Contemporary issues in anaphylaxis and the evolution of epinephrine autoinjectors: What will the future bring?

Frequencies and predictors of subcutaneous and intraosseous injection with 4 epinephrine autoinjector devices

BACKGROUND

To prevent anaphylaxis-associated illness, intramuscular epinephrine injection is recommended. Subcutaneous injection may reduce efficacy, and intraosseous injection promotes morbidity. A few studies suggested that commercially available thigh epinephrine autoinjectors (EAIs) may induce subcutaneous/intraosseous injection in some adults.

OBJECTIVE

To estimate the subcutaneous/intraosseous-injection rates of 4 EAIs by comparing their needle lengths with the ultrasound-measured skin-to-muscle depth and skin-to-bone depth of the midthigh of adults with allergic diseases in a cross-sectional study and to determine patient factors that predict subcutaneous EAI injection.

METHODS

Thigh ultrasound was conducted in a convenience-recruited cohort with minimal and maximal compression to estimate the effect of EAI-induced compression. Subcutaneous/intraosseous-injection rates were estimated for Anapen (BioProject), EpiPen (Mylan), Jext (ALK), and Emerade (Medeca). Multivariate analyses for subcutaneous-injection risk were conducted with age, male/female sex, abdominal and thigh circumferences, and upper-arm skinfold thickness.

RESULTS

A total of 68 patients were recruited. Compression thinned the subcutaneous tissue and muscle by 1 and 9 mm, respectively, on average. Projected subcutaneous-injection rates with/without compression were high for Anapen (65%-66%), moderate for EpiPen and Jext (29%-38%), and lowest for Emerade (13%-21%). Compression introduced a small intraosseous-injection risk with Emerade (4%). Female sex predicted subcutaneous injection (odds ratio, 1.3-2.0; all P < .001). Depending on the EAI, 29% to 97% of women and 0% to 41% of men would be injected subcutaneously. Older men were at risk of intraosseous Emerade injection. Obesity-related variables predicted subcutaneous injection poorly.

CONCLUSION

Anapen was associated with high subcutaneous-injection rates. EpiPen and Jext were projected to provide intramuscular injection in all men without risk of intraosseous injection. Emerade yielded the lowest subcutaneous-injection rates in women. Compression largely affected the muscle.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02886468.

A 13.2 mg epinephrine intranasal spray demonstrates comparable pharmacokinetics, pharmacodynamics, and safety to a 0.3 mg epinephrine autoinjector

Background

Recent acute anaphylaxis guideline updates have identified remaining unmet needs based on currently available therapeutic options as a critical focus.

Objective

We compared the pharmacokinetic, pharmacodynamic, safety, and tolerability profiles of intranasal epinephrine with intramuscular epinephrine administered by autoinjector and manual syringe.

Methods

An open-label, 3-period crossover study was conducted in 116 healthy adult volunteers to assess the bioavailability of a single 13.2 mg intranasal dose of epinephrine compared to a 0.3 mg intramuscular autoinjector and a 0.5 mg manual syringe. Patients with epinephrine concentrations of 50, 100, and 200 pg/mL at 10, 20, 30, and 60 minutes after dosing were also evaluated.

Results

Pharmacokinetic parameters for the 13.2 mg intranasal dose exceeded those of the 0.3 mg autoinjector with a rapid and higher maximum observed concentration (intranasal, 429.4 pg/mL; autoinjector, 328.6 pg/mL) and greater systemic exposure (AUC0-360; intranasal, 39,060 pg∙min/mL; autoinjector, 17,440 pg∙min/mL). Similar results were observed compared to the 0.5 mg manual syringe. Pharmacokinetic parameters for opposite-nostril and same-nostril dosing were higher than both intramuscular doses, except time to reach maximum observed concentration, which was bracketed between the 2 intramuscular doses (intranasal opposite and same nostril, 20 minutes; autoinjector, 14.9 minutes; manual syringe, 45 minutes). Similar effects on blood pressure and heart rate were observed for intranasal and autoinjector administration. Intranasal epinephrine was safe and well tolerated. No serious or unexpected adverse events were reported, confirming results from earlier clinical studies.

Conclusions

Bidose epinephrine spray addresses the unmet medical and patient needs for a needle-free, convenient, and effective dose-delivery system for self-administration of epinephrine that is as good as or better than the 0.3 mg autoinjector.

Innovations in the treatment of anaphylaxis: A review of recent data

PURPOSE OF REVIEW

The current standard of first-line emergency treatment of anaphylaxis is intramuscular (IM) epinephrine, mostly administered through epinephrine autoinjector (EAI) in the outpatient setting. However, undercarriage and underuse of EAIs are common, and delayed epinephrine use is associated with increased morbidity and mortality. Patients, caregivers, and healthcare professionals have expressed a strong desire for small, needle-free devices and products that would offer improved carriage, ease of use, and more convenient, less invasive routes of epinephrine administration. Novel mechanisms of epinephrine administration are under investigation to help address several recognized EAI limitations. This review explores innovative nasal and oral products under investigation for the outpatient emergency treatment of anaphylaxis.

FINDINGS

Human studies of epinephrine administered through nasal epinephrine spray, a nasal powder spray, and a sublingual film have been conducted. Data from these studies indicate promising pharmacokinetic results comparable to those of the standard of outpatient emergency care (0.3-mg EAI) and syringe and needle IM epinephrine administration. Several products have shown maximum plasma concentration values higher than those of the 0.3-mg EAI and manual IM injection, although it remains unclear whether this has clinical relevancy in patient outcomes. Generally, these modalities show comparable time to maximum concentrations. Pharmacodynamic changes observed with these products are comparable to or more robust than those seen with EAI and manual IM injection.

SUMMARY

Given comparable or superior pharmacokinetic and pharmacodynamic results and safety of innovative epinephrine therapies to those of current standards of care, US Food and Drug Administration approval of these products may help address numerous barriers that EAIs present. The ease of use and carriage and favorable safety profiles of needle-free treatments may make them an attractive alternative to patients and caregivers, potentially addressing injection fears, needle-based safety risks, and other reasons for lack of or delayed use.

Epinephrine autoinjectors: individualizing device and dosage to optimize anaphylaxis management in the community setting

Background: Anaphylaxis is the most severe manifestation of a systemic allergic reaction, and, in the community setting, the immediate administration of an epinephrine autoinjector (EAI) can be life-saving. Physicians are tasked with selecting the most appropriate EAI for each individual and counseling patients and/or their caregivers to maximize the likelihood of successful deployment of the EAI. Objective: To offer an evidence-based expert clinical perspective on how physicians might best tailor EAI selection to their patients with anaphylaxis. Methods: A group of eight adult and pediatric allergists with expertise in anaphylaxis management reviewed and assessed the published data and guidelines on anaphylaxis management and EAI device selection. Results: Personalized EAI selection is influenced by intrinsic individual factors, extrinsic factors such as the properties of the individual EAI (e.g., dose, needle length, overall design) as well as cost and coverage. The number and the variety of EAIs available have expanded in most jurisdictions in recent years, which provide a greater diversity of options to meet the characteristics and needs of patients with anaphylaxis. Conclusion: There currently are no EAIs with customizable dose and needle length. Although precise personalization of each patient's EAI remains an optimistic future aspiration, careful consideration of all variables when prescribing EAIs can support optimal management of anaphylaxis.

Anaphylaxis viewed by experts: unmet needs

PURPOSE OF REVIEW

The purpose of the review is to identify unmet needs in the management of anaphylaxis, covering aspects such as epidemiology, diagnosis, treatment and prevention.

RECENT FINDINGS

Redefinition of clinical diagnostic criteria may allow a better identification of anaphylaxis. International diagnostic coding system improvement will be major step for future policies and epidemiological studies. Digital health can aid in managing anaphylaxis.

SUMMARY

Anaphylaxis is a medical emergency; current data show that frequently identification of the reaction, acute and long-term management, are not optimal. Therefore, there is a need to implement strategies to improve the situation. This review has identified unmet needs in anaphylaxis regarding aspects such as epidemiology, severity scoring, definition and diagnostic criteria, anaphylaxis in infants and toddlers, cofactors, biomarkers, long-term management, undertreatment and availability of epinephrine autoinjectors. Strategies focused on education, legislation, digital health and research are proposed.

Allergic fungal airways disease (AFAD): an under-recognised asthma endotype

The term allergic fungal airways disease has a liberal definition based on IgE sensitisation to thermotolerant fungi and evidence of fungal-related lung damage. It arose from a body of work looking into the role of fungi in asthma. Historically fungi were considered a rare complication of asthma, exemplified by allergic bronchopulmonary aspergillosis; however, there is a significant proportion of individuals with Aspergillus fumigatus sensitisation who do not meet these criteria, who are at high risk for the development of lung damage. The fungi that play a role in asthma can be divided into two groups; those that can grow at body temperature referred to as thermotolerant, which are capable of both infection and allergy, and those that cannot but can still act as allergens in IgE sensitised individuals. Sensitisation to thermotolerant filamentous fungi (Aspergillus and Penicillium), and not non-thermotolerant fungi (Alternaria and Cladosporium) is associated with lower lung function and radiological abnormalities (bronchiectasis, tree-in-bud, fleeting shadows, collapse/consolidation and fibrosis). For antifungals to play a role in treatment, the focus should be on fungi capable of growing in the airways thereby causing a persistent chronic allergenic stimulus and releasing tissue damaging proteases and other enzymes which may disrupt the airway epithelial barrier and cause mucosal damage and airway remodelling. All patients with IgE sensitisation to thermotolerant fungi in the context of asthma and other airway disease are at risk of progressive lung damage, and as such should be monitored closely.

Allergic Broncho-Pulmonary Aspergillosis

Allergic broncho-pulmonary aspergillosis (ABPA) is an immunologically mediated lung disease that usually occurs in people with a diagnosis of asthma or cystic fibrosis. It is a noninvasive lung disease caused by colonization of the airways with Aspergillus fumigatus. In people who are susceptible, Aspergillus leads to an exaggerated immune response and ultimately pulmonary inflammation and lung damage. Patients with ABPA typically present with poorly controlled asthma, recurrent pulmonary infiltrates, and bronchiectasis. Diagnosis of ABPA is established based on a combination of clinical manifestations as well as laboratory and radiological evaluations. Delay in diagnosis can result in airway destruction and pulmonary fibrosis, which may result in significant morbidity and mortality. This article discusses the clinical characteristics, diagnosis, and management of patients with ABPA. It aims to serve as a tool for pediatricians to aid in early recognition of this debilitating disease and consider referral, facilitating early diagnosis and treatment. [Pediatr Ann. 2021;50(5):e214-e221.].

Clinical characteristics of allergic bronchopulmonary aspergillosis in patients with and without bronchiectasis

OBJECTIVE

Allergic bronchopulmonary aspergillosis (ABPA) is classified radiologically as serologic ABPA (ABPA-S) or ABPA with central bronchiectasis (ABPA-CB). This retrospective case series study aimed to describe and compare the clinical characteristics of both forms of ABPA.

METHODS

Patients with ABPA treated in the hospital between February 2011 and June 2019 were enrolled and were divided into ABPA-S and ABPA-CB groups based on whether their cases were complicated with central bronchiectasis. Demographic data, symptoms, laboratory values, comorbidities, and image findings were collected. ABPA-S patients were followed up retrospectively through medical records.

RESULTS

Ninety-three (93) patients were enrolled, including 74 ABPA-CB patients and 19 ABPA-S patients. The most common predisposing condition was asthma (36.6%), with a median course of 30 years (IQR 13-42.5) prior to ABPA diagnosis. Patients of 54.8% had been misdiagnosed, with ABPA-S more likely than ABPA-CB to have been misdiagnosed as asthma (p < 0.01). Obstructive ventilation dysfunction and mixed ventilation dysfunction were found in 21 patients (22.6%) and 16 patients (17.2%), respectively. Compared with ABPA-S, ABPA-CB had a higher median blood eosinophil count (880 vs. 700 cells/μl), serum IgE (2957 vs. 2616 IU/ml), and Aspergillus fumigatus specific-IgE (20.6 vs. 7.31 kUA/L), although these findings were not statistically significant. Three ABPA-S patients developed bronchiectasis during follow-up and experienced relapses more than twice.

CONCLUSIONS

Our findings suggested that the clinical characteristics between ABPA-CB and ABPA-S were mostly similar. ABPA-S had a relatively lower immunological activity level than ABPA-CB but was still immunologically active and could develop bronchiectasis.

Ideal body position for epinephrine autoinjector administration

Background: Epinephrine is the first-line therapy for patients with anaphylaxis, and intramuscular (IM) delivery is shown to be superior to subcutaneous (SC) delivery. There currently is no consensus on the ideal body position for epinephrine autoinjector (EAI) administration. Objective: We designed this study to investigate whether SC tissue depth (SCTD) is affected by body position (e.g., standing, sitting, supine), which can potentially impact delivery of EAI into the IM space. Methods: Volunteer adults (ages ≥ 18 years) from a military medical treatment facility in the United States were recruited to participate in this study. SCTD of the vastus lateralis was measured via ultrasound at standing, sitting, and supine body positions. Subjects' age, sex, and body mass index (BMI) were collected. Statistical analysis was performed to compare average SCTD between body positions, sex, and BMI. Results: An analysis of variance of 51 participants (33 men and 18 women) did not reveal statistically significant difference in SCTD among standing, sitting, and supine body positions. It did show a significantly greater SCTD in women than in men (2.72 ± 1.36 cm versus 1.10 ± 0.38 cm; p < 0.001). There was no significant association observed between BMI and SCTD in this study. Conclusion: Body position did not seem to significantly change the distance between skin and thigh muscle in adults. This would suggest that there might not be an ideal body position for EAI administration. Therefore, in case of anaphylaxis, prompt administration of epinephrine is recommended at any position.

Emerging Therapies in Anaphylaxis: Alternatives to Intramuscular Administration of Epinephrine

PURPOSE OF REVIEW

Anaphylaxis is a severe, life-threatening, systemic allergic reaction that should be recognized and treated promptly. Intramuscular (IM) epinephrine is the first-line treatment for anaphylaxis and there are no absolute contraindications to its use. Despite its established track record of efficacy and safety, physicians and patients face barriers in the recognition and treatment of anaphylaxis, including the maintenance and appropriate use of epinephrine auto-injectors. This has led to investigation into potential alternatives to IM epinephrine administration in anaphylaxis.

RECENT FINDINGS

This review investigates the current standard of care in the treatment of anaphylaxis, barriers to IM epinephrine use, and alternative therapies under investigation for administration in anaphylaxis. Alternative routes under investigation include intranasal, sublingual, inhaled, and needle-free intramuscular administration of epinephrine. There are currently numerous investigational alternatives to IM epinephrine therapy which could hold promise as future effective treatments in the emergent management of anaphylaxis.

Self-injectable epinephrine: doctors' attitude and patients' adherence in real-life

PURPOSE OF REVIEW

Epinephrine is the only life-saving treatment of anaphylaxis. Prescription and administration rates of self-injectable epinephrine are generally low. It is unclear whether this is because of availability, low prescription rates, fear of using epinephrine, or a combination of these issues.

RECENT FINDINGS

This review focuses on what self-injectable epinephrine devices (SIED), such as auto-injectors and prefilled syringes, are preferred by patients and healthcare professionals (HCP). Our findings suggest that a device's ease to use, proper and frequent training on its operability, and availability have an impact on preferences and adherence to treatment with SIEDs. After prescribing a patient with a SIED, clinicians should emphasize its use in anaphylaxis, educate patients/caregivers to identify anaphylaxis and on how to use the SIED, and encourage constant practicing with training devices.

SUMMARY

Epinephrine is the sole recommended anaphylaxis treatment and SIEDs are of critical usefulness in the community setting. Further studying of these devices is needed to optimize education for HCPs and patients and their accessibility to SIEDs.

Epinephrine Auto-Injectors for Anaphylaxis Treatment in the School Setting: A Discussion Paper

Introduction:Anaphylaxis is a serious, life-threatening systemic allergic reaction that may occur in individuals not previously diagnosed with an allergy. Emergency first-line treatment of choice for acute anaphylaxis is intramuscular administration of epinephrine via an auto-injector. In the school setting, students with known allergies typically keep or carry an epinephrine auto-injector (EAI). For students who do not have a known allergy or for those whose personal EAIs are unavailable, an anaphylactic event could have serious adverse outcomes if an EAI is not available via an undesignated stock supply in the school.

Methods:We searched the published literature from 2000 through 2018 in CINAHL, MEDLINE, and PubMed using the following search terms: anaphylaxis, school setting, epinephrine auto-injector, and food allergies. Throughout this article, undesignated stock EAIs, stock EAIs, EAI stock, and open-order EAIs are used interchangeably.

Conclusion:Anaphylaxis is increasing worldwide as the incidence of food allergies increases. Although stock EAIs for students in schools can have important benefits, the availability of EAIs in the school setting is limited. Barriers to undesignated stock EAIs include the lengthy administrative process for developing school policies and protocols; gaps in nurses' self-perceived knowledge versus objective knowledge on the topic of anaphylaxis; limited resources in many school districts; and complex role demands, lack of confidence in trained staff, or insufficient school nurse staffing. It is important that epinephrine be readily available in schools. Barriers to facilitating stock EAIs include those that can be addressed directly by nurses and those that may require policy changes. Nurses, particularly those working in school settings or pediatrics, could take the lead in discussions about the benefits of stock EAIs in schools, advocating for policy changes as warranted. Fully informed nurses can be better prepared to serve as advocates in ensuring that EAIs are available in school settings.

Epinephrine auto-injector needle lengths: Can both subcutaneous and periosteal/intraosseous injection be avoided?

BACKGROUND

Epinephrine should be administered intramuscularly in the anterolateral aspect of the thigh. The length of the epinephrine auto-injector (EAI) needle should ensure intramuscular injection.

OBJECTIVE

To discuss suitable EAI needle lengths based on ultrasound measurements related to weight.

METHODS

The skin-to-muscle distance (STMD) and skin-to-bone distance (STBD) were measured by ultrasound in the mid-third of the anterolateral area of the right thigh when applying high pressure (8 lb; high-pressure EAI [HPEAI]) or low pressure (low-pressure EAI [LPEAI]) on the ultrasound probe. The study included 302 children and adolescents and 99 adults. The maximum and minimum STMD and the maximum and minimum STBD were estimated.

RESULTS

Using HPEAIs, the risk of periosteal or intraosseous penetration was 32% in children weighing less than 15 kg. The risk of subcutaneous injection was 12% in adolescents and 33% in adults. With LPEAIs, there was no risk of periosteal or intraosseous injection and the risk of subcutaneous injections in adolescents and adults was lower at 2% and 10%, respectively. A new EAI for injection in small children would have no risk of periosteal or intraosseous injection but would have 71% chance of subcutaneous deposit of epinephrine.

CONCLUSION

Common HPEAIs have a high risk of periosteal or intraosseous penetration in children and subcutaneous injections in overweight and obese adults. LPEAIs have some risk of subcutaneous injection in adults. HPEAIs with 0.1 mg of epinephrine and shorter needles have no risk of periosteal or intraosseous injection but have a high risk of subcutaneous deposit. For adult or overweight or obese patients, HPEAIs and LPEAIs should have longer needles. Future studies should focus on triggering pressures and variations in needle length.

Allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is caused by an exaggerated T(H)2 response to the ubiquitous mold Aspergillus fumigatus. ABPA develops in a small fraction of patients with cystic fibrosis and asthma, suggesting that intrinsic host defects play a major role in disease susceptibility. This article reviews current understanding of the immunopathology, clinical and laboratory findings, and diagnosis and management of ABPA. It highlights clinical and laboratory clues to differentiate ABPA from cystic fibrosis and asthma, which are challenging given clinical and serologic similarities. A practical diagnostic algorithm and management scheme to aid in the treatment of these patients is outlined.

Noninvasive pulmonary Aspergillus infections

Aspergillus can cause several forms of pulmonary disease ranging from colonization to invasive aspergillosis and largely depends on the underlying lung and immune function of the host. This article reviews the clinical presentation, diagnosis, pathogenesis, and treatment of noninvasive forms of Aspergillus infection, including allergic bronchopulmonary aspergillosis (ABPA), aspergilloma, and chronic pulmonary aspergillosis (CPA). ABPA is caused by a hypersensitivity reaction to Aspergillus species and is most commonly seen in patients who have asthma or cystic fibrosis. Aspergillomas, or fungus balls, can develop in previous areas of cavitary lung disease, most commonly from tuberculosis. CPA has also been termed semi-invasive aspergillosis and usually occurs in patients who have underlying lung disease or mild immunosuppression.