Opioid toxicity: histamine, hypersensitivity, and MRGPRX2.

Insights into the pathophysiology of many non-immune-mediated drug reactions referred to as toxicities, sensitivities, intolerances, or pseudoallergies have resulted from research identifying the mastocyte-related G-protein-coupled receptor (GPCR) member X2 (MRGPRX2), a human mast cell receptor mediating adverse reactions without the involvement of antibody priming. Opioid-induced degranulation of mast cells, particularly morphine, provoking release of histamine and other preformed mediators and causing hemodynamic and cutaneous changes seen as flushing, headache and wheal and flare reactions in the skin, is an example of results of MRGPRX2 activation. Opioids including morphine, codeine, dextromethorphan and metazocine as well as endogenous prodynorphin opioid peptides activate MRGPRX2 at concentrations causing mast cell degranulation.

Adverse reactions to targeted and non-targeted chemotherapeutic drugs with emphasis on hypersensitivity responses and the invasive metastatic switch.

More than 100 drugs are used to treat the many different cancers. They can be divided into agents with relatively broad, non-targeted specificity and targeted drugs developed on the basis of a more refined understanding of individual cancers and directed at specific molecular targets on different cancer cells. Individual drugs in both groups have been classified on the basis of their mechanism of action in killing cancer cells.

Antibiotic allergy: immunochemical and clinical considerations.

Antibiotics are among the most widely and heavily prescribed drugs, but despite this, allergic reactions to most groups of antibiotics are relatively uncommon-especially when compared with the number and frequency of type 1 hypersensitivity responses to the beta-lactams (ie, penicillins, cephalosporins, and, to a lesser extent, carbopenems). Still, there remains a steady flow of reports of allergic reactions to some topically used antibiotics (eg, rifamycin SV and bacitracin). Moreover, aminoglycosides (eg, neomycin and gramicidin) may be implicated more often than previously suspected.

Immunoglobulin E binding determinants on beta-lactam drugs.

Purpose Of Review: Allergies to penicillins and cephalosporins remain an important clinical problem, but structural and immunochemical knowledge of the allergenic structures involved has tended to lag behind the heavy usage, consequent adverse reactions and introduction of new therapeutic members of these two families of antibiotics. Evidence of the increasing incidence of reactions to cephalosporins and to "minor" determinants of the beta-lactams is accumulating. Also, although numerous reports detail unique allergic recognitions of individual members of the two families, particularly the cephalosporins, information remains predominantly clinical.