Sulfonamide Hypersensitivity: Fact and Fiction

Liver injury associated with endothelin receptor antagonists: a pharmacovigilance study based on FDA adverse event reporting system data

BACKGROUND

Endothelin receptor antagonists are commonly used in clinical practice, with concerns about their hepatotoxicity.

AIM

This study aimed to conduct a comprehensive pharmacovigilance study based on FDA adverse event reporting system data to evaluate the possible association between endothelin receptor antagonists and drug-induced liver injury.

METHOD

Adverse event reports from FDA adverse event reporting system between January 2004 and December 2022 were analyzed. Disproportionality algorithms, including reporting odds ratio and information component, were used to evaluate the association between endothelin receptor antagonists and liver injury. Sex- and age-stratified analyses of drug-induced liver injury events were also conducted in relation to endothelin receptor antagonists.

RESULTS

Significant associations between bosentan, macitentan, and liver injury were identified. Bosentan showed a strong link with liver injury, with reporting odds ratios for cholestatic injury at 7.59 (95% confidence interval: 6.90-8.35), hepatocellular injury at 5.63 (5.29-6.00), and serious drug-related hepatic disorders events at 1.33 (1.24-1.43). Drug-induced liver injury signals associated with bosentan were detected in all age groups. Macitentan was associated with liver injury, with reporting odds ratios for hepatic failure at 1.64 (1.39-1.94), cholestatic injury at 1.62 (1.43-1.83), and serious drug-related hepatic disorders events at 1.40 (1.29-1.51). No drug-induced liver injury signal was detected for ambrisentan, and no significant sex differences were observed in drug-induced liver injury events.

CONCLUSION

Both bosentan and macitentan are associated with liver injury. Routine monitoring of serum aminotransferase levels is recommended, especially in patients at higher risk of liver injury. Further research into drug-drug interactions involving endothelin receptor antagonists is warranted.

Impact of Sulfonamide Allergy Label on Clinical Outcomes in Patients with Pneumocystis jirovecii Pneumonia

INTRODUCTION

The presence of antibiotic allergy labels can have harmful impacts on clinical outcomes, particularly among immunosuppressed patients, in whom there have been associations with increased complications, readmission rates, and mortality. We explore the effects of a sulfonamide allergy label (SAL) on clinical outcomes in adult patients with Pneumocystis jirovecii pneumonia (PJP).

METHODS

In this retrospective matched cohort study, we utilized TriNetX, a multicenter national database, to match 535 adult patients with PJP and SAL to an equal number of controls. We identified cases indexed between 01/01/2010 and 01/01/2023 utilizing ICD-10 codes for PJP and allergy status to sulfonamides and through detection of P. jirovecii antigen with immunofluorescence or PCR. Propensity score matching was performed in a 1:1 fashion for demographics and comorbidities, and our analysis included clinical outcomes that occurred within 30 days after the occurrence of the index event.

RESULTS

While hospitalization risk tended to be lower among patients with SAL as compared to controls (RR: 0.90; 95% CI 0.81-1.01), there were no major differences in the risk of respiratory failure (RR: 0.94; 95% CI 0.84-1.05), prednisone use (RR: 1; 95% CI 0.91-1.10), intensive level of care requirement (RR: 0.85; 95% CI 0.69-1.06), intubation (RR: 0.85; 95% CI 0.61-1.19), or mortality (RR: 0.98; 95% CI 0.68-1.42). The presence of SAL did however impact antibiotic prescription patterns, with an underutilization of trimethoprim (RR: 0.50; 95% CI 0.43-0.59) and sulfamethoxazole (RR, 0.47; 95% CI 0.40-0.56) and overuse of alternative agents by patients with SAL as compared to controls. Yet, there was no difference in the occurrence of adverse outcomes such as hepatotoxicity (RR: 1.09; 95% CI 0.49-2.45) or acute kidney injury (RR: 0.94; 95% CI 0.78-1.14) between patients with SAL and controls.

CONCLUSIONS

The presence of SAL alters antibiotic prescription patterns among adults with Pneumocystis infection but has no clinically significant impact on outcomes.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part I. Epidemiology, pathogenesis, clinicopathological features, and prognosis

Drug-induced hypersensitivity syndrome (DiHS), also known as drug reaction with eosinophilia and systemic symptoms (DRESS), is a severe cutaneous adverse reaction (SCAR) characterized by an exanthem, fever, and hematologic and visceral organ involvement. Anticonvulsants, antibiotics, and allopurinol are the most common triggers. The pathogenesis involves a complex interplay between drugs, viruses, and the immune system primarily mediated by T-cells. DiHS/DRESS typically presents with a morbilliform eruption 2-6 weeks after drug exposure, and is associated with significant morbidity, mortality, and risk of relapse. Long-term sequelae primarily relate to organ dysfunction and autoimmune diseases. Part I of this continuing medical education activity on DiHS/DRESS provides an update on epidemiology, novel insights into pathogenesis, and a description of clinicopathological features and prognosis.

How to Define and Manage Low-Risk Drug Allergy Labels

Risk stratification in drug allergy implies that specific risk categories (eg, low, moderate, and high) classify historical drug hypersensitivity reactions. These risk categories can be based on reaction phenotypic characteristics, the timing of the reaction and evaluation, the required reaction management, and individual characteristics. Although a multitude of frameworks have been described in the literature, particularly for penicillin allergy labels, there has yet to be a global consensus, and approaches continue to vary between allergy centers. Immune-mediated drug allergies can sometimes be confirmed using skin testing, but a negative drug challenge is required to demonstrate tolerance and remove the allergy from the electronic health record ("delabel" the allergy). Even for quintessential IgE-mediated drug allergy, penicillin allergy, recent data reveal that a direct oral challenge, without prior skin testing, is an appropriate diagnostic strategy in those who are considered low-risk. Drug allergy pathogenesis and clinical manifestations may vary depending on the culprit drug, and as such, the optimal approach should be based on risk stratification that considers individual patient and reaction characteristics, the likely hypersensitivity reaction phenotype, the drug class, and the patient's clinical needs. This article will describe low-risk drug allergy labels, focusing on β-lactam and sulfonamide antibiotics, nonsteroidal anti-inflammatory drugs, iodinated contrast media, and common chemotherapeutics. This review will also address practical management approaches using currently available risk stratification and clinical decision tools.

A Comprehensive Review of Sulfonamide Hypersensitivity: Implications for Clinical Practice

Sulfonamides, which are drugs commonly prescribed in hospital and outpatient settings, have historically been associated with a high incidence of hypersensitivity reactions. It is believed that there is an increased risk of cross-reactions with other drugs that contain this functional group in their structure. However, it has not been conclusively established that the sulfonamide group is the sole cause of hypersensitivity reactions, as non-antibiotic sulfonamides do not share the same accessory groups with antibiotic sulfonamides. Therefore, cross-reactivity between different types of sulfonamides and sulfonamide-type antibiotics is not clearly demonstrated, and allergic reactions may involve other mechanisms. Misinformation about this topic can lead to inappropriate use of alternative antibiotics with lower efficacy or higher adverse effects, contributing to antibiotic resistance. It is crucial to individualize and monitor patients with a history of allergies to sulfonamide-type antibiotics when introducing a new drug containing sulfa and manage any adverse reactions promptly. Desensitization protocols may be a viable option for patients who specifically benefit from these antibiotics, particularly those who are immunosuppressed. This article provides a descriptive bibliographic review to update information on sulfa allergy, its prevalence, management, and recommendations to prevent such reactions and optimize pharmacotherapy, without underusing these drugs.

Simultaneous hypersensitivity reactions to trimethoprim-sulfamethoxazole and amoxicillin-clavulanate in a dog

Antibiotics are known to be able to cause hypersensitivity reactions through various mechanisms. We present a case of drug-induced immune thrombocytopenia (DITP) and anaphylactic shock occurring simultaneously in a dog after the administration of two classes of antibiotics, namely trimethoprim-sulfamethoxazole (TMP-SMX) and amoxicillin-clavulanate (AMC). The patient recovered completely from DITP on discontinuation of TMP-SMX and the anaphylactic shock caused by AMC was treated with intensive care. DITP is a rare adverse drug reaction (ADR), and anaphylactic shock is a life-threatening ADR. This is the first case report of a dog manifesting two types of hypersensitivity reactions caused by two antibiotics.

Drug-microbiota interactions: an emerging priority for precision medicine

Individual variability in drug response (IVDR) can be a major cause of adverse drug reactions (ADRs) and prolonged therapy, resulting in a substantial health and economic burden. Despite extensive research in pharmacogenomics regarding the impact of individual genetic background on pharmacokinetics (PK) and pharmacodynamics (PD), genetic diversity explains only a limited proportion of IVDR. The role of gut microbiota, also known as the second genome, and its metabolites in modulating therapeutic outcomes in human diseases have been highlighted by recent studies. Consequently, the burgeoning field of pharmacomicrobiomics aims to explore the correlation between microbiota variation and IVDR or ADRs. This review presents an up-to-date overview of the intricate interactions between gut microbiota and classical therapeutic agents for human systemic diseases, including cancer, cardiovascular diseases (CVDs), endocrine diseases, and others. We summarise how microbiota, directly and indirectly, modify the absorption, distribution, metabolism, and excretion (ADME) of drugs. Conversely, drugs can also modulate the composition and function of gut microbiota, leading to changes in microbial metabolism and immune response. We also discuss the practical challenges, strategies, and opportunities in this field, emphasizing the critical need to develop an innovative approach to multi-omics, integrate various data types, including human and microbiota genomic data, as well as translate lab data into clinical practice. To sum up, pharmacomicrobiomics represents a promising avenue to address IVDR and improve patient outcomes, and further research in this field is imperative to unlock its full potential for precision medicine.

Expanding the Histologic Spectrum of Sudden Conjunctivitis, Lymphopenia, and Rash Combined With Hemodynamic Changes

ABSTRACT

Sudden conjunctivitis, lymphopenia, and rash combined with hemodynamic changes (SCoRCH) is a recently described hypersensitivity reaction to trimethoprim-sulfamethoxazole. To date, only 1 case of histologic findings in SCoRCH has been reported, revealing a superficial perivascular dermatitis. In this article, we present a 53-year-old woman with a four-day history of a widespread, confluent, erythematous, and dusky rash after exposure to trimethoprim-sulfamethoxazole. Histologic examination revealed a vacuolar interface dermatitis with several apoptotic keratinocytes at multiple levels of the epidermis, similar to an erythema multiforme-like presentation. As described in SCoRCH, our patient's clinical findings rapidly improved within 48 hours of presentation without treatment. This case adds to the current literature by identifying a newly described histopathological presentation of SCoRCH.

Direct challenges are the gold standard for most antibiotic allergy evaluations

Antibiotic allergies are frequently encountered in clinical practice, and delabeling of these allergies has individual and public health benefits. This review focuses on the evidence supporting graded challenges without preceding skin testing in adult and pediatric patients to the major groups of antibiotics including penicillins, cephalosporins, sulfamethoxazole, fluoroquinolones, tetracyclines, macrolides, metronidazole, carbapenems, and aztreonam. The cost savings, time savings, and evidence for performing graded challenges outside of an allergy/immunology office are also reviewed for graded challenges to penicillins.

[Drug allergy: Fundamental aspects in diagnosis and treatment.]

BACKGROUND

Any substance used as a treatment for any disease can produce harmful or unpleasant events called adverse drug reactions (ADRs). They are due to inherent biological effects of the drug and are caused by immunological and non-immunological mechanisms.

OBJECTIVES

To describe the immunological mechanisms of hypersensitivity reactions (HSR) to drugs, their epidemiology, risk factors, classification, clinical manifestations, diagnosis, treatment, and prognosis.

METHODS

A review of the most current literature in English and Spanish was carried out, in the main databases, related to the HSR of various drug groups.

RESULTS

This study describes the terms used to define ADRs and HSRs, their classification and clinical manifestations, current diagnostic tools, treatment algorithms and prognosis of the most frequently used medications and with the highest prevalence of reported adverse events.

CONCLUSION

ADRs are a challenging entity, with a complex pathophysiology that has not been fully understood. Its approach requires a careful consideration since not all drugs have validated tests for their diagnosis nor a specific treatment. When indicating the use of any drug, the severity of the disease, the availability of other treatments and the potential risks of developing future adverse events should always be taken into consideration.

Detection of Hepatic Drug Metabolite-Specific T-Cell Responses Using a Human Hepatocyte, Immune Cell Coculture System

Drug-responsive T-cells are activated with the parent compound or metabolites, often via different pathways (pharmacological interaction and hapten). An obstacle to the investigation of drug hypersensitivity is the scarcity of reactive metabolites for functional studies and the absence of coculture systems to generate metabolites in situ. Thus, the aim of this study was to utilize dapsone metabolite-responsive T-cells from hypersensitive patients, alongside primary human hepatocytes to drive metabolite formation, and subsequent drug-specific T-cell responses. Nitroso dapsone-responsive T-cell clones were generated from hypersensitive patients and characterized in terms of cross-reactivity and pathways of T-cell activation. Primary human hepatocytes, antigen-presenting cells, and T-cell cocultures were established in various formats with the liver and immune cells separated to avoid cell contact. Cultures were exposed to dapsone, and metabolite formation and T-cell activation were measured by LC-MS and proliferation assessment, respectively. Nitroso dapsone-responsive CD4+ T-cell clones from hypersensitive patients were found to proliferate and secrete cytokines in a dose-dependent manner when exposed to the drug metabolite. Clones were activated with nitroso dapsone-pulsed antigen-presenting cells, while fixation of antigen-presenting cells or omission of antigen-presenting cells from the assay abrogated the nitroso dapsone-specific T-cell response. Importantly, clones displayed no cross-reactivity with the parent drug. Nitroso dapsone glutathione conjugates were detected in the supernatant of hepatocyte immune cell cocultures, indicating that hepatocyte-derived metabolites are formed and transferred to the immune cell compartment. Similarly, nitroso dapsone-responsive clones were stimulated to proliferate with dapsone, when hepatocytes were added to the coculture system. Collectively, our study demonstrates the use of hepatocyte immune cell coculture systems to detect in situ metabolite formation and metabolite-specific T-cell responses. Similar systems should be used in future diagnostic and predictive assays to detect metabolite-specific T-cell responses when synthetic metabolites are not available.

New Ni(II) and Pd(II) complexes bearing derived sulfa drug ligands: synthesis, characterization, DFT calculations, and in silico and in vitro biological activity studies

In the present study, the synthesis of six new Ni(II) and Pd(II) complexes with three derived sulfamethoxazole drug ligands is reported. The coordination mode, geometry, and chemical formula of all the synthesized compounds have been determined by elemental analysis, mass spectrometry, emission atomic spectroscopy, conductivity measurements, magnetic susceptibility, FTIR, TGA, 1H-NMR, electronic absorption spectroscopy, SEM-EDX along with DFT calculations. The Schiff Base ligands were found to be bidentate and coordinated to the metal ions through sulfonamidic nitrogen and oxazolic nitrogen atoms leading to a square planar geometry for palladium (II) while a distorted octahedral geometry around Nickel (II) ion was suggested. Biological applications of the new complexes including in vitro antimicrobial, antioxidant and anticancer properties were investigated. The results showed that the new metal (II) compounds exhibit remarkable antibacterial inhibition activity against both Gram-positive and Gram-negative bacteria, in addition to noticeable DPPH free radical scavenging activity. The in vitro cytotoxicity assay of the complexes against cell lines of chronic myelogenous leukaemia (K562) showed promising potential for the application of the coordination compounds in antitumor therapy. Subsequently, to evaluate the pharmaceutical potential of the metal-containing compounds, pharmacokinetics and toxicity were studied by ADMET simulations while interactions between the complexes and bacterial proteins were evaluated by molecular docking.

Viral infections and drug hypersensitivity

Virus infections and T-cell-mediated drug hypersensitivity reactions (DHR) can influence each other. In most instances, systemic virus infections appear first. They may prime the reactivity to drugs in two ways: First, by virus-induced second signals: certain drugs like β-lactam antibiotics are haptens and covalently bind to various soluble and tissue proteins, thereby forming novel antigens. Under homeostatic conditions, these neo-antigens do not induce an immune reaction, probably because co-stimulation is missing. During a virus infection, the hapten-modified peptides are presented in an immune-stimulatory environment with co-stimulation. A drug-specific immune reaction may develop and manifest as exanthema. Second, by increased pharmacological interactions with immune receptors (p-i): drugs tend to bind to proteins and may even bind to immune receptors. Without viral infections, this low affine binding may be insufficient to elicit T-cell activation. During a viral infection, immune receptors are more abundantly expressed and allow more interactions to occur. This increases the overall avidity of p-i reactions and may even be sufficient for T-cell activation and symptoms. There is a situation where the virus-DHR sequence of events is inversed: in drug reaction with eosinophilia and systemic symptoms (DRESS), a severe DHR can precede reactivation and viremia of various herpes viruses. One could explain this phenomenon by the massive p-i mediated immune stimulation during acute DRESS, which coincidentally activates many herpes virus-specific T cells. Through p-i stimulation, they develop a cytotoxic activity by killing herpes peptide-expressing cells and releasing herpes viruses. These concepts could explain the often transient nature of DHR occurring during viral infections and the often asymptomatic herpes-virus viraemia after DRESS.

Acute Pain Management Pearls: A Focused Review for the Hospital Clinician

Acute pain management is a challenging area encountered by inpatient clinicians every day. While patient care is increasingly complex and costly in this realm, the availability of applicable specialists is waning. This narrative review seeks to support diverse hospital-based healthcare providers in refining and updating their acute pain management knowledge base through clinical pearls and point-of-care resources. Practical guidance is provided for the design and adjustment of inpatient multimodal analgesic regimens, including conventional and burgeoning non-opioid and opioid therapies. The importance of customized care plans for patients with preexisting opioid tolerance, chronic pain, or opioid use disorder is emphasized, and current recommendations for inpatient management of associated chronic therapies are discussed. References to best available guidelines and literature are offered for further exploration. Improved clinician attention and more developed skill sets related to acute pain management could significantly benefit hospitalized patient outcomes and healthcare resource utilization.

Case report: Uncommon immune-mediated skin disease involving systemic disorders in dogs

Case 1, a 6-year-old, spayed female Pug, presented with severe systemic urticaria, edema, and erythema. The dog had received a famotidine injection as a treatment for repeated vomiting in another hospital. On physical examination, hyperthermia was observed. Moderate pancytopenia, hypoalbuminemia, and increased CRP and D-dimer were also observed in blood tests. Hyposthenuric proteinuria, pulmonary interstitial infiltration, and hepatomegaly were found in other tests. In the histology of the skin, dermal edema and infiltration of inflammatory cells were observed. Therefore, she was diagnosed with acute systemic hypersensitivity. Case 2, a 13-month-old, neutered male Pembroke welsh corgi, presented with severe and patchy systemic ulcerative skin lesions. The dog had a history of soft feces and pain around the anus 2 days before. Thrombocytopenia, and increased CRP and D-dimer were observed in blood tests. In histology, epidermal necrolysis, separation of the epidermis and dermis, and infiltration of inflammatory cells were observed. Therefore, he was diagnosed with an immune-mediated disease with necrolysis dermatitis. Case 3, a 12-year-old, spayed female Pomeranian, presented with severe systemic alopecia, pustule, and crust on the skin. The dog had received an infection treatment from a local hospital. Severe regenerative anemia (hematocrit 15.3%, negative saline agglutination test, negative slide agglutination test, negative Coomb's test, prominent spherocytes) elevated liver enzymes, and increased CRP and D-dimer were observed in blood tests. On histopathology of the skin, pustules, acantholytic cells, and inflammatory cells were observed in the keratin layer of the epithelium. Therefore, she was diagnosed with Pemphigus foliaceus concurrent with immune-mediated hemolytic anemia. The 3 cases were diagnosed with fatal immune-mediated skin disease concurrently with hematological and systemic abnormalities. All the cases were treated with immune-suppressive drugs, prednisolone, and cyclosporine. In cases 2 and 3, the dogs also received human intravenous immunoglobulin as an immune modulator. The treatment was successful with significant improvements in all the 3 cases.

Feasibility of trimethoprim/sulfamethoxazole desensitization therapy in hematological diseases

The effectiveness and safety of trimethoprim/sulfamethoxazole (TMP/SMX) desensitization therapy is insufficiently evaluated in hematological diseases. From 2002 to 2019, we retrospectively analyzed 112 patients with hematological diseases who underwent desensitization therapy after TMP/SMX prophylaxis withdrawal due to adverse events. They orally started TMP/SMX at 0.4 mg/2 mg, which was then increased daily to 80 mg/400 mg for 5 or 9 days. Eighty-eight patients (79%) had complete desensitization, and the major reason for failure was rash seen in 21 cases (19%). The cause of desensitization and reasons for failure matched in 22 cases (92%). Pneumocystis pneumonia was not observed throughout the study. In the failure group, the number of eosinophils and alanine aminotransferase (ALT) levels were significantly increased after desensitization. In particular in the failure group, the slight increase in eosinophils was seen through the beginning to halfway during desensitization (36/μL (0-900/μL) and 48/μL (0-2560/μL), respectively, p = 0.025). These data show that TMP/SMX desensitization therapy is effective and safe in hematological diseases. The recurrence of adverse events could help predict desensitization success.

Clinical Manifestations and Genetic Influences in Sulfonamide-Induced Hypersensitivity

Drug hypersensitivity is an inflammatory or immune reaction induced by drugs. It can be fatal if not appropriately treated and cause the risk of long-term complications. Sulfonamides are classified as antimicrobial drugs with a broad spectrum effective for gram-positive and gram-negative bacteria. This antibacterial agent works by competitively inhibiting folic acid synthesis, which prevents the growth and proliferation of microorganisms. In its use as antibiotics, sulfonamides can also cause adverse reactions in specific individuals. It has been widely reported that sulfonamide antimicrobials cause hypersensitivity reactions mediated by IgE or T cells. This review identifies symptoms or signs that can appear, as well as genes associated with sulfonamide hypersensitivity reactions, as sulfonamide may cause hypersensitivity in the form of uveitis, skin rash, Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), parotitis, angioedema, drug reaction with eosinophilia and systemic symptoms (DRESS), and pruritus. In addition, several genes were found to be associated with sulfonamide hypersensitivity, including HLA-A29, HLA-B12, HLA-DR7, HLA-B44, and HLA A*11:01.

CROSS-REACTIVITY TO ANTIBIOTICS: PROPOSITIONS FOR SELECTING ALTERNATIVES

OBJECTIVE

The aim: To analyze CR among antibacterials of different classes and to overcome some widespread misconceptions regarding CR between different classes of antibiotics.

PATIENTS AND METHODS

Materials and methods: The narrative review represents an assessment of the most pertinent literary sources published in English language, which dealt with the issues of cross-reactivity between individual antibiotics and different classes of these ones.

CONCLUSION

Conclusions: With a high probability of type I AR in a patient in the past, it is better to plan the treatment of patients together with an allergist / immunologist. If this probability is estimated to be low, the choice of a particular antibiotic may be based to some extent on CR data.

At-home compounding preparation of slow desensitization of elexacaftor/tezacaftor/ivacaftor for delayed hypersensitivity rash

As elexacaftor/tezacaftor/ivacaftor has proven to have robust clinical efficacy for eligible persons with cystic fibrosis, desensitization should be offered to those with maculopapular eruption hypersensitivity reactions to achieve tolerance. As presented in this case, if provided with tools for crushing and mixing the medication, a successful escalation protocol can be completed at home without coordinating the help of a compound pharmacy.

Application of pharmacovigilance tools in a case of subacute anterior angle narrowing while under furosemide exposure

Sulfonamides have been related to drug-induced acute angle closure of the eye, but scarce reports exist concerning furosemide. We describe the second case of acute chamber narrowing (ACN) during furosemide exposure. A 65-year-old man with a renal transplant presented with ACN, after 3 months of furosemide intake. Finally, the patient required a bilateral iridotomy and right lens replacement. ACN has been associated with drugs containing sulfonamide derivatives, but an evaluation with pharmacovigilance scales for adverse drug reaction (ADR)-standardised causality assessment has not been provided. We use this case to illustrate how medicines and an ADR should be evaluated and reported. The spreading of pharmacovigilance information on what should be a rare and unexpected condition related to a drug could mean that other reports emerge about ADR with this drug and regulatory agencies perform consequently, as happened with topiramate.

Bullous Erythema Multiforme Secondary to Trimethoprim-Sulfamethoxazole Use, Treated With Cyclosporine in a 91-Year-Old Male

Erythema multiforme is an acute, immune-mediated, mucocutaneous condition in which 90% of cases are triggered by infection. The second most common cause is drug-induced. It classically presents with itchy, burning targetoid lesions on the skin and mucous membranes. The lesions may be mistaken for other conditions, and thus, rapid and correct diagnosis is crucial. It is most often treated with corticosteroids, though non-responders or those with weakened immune systems may require immunomodulatory therapy. We present the case of a 91-year-old male who developed bullous erythema multiforme after treatment with trimethoprim-sulfamethoxazole who was successfully treated with cyclosporine.

Benzofuran sulfonates and small self-lipid antigens activate type II NKT cells via CD1d

Natural killer T (NKT) cells detect lipids presented by CD1d. Most studies focus on type I NKT cells that express semi-invariant αβ T cell receptors (TCR) and recognize α-galactosylceramides. However, CD1d also presents structurally distinct lipids to NKT cells expressing diverse TCRs (type II NKT cells), but our knowledge of the antigens for type II NKT cells is limited. An early study identified a nonlipidic NKT cell agonist, phenyl pentamethyldihydrobenzofuransulfonate (PPBF), which is notable for its similarity to common sulfa drugs, but its mechanism of NKT cell activation remained unknown. Here, we demonstrate that a range of pentamethylbenzofuransulfonates (PBFs), including PPBF, activate polyclonal type II NKT cells from human donors. Whereas these sulfa drug-like molecules might have acted pharmacologically on cells, here we demonstrate direct contact between TCRs and PBF-treated CD1d complexes. Further, PBF-treated CD1d tetramers identified type II NKT cell populations expressing αβTCRs and γδTCRs, including those with variable and joining region gene usage (TRAV12-1-TRAJ6) that was conserved across donors. By trapping a CD1d-type II NKT TCR complex for direct mass-spectrometric analysis, we detected molecules that allow the binding of CD1d to TCRs, finding that both selected PBF family members and short-chain sphingomyelin lipids are present in these complexes. Furthermore, the combination of PPBF and short-chain sphingomyelin enhances CD1d tetramer staining of PPBF-reactive T cell lines over either molecule alone. This study demonstrates that nonlipidic small molecules, which resemble sulfa drugs implicated in systemic hypersensitivity and drug allergy reactions, are targeted by a polyclonal population of type II NKT cells in a CD1d-restricted manner.

Sulfonamide Hypersensitivity

Sulfonamides, particularly antimicrobial sulfonamides, have been implicated as a common cause of a spectrum of hypersensitivity reactions. Immediate IgE-mediated reactions have been reported but are much less common than delayed cutaneous reactions. Delayed cutaneous reactions range from benign exanthems to severe cutaneous reactions such as Stevens Johnson syndrome, toxic epidermal necrolysis, or drug reaction with eosinophilia and systemic symptoms. Sulfonamides can be subclassified as antimicrobial sulfonamides and non-antimicrobial sulfonamides, which are also distinguished by key structural differences, resulting in very low risk of cross-reactivity between these two subclasses. Immediate and delayed skin testing and in vitro testing remain limited as options in evaluating antimicrobial sulfonamide hypersensitivity. Drug challenges continue to play an important role in the evaluation of both immediate and delayed reactions, with a growing body of evidence for the safety of direct challenges regardless of human immunodeficiency virus infection status. While numerous "desensitization" protocols have been described for the management of antimicrobial sulfonamide hypersensitivity, there is limited evidence that such procedures are successful because of an induction of tolerance.

Delabeling Delayed Drug Hypersensitivity: How Far Can You Safely Go?

Delayed immune-mediated adverse drug reactions (IM-ADRs) are defined as reactions occurring more than 6 hours after dosing. They include heterogeneous clinical phenotypes that are typically T-cell-mediated reactions with distinct mechanisms across a wide spectrum of severity from benign exanthems through to life-threatening cutaneous or organ-specific diseases. For mild reactions such as benign exanthem, considerations for delabeling are similar to immediate reactions and may include a graded or single-dose drug challenge with or without preceding skin or patch testing. Evaluation of challenging cases such as the patient who is on multiple drugs at the time a severe delayed IM-ADR occurs should prioritize clinical ascertainment of the most likely phenotype and implicated drug(s). Although not widely available and validated, procedures such as patch testing, delayed intradermal skin testing, and laboratory-based functional drug assays or genetic (human leukocyte antigen) testing may provide valuable information to further help risk stratify patients and identify the likely implicated and/or cross-reactive drug(s). The decision to use a drug challenge as a diagnostic or delabeling tool in a patient with a severe delayed IM-ADR should weigh the risk-benefit ratio, balancing the severity and priority for the treatment of the underlying, and the availability of alternative efficacious and safe treatments.

Reintroduction of Antituberculous Drugs in Patients with Antituberculous Drug-Related Drug Reaction with Eosinophilia and Systemic Symptoms

BACKGROUND

Patients who suffered drug reaction with eosinophilia and systemic symptom (DRESS) during the treatment of tuberculosis (TB) commonly experience multidrug hypersensitivity reactions resulting in limited anti-TB drug choices. Therefore, reintroduction based on a desensitization protocol may be an option to resume anti-TB medication.

OBJECTIVE

To evaluate the outcomes and safety of resuming anti-TB drugs according to reintroduction methods in patients with anti-TB drug-related DRESS.

METHODS

A retrospective cohort of patients who had experienced anti-TB drug-related severe cutaneous adverse reactions from 2011 to 2017 was established from separate 5 institutions.

RESULTS

Anti-TB medication was resumed in 27 of 29 patients with anti-TB drug-related DRESS through complete changing regimen (n = 9), reintroduction by a graded challenge (n = 5), or reintroduction using a desensitization protocol (n = 13). Nine patients completely changed their anti-TB regimen to second-line TB drugs, but only 1 (11.1%) succeeded in maintaining new anti-TB drugs. The other 8 failed to take drugs due to the occurrence of hypersensitivity reactions to the newly introduced anti-TB drugs. Two (40.0%) of 5 patients who underwent graded rechallenges successfully completed anti-TB drugs, whereas 3 (60%) failed to resume anti-TB drugs due to the recurrence of hypersensitivity reactions. In 13 patients who resumed anti-TB drugs using a desensitization protocol, no one who underwent desensitization developed recurrence of DRESS; 11 (84.6%) eventually completed anti-TB treatment and 2 eventually failed to complete anti-TB treatment due to late-onset itching and drug-induced liver injury.

CONCLUSIONS

Resuming anti-TB medication based on desensitization protocols may be a safe and effective option for those with anti-TB drug-related DRESS.

Comparison of immediate hypersensitivity reactions to preoperative antibiotics in patients labeled as penicillin allergic

BACKGROUND

Cefazolin is routinely recommended as the first-line agent for surgical antibiotic prophylaxis because it prevents more surgical site infections than second-line antibiotics. Clinicians often avoid administering cefazolin to patients who are labeled as penicillin allergic due to concerns of cross-reactivity. The aim of this study was to compare the incidence of hypersensitivity reactions between cefazolin and the second-line antibiotics vancomycin and clindamycin.

METHODS

This retrospective study included patients who were labeled as penicillin allergic and received either cefazolin, clindamycin, or vancomycin as preoperative antibiotics. The primary outcome was intraoperative hypersensitivity reactions.

RESULTS

A total of 734 surgical procedures in 690 patients were included. Fifteen immediate hypersensitivity reactions were identified. Probable hypersensitivity reactions occurred in 3 (0.9%) patients in the cefazolin group, 4 (1.4%) in the clindamycin group, and 1 (1.1%) in the vancomycin group. Seven of 8 patients reported allergies to additional medications beyond penicillin. There were seven cases of possible hypersensitivity reactions, 3 (0.9%) in the cefazolin group, 1 (1.1%) in the vancomycin group, and 3 (1.0%) in the clindamycin group.

CONCLUSION

Our data suggest that perioperative hypersensitivity reactions are uncommon in patients labeled as penicillin allergic. The frequency of immediate hypersensitivity reactions was not different between patients receiving cefazolin, clindamycin, or vancomycin. Avoiding cefazolin in patients labeled as penicillin allergic may not be warranted.

Assessment of the Frequency of Dual Allergy to Penicillins and Cefazolin: A Systematic Review and Meta-analysis

Importance

Cefazolin is the preoperative antibiotic of choice because it is safer and more efficacious than second-line alternatives. Surgical patients labeled as having penicillin allergy are less likely to prophylactically receive cefazolin and more likely to receive clindamycin or vancomycin, which results in higher rates of surgical site infections.

Objective

To examine the incidence of dual allergy to cefazolin and natural penicillins.

Data Sources

MEDLINE/PubMed, Web of Science, and Embase were searched without language restrictions for relevant articles published from database inception until July 31, 2020.

Study Selection

In this systematic review and meta-analysis, a search of MEDLINE/PubMed, Web of Science, and Embase was performed for articles published from database inception to July 31, 2020, for studies that included patients who had index allergies to a natural penicillin and were tested for tolerability to cefazolin or that included patients who had index allergies to cefazolin and were tested for tolerability to a natural penicillin. A total of 3228 studies were identified and 2911 were screened for inclusion.

Data Extraction and Synthesis

Data were independently extracted by 2 authors. Bayesian meta-analysis was used to estimate the frequency of allergic reactions.

Main Outcomes and Measures

Dual allergy to cefazolin and a natural penicillin.

Results

Seventy-seven unique studies met the eligibility criteria, yielding 6147 patients. Cefazolin allergy was identified in 44 participants with a history of penicillin allergy, resulting in a dual allergy meta-analytical frequency of 0.7% (95% credible interval [CrI], 0.1%-1.7%; I2 = 74.9%). Such frequency was lower for participants with unconfirmed (0.6%; 95% CrI, 0.1%-1.3%; I2 = 54.3%) than for those with confirmed penicillin allergy (3.0%; 95% CrI, 0.01%-17.0%; I2 = 88.2%). Thirteen studies exclusively assessed surgical patients (n = 3884), among whom 0.7% (95% CrI, 0%-3.3%; I2 = 85.5%) had confirmed allergy to cefazolin. Low heterogeneity was observed for studies of patients with unconfirmed penicillin allergy who had been exposed to perioperative cefazolin (0.1%; 95% CrI, 0.1%-0.3%; I2 = 13.1%). Penicillin allergy was confirmed in 16 participants with a history of cefazolin allergy, resulting in a meta-analytical frequency of 3.7% (95% CrI, 0.03%-13.3%; I2 = 64.4%). The frequency of penicillin allergy was 4.4% (95% CrI, 0%-23.0%; I2 = 75%) for the 8 studies that exclusively assessed surgical patients allergic to cefazolin.

Conclusions and Relevance

These findings suggest that most patients with a penicillin allergy history may safely receive cefazolin. The exception is patients with confirmed penicillin allergy in whom additional care is warranted.

Sulfonamide drugs: structure, antibacterial property, toxicity, and biophysical interactions

Sulfonamide (or sulphonamide) functional group chemistry (SN) forms the basis of several groups of drug. In vivo sulfonamides exhibit a range of pharmacological activities, such as anti-carbonic anhydrase and anti-t dihydropteroate synthetase allowing them to play a role in treating a diverse range of disease states such as diuresis, hypoglycemia, thyroiditis, inflammation, and glaucoma. Sulfamethazine (SMZ) is a commonly used sulphonamide drug in veterinary medicine that acts as an antibacterial compound to treat livestock diseases such as gastrointestinal and respiratory tract infections. Sulfadiazine (SDZ) is another frequently employed sulphonamide drug that is used in combination with the anti-malarial drug pyrimethamine to treat toxoplasmosis in warm-blooded animals. This study explores the research findings and the work behaviours of SN (SMZ and SDZ) drugs. The areas covered include SN drug structure, SN drug antibacterial activity, SN drug toxicity, and SN environmental toxicity.

Perioperative Pain Management and Opioid Stewardship: A Practical Guide

Surgical procedures are key drivers of pain development and opioid utilization globally. Various organizations have generated guidance on postoperative pain management, enhanced recovery strategies, multimodal analgesic and anesthetic techniques, and postoperative opioid prescribing. Still, comprehensive integration of these recommendations into standard practice at the institutional level remains elusive, and persistent postoperative pain and opioid use pose significant societal burdens. The multitude of guidance publications, many different healthcare providers involved in executing them, evolution of surgical technique, and complexities of perioperative care transitions all represent challenges to process improvement. This review seeks to summarize and integrate key recommendations into a "roadmap" for institutional adoption of perioperative analgesic and opioid optimization strategies. We present a brief review of applicable statistics and definitions as impetus for prioritizing both analgesia and opioid exposure in surgical quality improvement. We then review recommended modalities at each phase of perioperative care. We showcase the value of interprofessional collaboration in implementing and sustaining perioperative performance measures related to pain management and analgesic exposure, including those from the patient perspective. Surgery centers across the globe should adopt an integrated, collaborative approach to the twin goals of optimal pain management and opioid stewardship across the care continuum.

Incidence, clinical presentation, and outcomes of Pneumocystis pneumonia when utilizing Polymerase Chain Reaction-based diagnosis in patients with Hodgkin lymphoma

A Polymerase Chain Reaction-based diagnosis of Pneumocystis Pneumonia (PCP) and the need for anti-Pneumocystis prophylaxis in Hodgkin lymphoma patients receiving chemotherapy requires further investigation. This retrospective, single-center, study evaluated 506 consecutive adult patients diagnosed with Hodgkin lymphoma receiving chemotherapy between January 2006 and August 2018. The cumulative incidence of PCP 1 year after start of chemotherapy was 6.2% (95% CI 3.8-8.5%). Mortality 30 days from PCP diagnosis was 8% (n = 2) with one death attributable to PCP. Bleomycin-containing combination chemotherapy regimen was not significantly associated with a higher risk for PCP when compared to other regimens (HR = 1.59, 95% CI 0.55-4.62 p = 0.40). Anti-Pneumocystis prophylaxis was not significantly associated with a decreased incidence of PCP (HR = 0.51, 95% CI 0.15-1.71, p = 0.28). As the overall incidence is above the commonly accepted 3.5% threshold, clinicians should consider the potential value of prophylaxis. The utility of universal vs. targeted anti-Pneumocystis prophylaxis requires prospective, randomized investigation.

Efficacy and safety of quinolones for the treatment of uncomplicated urinary tract infections in women: a network meta-analysis

INTRODUCTION AND HYPOTHESIS

Uncomplicated urinary tract infection (uUTI) is defined as the presence of pathogenic organisms in the urinary tract without anatomical and functional abnormalities, is accompanied by inflammatory leukocytes and cytokines and may or may not develop clinical symptoms. The frequency of uncomplicated urinary tract infection is higher in young women. Several quinolone treatment regimens are available; however, since we do not know which is the best antibiotic regimen for the treatment of this urinary infection, we analyzed the published evidence and conducted a systematic review with network meta-analysis. The aim was to compare and hierarchize quinolones according to their efficacy and safety and to identify the best treatment for uncomplicated urinary tract infection in women through a systematic review with network meta-analysis.

METHODS

Medline, Embase, LILACS, Cochrane CENTRAL and other databases were searched for trials. Bias in the trials was assessed using the Cochrane Collaboration tool. To analyze efficacy and adverse events, for direct comparisons, we obtained risk ratios and 95% confidence intervals by applying a fixed-effects model using tau² and Q² tests to calculate the heterogeneity. For the network meta-analysis, we analyzed the indirect comparisons by Bucher's method.

RESULTS

We included 18 trials (8765 women). For premenopausal women, ofloxacin had a 57% probability of achieving remission but an 83% frequency of adverse events. For postmenopausal women, ofloxacin was 82% more effective for remission, with a 49% frequency of adverse events, compared with other types of quinolones.

CONCLUSIONS

Compared with other quinolones, ofloxacin 200 mg once daily for a treatment duration < 3 days provides the highest clinical and bacteriological remission rates with the lowest relapse and resistance rates for the treatment of women with uUTIs. However, additional trials are needed to confirm our findings, especially when the treatment duration exceeds 3 days.

Addressing the epidemic of antibiotic "allergy" over-diagnosis

OBJECTIVE

An epidemic of antibiotic allergy is occurring.

DATA SOURCES

Articles published since 2008.

STUDY SELECTIONS

Articles on antibiotic allergy and stewardship.

RESULTS

A number of overlapping factors contribute. The most important factor is antibiotic overuse. Antibiotics are commonly used in situations in which no antibiotics are indicated. Thirty percent to 50% of ambulatory antibiotic use may be inappropriate. The duration of indicated antibiotic use is often excessive, which leads to more side effects. All antibiotic use can result in adverse reactions, and a fraction of these will be dutifully recorded as an allergy in the electronic health record (EHR). Most EHRs are not well structured to accurately convey information on expected side effects that have occurred, metabolic or other contraindications, dose-related or situational toxicities, personal preferences, clinically significant immunologically mediated hypersensitivity, and other reasons a particular patient may not want or should not be given a specific drug or type of drug in the future. As populations age, their accumulated baggage of reported antibiotic allergies increase. Suspected antibiotic allergy is rarely confirmed with appropriate testing or rechallenge. Patients then receive suboptimal antibiotic therapy and experience more side effects, treatment failures, and serious antibiotic-resistant infections. Reporting an antibiotic allergy in the EHR is nominally done to improve patient safety, but unfortunately, this is often not the actual result.

CONCLUSION

Audit and feedback, to help ensure adherence to Choosing Wisely recommendations and good antibiotic stewardship practices, can help reduce inappropriate antibiotic use. Restructuring EHRs to facilitate correct drug intolerance reporting, along with active antibiotic allergy delabeling programs, can help stem this epidemic.