Repeated idiopathic anaphylaxis caused by povidone

Excipient induced allergies in oral medications: unravelling the covert threat - a systematic review

Excipients have been identified as 'inert' substances that often enhance the non-pharmacological aspects of a medication. However, recent clinical evidence elucidates their potential in inducing anaphylaxis and indicates that they are often overlooked as potential allergens in routine clinical practice. The aim of the study was to assimilate published evidence on excipient-induced allergies associated with the use of oral medications and to underline their potential as potent allergens. A systematic literature search of MEDLINE, EMBASE and International Pharmaceutical Abstracts databases was performed for case reports published from inception to June 2024. Studies were excluded if they were animal and laboratory studies or not published in English, full-text articles were unavailable, and they lacked essential information. This systematic review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Polyethylene glycol was the most prevalent allergenic excipient, followed by colouring agents. Clinical manifestations exhibited wide variability ranging from mild to life-threatening reactions, and the most common presentations were urticaria and angioedema. Most patients recovered spontaneously after withdrawal of the offending agent with less than half necessitating additional drug interventions and only a single instance of reported fatality, which cannot be attributed to the excipient alone. Despite being labelled as inert, excipients pose a significant threat for the development of allergic reactions. Simple measures such as increased awareness among patients and healthcare professionals, comprehensive history taking, reviewing medication compositions and improved patient awareness regarding potentially allergenic excipients can aid in avoiding these readily preventable reactions.

Formulation and evaluation of PVA-based composite hydrogels: physicochemical, leachables, and in vitro immunogenicity studies

This study explores the formulation and characterization of poly(vinyl alcohol) (PVA)-based composite hydrogels synthesized through solid-state crosslinking. Comprehensive assessments were conducted on their physicochemical properties, leachables, and immunogenicity. Swelling experiments demonstrated that the incorporation of poly(vinylpyrrolidone) (PVP) enhanced water retention, while chitosan had a minimal effect on swelling behavior. Qualitative analysis of leachables identified water-soluble components, including dehydrated PVA and PVP. Fourier-transform infrared (FTIR) spectroscopy confirmed the formation of ester bonds and indicated increased hydrogen bonding post-crosslinking. Thermal stability was validated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), with decomposition observed at 320-330 °C. X-ray diffraction (XRD) analysis revealed enhanced crystallinity following crosslinking. Solid-state nuclear magnetic resonance (NMR) further confirmed chemical changes consistent with the results from other characterization techniques. In vitro assays using DC2.4 mouse dendritic cells showed that hydrogel extracts inhibited cell proliferation without causing cytotoxicity or triggering significant immune responses. These findings highlight the hydrogels' biocompatibility and stability, supporting their potential for biomedical applications.

Anaphylaxis: Advances in the Past 10 Years

In the past 10 years, anaphylaxis has grown into its own special area of study within Allergy-Immunology, both at the bench and at the bedside. This review focuses on some of the most clinically relevant advances over the past decade. These include simplified and more inclusive diagnostic criteria for adults and children, uniform definition of biphasic anaphylaxis, and improved systems for objective severity grading. Studies reported in the past decade have led to improved understanding of normal and abnormal regulation of mast cell function, translating into better diagnostic and therapeutic approaches to patients with anaphylaxis. Research has provided improved recognition and treatment of mast cell disorders and has identified a new condition, hereditary α-tryptasemia, that may impact anaphylactic syndromes. We have learned to recognize new causes (α-gal), new pathways (Mas-related G protein-coupled receptor-X2), and many risk factors for severe anaphylaxis. The stability of epinephrine in autoinjectors was reported to be very good for several years after the labeled expiry date, and it can tolerate freezing and thawing. Repeated and prolonged exposure to excessive heat leads to degradation of epinephrine activity. New treatments to prevent severe anaphylaxis have been described, using new ways to block the IgE receptor or modulate intracellular signaling pathways.

Diagnostic Value of Oral Provocation Tests in Drug Hypersensitivity Reactions Induced by Nonsteroidal Anti-Inflammatory Drugs and Paracetamol

Oral drug provocation tests (DPT) are the basic diagnostic tool for the detection of hypersensitivity to non-opioid analgesics and for selecting a safe alternative for a patient. They are of great practical importance due to their common use, but the data on the follow-up of patients after negative DPT are still very scarce. We examined the further fate of 164 such adult patients after negative NSAID or paracetamol tests and analyzed which excipients in the studied drugs they could be exposed to after the diagnostic workup. A structured medical interview was performed 32.9 months (mean) after the provocation tests. Of the 164 patients, 131 (79.9%) retook the tested drug and 12 developed another hypersensitivity reaction, giving the estimated negative predictive value of 90.8%. These reactions were induced by acetylsalicylic acid, paracetamol, meloxicam, and diclofenac, and were clinically similar to the initial ones (most commonly urticaria and angioedema). There are 93 generics of these drugs on the local market, containing a total of 33 excipients for which hypersensitivity reactions have been reported. All available generics contain such excipients. Thirty-one patients (20.1%) did not take the previously tested drug again, most often because it was not needed or because they were afraid of another reaction. DPT with analgesics has a high diagnostic performance. A minority of patients had relapsed after reexposure. One of the underestimated reasons for this may be drug excipients provoking a reaction, so it is advisable to use exactly the same medical product that has been negatively tested. Many patients avoid reexposure to a given drug, despite negative tests, therefore very reliable patient education in connection with DPT is highly needed.

Anaphylaxis to Excipients in Current Clinical Practice: Evaluation and Management

Excipients are the inactive ingredients in a drug or product that help to stabilize, preserve, or enhance the pharmacokinetics and bioavailability of the active ingredients. Excipient allergy is rare and hence often missed or misdiagnosed due to lack of awareness of the need to carefully review all drug ingredients. For the patient, excipient allergy can be frightening and potentially disruptive to health care delivery. This narrative review provides a clinically oriented, international, collaborative perspective on excipient allergy testing, management of future health care safety, limitations in our testing modalities, and barriers to optimal care.