implicated as the target cells.

OBJECTIVE

To establish a physiologic model of IgE-antigen desensitization using mouse bone marrow-derived MCs (mBMMCs) from wild-type and signal transducer and activator of transcription 6 (STAT6)-deficient mice.

METHODS

The mBMMCs were sensitized with dinitrophenyl (DNP) IgE or trinitrophenyl (TNP) IgE and activated with DNP/TNP-human serum albumin. For desensitization, suboptimal doses of DNP/TNP-human serum albumin were administered at fixed intervals.

RESULTS

Desensitized mBMMCs failed to respond to an optimal dose of antigen, indicating successful desensitization. Desensitization was time dependent, with 5 minutes of antigen exposure being optimal. Resensitization with DNP-IgE did not reverse the process. The desensitized cells were responsive to calcium ionophore and phorbol myristate acetate. Thus, the desensitization reaction alters an early event in the high-affinity IgE receptor (FcepsilonRI)-dependent signaling pathway in a nontoxic manner. The mBMMCs from STAT6-null mice could not be desensitized by suboptimal doses of antigen.

CONCLUSIONS

Mast cells can be rendered unresponsive by rapid administration of suboptimal doses of antigen in the presence of calcium, similar to in vivo desensitizations. The STAT6-null mBMMCs cannot be desensitized, providing the first molecular target in this inhibitory process.

Arzneimittelallergien

Cutaneous adverse drug reactions (ADR) are common and encompass a broad clinical spectrum. Since the skin acts as a signaling organ for ADR, the dermatologist plays a key role in their diagnosis. Only a minor part of cutaneous ADR are due to underlying allergic mechanisms. Among these, delayed-type reactions such as maculopapular exanthems and immediate-type reactions such as urticaria and angioedema predominate. Risk factors for the development of cutaneous allergic ADR may be related to the patient (e.g. certain HLA-types), the drug (e.g. its reactivity), and underlying conditions (e.g. viral infections). Antibiotics, non-steroidal anti-inflammatory agents and anticonvulsive medications are most often reported to be causally related.

Genetic aspects of immune-mediated adverse drug effects

Adverse drug effects (ADEs) are of great importance in medicine and account for up to 5% of all hospital admissions. ADEs can arise from several mechanisms and a wide range of drugs can cause immune-mediated ADEs (IMADEs). For a drug to elicit an IMADE, it must be both immunogenic (that is, able to sensitize the immune system) and antigenic (that is, able to evoke a response from a sensitized immune system). Unlike protein therapeutics, small-molecule drugs (or xenobiotics) are usually neither immunogenic nor antigenic. IMADEs are therefore the result of complex interactions between drug-metabolizing enzymes, immune sensitization and immune effectors. The genetic aspects of this interplay are discussed in this review.

Non-allergic nature of docetaxel-induced acute hypersensitivity reactions

Based on observations of a discrepancy between 'hypersensitivity' reactions to docetaxel (DT) and the clinical features of allergic reactions, we explored the hypothesis that DT-induced acute hypersensitivity reactions (AHRs) have a non-allergic origin. Forty cancer patients receiving DT and 16 patients receiving other potentially allergenic chemotherapeutic agents were included in the study. All DT patients received standard pre- and post-medication. Before, during and after administration of the drugs, clinical symptoms and signs were recorded, and serial blood sampling was performed for the first 2 cycles for all patients or in all subsequent cycles in case of AHRs. Plasma histamine and serum tryptase, two established drug allergy markers, were measured. Seventy-five chemotherapy sessions were evaluable. Nine patients on DT, two on paclitaxel (PT) and one on pegylated doxorubicin experienced an AHR during the first course of chemotherapy. In all cases, heart rate remained stable or increased, while arterial pressure was unchanged or raised; no hypotension or bradycardia was noted. All episodes resolved with discontinuation of drug and did not reappear during a re-challenge with the same agent 30 min later. Tryptase levels were normal in all pre- and post-exposure samples (post-exposure: 11.32+/-35.63 microg/l, normal values <13.5 microg/l). In all but one AHR-free PT, pre- and post-exposure histamine concentrations remained normal (post-exposure: 2.86+/-11.88 nM, normal values <10 nM). No eosinophilia or basophilia was observed. We conclude that 'hypersensitivity' reactions to DT seem not to be histamine or tryptase mediated; thus, their allergenic nature should be questioned. The underlying mechanism may be related to other biological processes such as the release of vasoactive molecules or non-histamine/tryptase-mediated allergy. If the former is demonstrated by further study, the safety of DT administration will be confirmed, and the pre- and post-medication practice might be revisited.

Represcription of penicillin after allergic-like events

OBJECTIVE

We sought to determine the frequency of represcription of penicillin to individuals with penicillin allergy and the risk of a second reaction in those who had a previous reaction.

METHODS

A retrospective cohort study was conducted within the UK General Practice Research Database. All patients who had received a prescription for penicillin were identified. Within that source population, records of patients who had received at least 2 prescriptions for penicillin at least 60 days apart were selected and examined for allergic-like (hypersensitivity) events on the day of or within 30 days after a prescription.

RESULTS

At least one prescription for penicillin was given to 3,375,162 patients. Of 6212 (0.18%) patients who experienced an allergic-like event after the initial prescription, 48.5% were given a second prescription compared with 59.8% of those without an initial allergic-like event (risk ratio, 0.81; 95% CI, 0.79-0.83). Two or more prescriptions for penicillin were given to 2,017,957 patients. Three thousand fourteen (0.15%) patients experienced an allergic-like event after the first prescription, and 57 (1.89%) of those had another event after the second prescription. The unadjusted odds ratio of an allergic-like event after the second prescription for those who experienced an allergic-like event after the first prescription, compared with those who had no initial event was 11.2 (95% CI, 8.6-14.6). Adjusting for confounding had no substantive effect on this result.

CONCLUSION

The risk of an allergic-like event after penicillin is markedly increased in those who have had a prior event, although the absolute difference is small (1.72%). Represcription of penicillin to such patients is more frequent than anticipated.

Allergic and Nonallergic Drug Reactions

Allergic drug reactions may be difficult to distinguish from nonallergic reactions. In this article, we review a pragmatic approach to the management of adverse drug reactions on the basis of knowledge of the classification and patterns of these reactions. Algorithms for management of patients with a previous adverse drug reaction who require treatment for the same indication, and the approach to a patient who experiences a drug reaction while on multiple drugs, are presented.

IgE-mediated immediate-type hypersensitivity to the pyrazolone drug propyphenazone

BACKGROUND

Propyphenazone (1,2-dihydro-1,5-dimethyl-4-(1-methylethyl)-2-phenyl-3H-pyrazol-3-one; PP) is a nonsteroidal anti-inflammatory drug frequently used as mild analgesic medicament. It belongs to the chemical group of pyrazolones. Severe adverse reactions to PP are frequent and have generally been regarded as pseudoallergic or intolerance reactions. Presently, there are no useful in vitro test systems available for the detection of antibodies directed against analgesic drugs.

OBJECTIVE

The purpose of this study was to unequivocally demonstrate that IgE-mediated Type I allergy is the main mechanism leading to immediate-type adverse reactions to the analgesic drug PP.

METHODS

We investigated 53 young adult patients with adverse reactions to PP. All patients developed symptoms suggestive of IgE-mediated anaphylaxis within 30 minutes after intake of a painkiller containing PP. Patients were subjected to skin tests (prick test and intracutaneous test). In addition, a novel ELISA system was developed to prove the existence of specific IgE antibodies in patients' sera.

RESULTS

In 44 of 53 (83%) patients, skin tests showed typical wheal and flare reactions. Significant amounts of PP-specific serum IgE was detected in 31 of 53 (58%) of the serum samples. Moreover, in 7 of 9 patients with skin test negative results, PP-specific IgE could be detected. The assay was PP-specific because only PP, but no other pyrazolone derivative (antipyrine, aminophenazone, or metamizol), was able to inhibit IgE-binding in the system.

CONCLUSION

Propyphenazone is a sensitizing agent in susceptible individuals and can elicit IgE-mediated anaphylaxis. By using skin tests and our ELISA system we were able to confirm Type I allergy in 51 of 53 (96%) patients in this study.

Preventing and managing drug-induced anaphylaxis

Drug-induced anaphylaxis and anaphylactoid reactions have increased in frequency with more widespread use of pharmaceutical agents. Anaphylaxis is a systemic, severe immediate hypersensitivity reaction caused by immunoglobulin (Ig) E-mediated immunological release of mediators of mast cells and basophils. An anaphylactoid reaction is an event similar to anaphylaxis but is not mediated by IgE. The incidence of anaphylactic or anaphylactoid reactions differs amongst classes of medications. Antibacterials are the most usual offenders, and penicillins are the most studied. Other compounds commonly causing reactions include non-steroidal anti-inflammatory drugs, anaesthetics, muscle relaxants, latex and radiocontrast media. Prevention, if possible, is the purpose of detailed patient history taking and physical examination. Simple strategies can be employed to decrease the risk of anaphylaxis. These include consideration of the route of drug administration, identification of patients with known causes of anaphylaxis, and the knowledge that certain medications cross react and are contraindicated in those with known history of anaphylaxis. Tests are available, and include IgE-specific skin tests and radioallergosorbent tests. Penicillins are the only compounds whose antigenic determinants are well documented, it is therefore difficult to determine the negative predictive value of other compounds tested. Oral challenge remains an alternative, though entails risk. Desensitisation procedures, as well as gradual dose escalation protocols, are available and can be implemented based on patient history and diagnostic testing. The management of anaphylaxis is based on control of the airway, breathing and circulation. Treatment consists of epinephrine (adrenaline) and supportive measures. Rapid diagnosis and intervention are important in these life-threatening reactions. After stabilisation, all individuals with a documented history of anaphylaxis require a Medic-Alert bracelet or necklace, and an identification card for their wallet or purse.