Definitions and mechanisms of drug hypersensitivity

Genetics of Severe Cutaneous Adverse Reactions

Severe cutaneous adverse reactions (SCARs) including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS) are T cells-mediated life-threatening immune reactions, most commonly induced by drug. The last decade has seen significant progress in SCARs research. Recent studies have unveiled the pathogenesis of SCARs involved in susceptible genes, including human leukocyte antigens (HLA) and drugs-T cell receptor (TCR) interaction that may trigger T cell activation with downstream immune signaling of cytokines/chemokines and specific cytotoxic proteins releases. Advances in identification of multiple genetic alleles associated with specific drugs related SCARS in different populations is an important breakthrough in recent years for prevention of SCARs. This article summarized the findings on genetic factors related to SJS/TEN, especially for HLA.

Spontaneous reports of hypersensitivity adverse drug reactions in Portugal: a retrospective analysis

BACKGROUND

Hypersensitivity adverse drug reactions (ADRs) are usually serious, unpredictable, and associated with high morbidity and mortality. This study describes cases of hypersensitivity ADRs spontaneously reported in Central Portugal.

METHODS

Spontaneous reports (SRs) of ADRs received between 2010 and 2017 were reviewed to identify cases of hypersensitivity reactions, using a Standardized MedDRA Query (SMQ). Seriousness, expectedness, and causality were assessed. Descriptive statistics were used to analyze data.

RESULTS

Among 2050 SRs, 598 (29.2%) contained 726 hypersensitivity ADRs: 657 (90.5%) serious, 569 (78.4%) unexpected, and 469 (64.6%) certainly related to drug exposure. Anaphylactic reactions (n = 93; 12.8%), rash maculopapular (n = 82; 11.3%), rash (n = 67; 9.2%) and DRESS (n = 54; 7.4%) were the most common reactions. Frequently implicated drug classes comprised antibiotics (n = 150; 23.0%), antineoplastic agents (n = 124; 19.0%), antigout preparations (n = 54; 8.3%), and anti-inflammatories (n = 44; 6.8%). Top-causative drugs were allopurinol (n = 54; 8.3%), docetaxel (n = 46; 7.1%), and trimethoprim/sulfamethoxazole (n = 26; 4.0%).

CONCLUSIONS

Most hypersensitivity ADRs were serious, unexpected, and with strong causal relationship with suspected drugs. Allopurinol was the top-causative drug. Besides antibiotics and anti-inflammatories, antineoplastic agents were frequently cited. These results deserve further investigation.

Angiotensin-Converting Enzyme Inhibitors Induce Cough

Angiotensin-converting enzyme inhibitors (ACE-I) are widely used in diseases, such as hypertension, congestive heart failure, and myocardial infarction. Although these drugs are well tolerated, one out of five patients discontinues ACE-I due to drug side effects, mainly chronic cough. However, the pathogenesis of ACE-I-induced cough remains controversial and requires further study. In this review, the mechanisms that are suggested in ACE-I-induced cough pathophysiology will be discussed in detail in light of the current literature.

Drug metabolism and hypersensitivity reactions to drugs

PURPOSE OF REVIEW

The aim of the present review was to discuss recent advances supporting a role of drug metabolism, and particularly of the generation of reactive metabolites, in hypersensitivity reactions to drugs.

RECENT FINDINGS

The development of novel mass-spectrometry procedures has allowed the identification of reactive metabolites from drugs known to be involved in hypersensitivity reactions, including amoxicillin and nonsteroidal antiinflammatory drugs such as aspirin, diclofenac or metamizole. Recent studies demonstrated that reactive metabolites may efficiently bind plasma proteins, thus suggesting that drug metabolites, rather than - or in addition to - parent drugs, may elicit an immune response. As drug metabolic profiles are often determined by variability in the genes coding for drug-metabolizing enzymes, it is conceivable that an altered drug metabolism may predispose to the generation of reactive drug metabolites and hence to hypersensitivity reactions. These findings support the potential for the use of pharmacogenomics tests in hypersensitivity (type B) adverse reactions, in addition to the well known utility of these tests in type A adverse reactions.

SUMMARY

Growing evidence supports a link between genetically determined drug metabolism, altered metabolic profiles, generation of highly reactive metabolites and haptenization. Additional research is required to developing robust biomarkers for drug-induced hypersensitivity reactions.

Pharmacogenomics of antimicrobial agents

Antimicrobial efficacy and toxicity varies between individuals owing to multiple factors. Genetic variants that affect drug-metabolizing enzymes may influence antimicrobial pharmacokinetics and pharmacodynamics, thereby determining efficacy and/or toxicity. In addition, many severe immune-mediated reactions have been associated with HLA class I and class II genes. In the last two decades, understanding of pharmacogenomic factors that influence antimicrobial efficacy and toxicity has rapidly evolved, leading to translational success such as the routine use of HLA-B*57:01 screening to prevent abacavir hypersensitivity reactions. This article examines recent advances in the field of antimicrobial pharmacogenomics that potentially affect treatment efficacy and toxicity, and challenges that exist between pharmacogenomic discovery and translation into clinical use.

Acute generalized exanthematous pustulosis induced by piroxicam: a case report

Acute generalized exanthematous pustulosis (AGEP) is a severe adverse cutaneous reaction characterized by an acute episode of sterile pustules over erythematous-edematous skin. The main triggering drugs are antibiotics, mainly beta-lactam and macrolides. Non-steroid anti-inflammatory drugs may rarely be responsible. We describe a case of a woman with AGEP, who presented with generalized pustulosis lesions after the use of piroxicam for renal colic. The diagnosis was confirmed by the clinical and histological correlations and the dermatosis resolved after withdrawal of the drug.