Call for worldwide withdrawal of benzalkonium chloride from nebulizer solutions

Anaphylaxis to intravenous paracetamol containing povidone. A case report and narrative review of excipient allergy related to anaesthesia

Investigation of intraoperative anaphylaxis includes the exclusion of potential trigger agents the individual was exposed to within a plausible interval preceding the reaction. Occasionally, none of these agents will test positive. In this situation it is important to consider that excipients may be responsible for anaphylaxis, that the dilutions prepared to test the medication may not contain an appropriate concentration of the excipient to induce a positive skin reaction, or if an alternative formulation of the medication is tested, it may not contain the culprit excipient. This case describes a patient, who previously experienced an anaphylactic reaction to Betadine® (Sanofi-Aventis Australia Pty Ltd, North Ryde BC, NSW) experiencing anaphylaxis in the recovery period after general anaesthesia where Betadine was avoided. The recently administered therapeutics were excluded by skin testing, however further investigation determined that a povidone-containing formulation of paracetamol had been administered. Skin testing with povidone-containing paracetamol resulted in a positive reaction in the patient, but not in a volunteer control. Pharmaceutical excipients are added to medications to increase absorption, shelf-life and efficacy. Different brands of the same drug may contain different excipients. When testing for anaphylaxis with such compounds one must be sure the dilution is appropriate for both the parent compound and the excipient to ensure the accuracy of skin-prick and intradermal testing. This case demonstrates the potential for excipients to cause severe allergy and the importance of detailed history pertaining to previous allergic episodes as even the most unlikely of medications can potentially result in anaphylaxis due to excipients.

Methodological evaluation of human research on asthmagenicity and occupational cleaning: a case study of quaternary ammonium compounds ("quats")

In this paper, we review methodological approaches used in studies that evaluated the association between occupational exposure to quaternary ammonium compounds (quats) and occupational asthma. This association is of interest because quats are a common active ingredient of disinfectants and have been linked to work-related asthma in some circumstances. However, any evidence-based assessment of an exposure-outcome association needs to consider both strengths and limitations of the literature. We focus on publications cited by various US and international organizations. Eighteen investigations included in the review fall into two broad categories: case reports and challenge studies of individual patients and population studies that examined the association between quats and asthma occurrence in groups of subjects. We evaluated these studies guided by questions that address whether: exposure data on specific quat(s) and other agents that may cause asthma were included, new asthma cases were differentiated from asthma exacerbation, and information on respiratory sensitivity versus irritation was given. We also assessed consistency across studies. Studies of individual patients, particularly those that provided detailed information on challenge test results, document cases of asthma induced by exposure to quats. By contrast, studies of occupational groups with the highest potential for quats exposure (e.g., cleaners and farmers) do not consistently report increased incidence of asthma due specifically to quats. The unresolved methodological issues include: poor understanding of exposure pathways considering that quats are non-volatile, lack of quantitative data allowing for identification of an asthmagenicity threshold, insufficient information on whether quats are sensitizers or act via dose-dependent irritation or some other mechanism, and inability to quantify risk of new-onset asthma attributable to quats. Another important area of uncertainty is the lack of information on the specific quats being used. There is also a lack of data capable of distinguishing the effects of quats from those of other chemical and biological workplace exposures. The current state-of-the-science does not allow a proper assessment of the potential link between quats and occupational asthma.

Nasal Toxicity of Benzalkonium Chloride

Background

Benzalkonium chloride (BAC) is added to nasal preparations to prevent microbial contamination. Adverse effects of BAC on human nasal mucosa should be evaluated.

Methods

The ciliotoxicity of BAC was assessed in isolated human nasal epithelia from 15 donors. The effects of nasal BAC 0.05% (4 X 200 μL/day for 8 days) on nasal saccharin transport time, inflammatory cells and cytokine levels in nasal secretions, and nasal symptom scores were assessed in a randomized, double-blind crossover trial in 16 healthy volunteers.

Results

In vitro, BAC was ciliotoxic (p < 0.0001). In vivo, BAC did not alter saccharin transport time in healthy individuals (p > 0.8). No BAC-associated proinflammatory effects were observed. The staining index for myeloperoxidase was 4.8% in the placebo period and 6.3% (p = 0.42) in the BAC period. Also, nasal secretion levels of cytokines and the neuropeptide substance P revealed no BAC-associated differences. Concentrations for interleukin (IL)-6 in the placebo period were 41.5 pg/mL (0.9–91.7 pg/mL) and in the BAC period were 17.6 pg/mL (3.2–65.9 pg/mL; p = 0.46), and concentrations for substance P were 119 pg/mL (58–293 pg/mL) and 131 pg/mL (80–330 pg/mL; p = 0.31), respectively. Immediately after application, BAC caused nasal irritation (p = 0.001), a burning sensation (p = 0.0003), and hypersecretion (p = 0.006). Moreover, BAC caused a persistent sensation of nasal irritation (p < 0.01).

Conclusion

BAC in concentrations used in nasal preparations is ciliotoxic. In healthy individuals, the ciliotoxic effect of BAC is neutralized, probably by components of nasal secretions. No BAC-related proinflammatory effects have been observed. At higher doses than normally used therapeutically, BAC caused significant nasal irritation. (American Journal of Rhinology 18, 291–299, 2004)

Benzalkonium Chloride: A Bronchoconstricting Preservative in Continuous Albuterol Nebulizer Solutions

For convenience, many pediatric hospitals are preparing solutions for continuous nebulized albuterol using the 0.5% 20-ml multidose albuterol dropper bottle. This product contains benzalkonium chloride (BAC) that, by itself, produces bronchospasm that is dose dependent and cumulative. The bronchoconstrictive effects of BAC are greater in patients with more severe airway obstruction and increased airway responsiveness. Use of BAC-containing albuterol during severe acute asthma exacerbations may antagonize the bronchodilator response to albuterol, prolong treatment, and increase the risk of albuterol-related systemic adverse effects. Such a deleterious effect of BAC is difficult to detect because some patients improve slowly or may even worsen during treatment. We recommend that only preservative-free albuterol products be used.

Preservatives in eyedrops: the good, the bad and the ugly

There is a large body of evidence from experimental and clinical studies showing that the long-term use of topical drugs may induce ocular surface changes, causing ocular discomfort, tear film instability, conjunctival inflammation, subconjunctival fibrosis, epithelial apoptosis, corneal surface impairment, and the potential risk of failure for further glaucoma surgery. Subclinical inflammation has also been described in patients receiving antiglaucoma treatments for long periods of time. However, the mechanisms involved, i.e., allergic, toxic, or inflammatory, as well as the respective roles of the active compound and the preservative in inducing the toxic and/or proinflammatory effects of ophthalmic solutions, is still being debated. The most frequently used preservative, benzalkonium chloride (BAK), has consistently demonstrated its toxic effects in laboratory, experimental, and clinical studies. As a quaternary ammonium, this compound has been shown to cause tear film instability, loss of goblet cells, conjunctival squamous metaplasia and apoptosis, disruption of the corneal epithelium barrier, and damage to deeper ocular tissues. The mechanisms causing these effects have not been fully elucidated, although the involvement of immunoinflammatory reactions with the release of proinflammatory cytokines, apoptosis, oxidative stress, as well as direct interactions with the lipid components of the tear film and cell membranes have been well established. Preservative-induced adverse effects are therefore far from being restricted to only allergic reactions, and side effects are often very difficult to identify because they mostly occur in a delayed or poorly specific manner. Care should therefore be taken to avoid the long-term use of preservatives, otherwise a less toxic alternative to BAK should be developed, as this weakly allergenic but highly toxic compound exerts dose- and time-dependent effects. On the basis of all these experimental and clinical reports, it would be advisable to use benzalkonium-free solutions whenever possible, especially in patients with the greatest exposure to high doses or prolonged treatments, in those suffering from preexisting or concomitant ocular surface diseases, and those experiencing side effects related to the ocular surface. Indeed, mild symptoms should not be underestimated, neglected, or denied, because they may very well be the apparent manifestations of more severe, potentially threatening subclinical reactions that may later cause major concerns.

Delivery of antibiotics to the respiratory tract: an update

The use of inhaled medications for the treatment of pulmonary diseases has become an increasingly popular drug delivery route over the past few decades. This delivery route allows for a drug to be delivered directly to the site of the disease, with a lower dose than more conventional oral or intravenous delivery methods, with reduced systemic absorption and consequently reduced risk of adverse effects. For asthma this delivery route has become the 'golden standard' of therapy. It is not unexpected therefore, that there has been great interest in the prospect of using inhaled antibiotics for the treatment of both chronic and recurrent respiratory infections. Since the early 1980s, several investigations have demonstrated that antibiotics could be delivered safely by means of inhalation, using nebulisers as their delivery systems. Lately, antibiotics delivery via inhalation have seen a 'revival' in interest and most of these studies have focused on delivering antibiotics to the lungs by means of a dry powder format. This review focuses on recent advances in antibiotic inhalation therapy.

Benzalkonium chloride induced bronchoconstriction in patients with stable bronchial asthma

BACKGROUND

Although benzalkonium chloride (BAC)-induced bronchoconstriction occurs in patients with bronchial asthma, BAC-containing nebulizer solutions are still being used in daily practice in Korea. The aim of this study was to evaluate the effects of inhaled aqueous solutions containing BAC.

METHODS

Thirty subjects with bronchial asthma and 10 normal controls inhaled up to three 600 microg nebulized doses of BAC using a jet nebulizer. FEV1 (forced expiratory volume at one second) was measured 15 minutes after each dose. Inhalations were repeated every 20 minutes until FEV1 decreased by 15% or more (defined as BAC-induced bronchoconstriction) or the 3 doses were administered.

RESULTS

The percent fall in FEV1 in response to BAC inhalation was significantly higher in asthmatics than in normal subjects (p < 0.05). BAC administration in subjects with asthma reached a plateau (maximal effect). BAC-induced bronchoconstriction was found in 6 asthmatics (20%), with two responders after the 2nd inhalation and 4 after the 3rd inhalation. The percent fall in FEV1 in response to the 1st inhalation of BAC was significantly higher in asthmatics with higher bronchial hyperresponsiveness (BHR) than in those with lower BHR.

CONCLUSIONS

This study suggests that the available multi-dose nebulized solution is generally safe. However, significant bronchoconstriction can occur at a relatively low BAC dose in asthmatics with severe airway responsiveness.

Asthma exacerbations. 5: assessment and management of severe asthma in adults in hospital

It is difficult to understand why there is such a huge discrepancy between the management of severe asthma recommended by evidence-based guidelines and that observed in clinical practice. The recommendations are relatively straightforward and have been widely promoted both in guidelines and reviews. Specialist physicians need to be more proactive in their implementation of such guidelines through the use of locally derived protocols and assessment sheets, reinforced by audit. The common occurrence of severe asthma and its considerable burden to the community would support such an approach.

Over-the-counter topical antimicrobials: effective treatments?

There are many over-the-counter (OTC) bandage products available. In addition to their direct purchase by the public, many physicians provide OTC bandages to their patents after minor surgeries. The aim of this study was to evaluate in a well established porcine model the efficacy against Staphylococcus aureus of four OTC antimicrobial containing bandages as compared to two OTC ointments. Multiple partial thickness wounds were made on the backs of four pigs. The wounds were treated within 20 min after S. aureus inoculation. The wounds were cultured quantitatively at 24 and 48 h. Only one of the antibiotic bandages and one of the topical ointments were effective in reducing S. aureus proliferation in partial thickness wounds. The two treatments that were effective were the only treatments that contained neomycin. Although many OTC bandages and ointments contain antimicrobials, they may not be effective at reducing bacteria in wounds.

Inner-city availability of preservative-containing albuterol

Benzalkonium chloride (BAC) added to nebulized albuterol may induce bronchospasm. The objective of this study was to determine the availability of BAC-containing nebulized albuterol in the Bronx, New York pharmacies. A cross-sectional telephone survey of pharmacies was conducted. Overall, 158 (80%) pharmacies participated in the survey; 133 (84%) carried BAC-containing albuterol; 25 (16%) dispensed BAC-containing albuterol solution when presented with a prescription written for generic albuterol. Only 14 (9%) pharmacists had seen a prescription for nebulized albuterol where a physician specified "without BAC." Despite availability of BAC-free albuterol, pharmacies in the Bronx still carried and dispensed BAC-containing product.

Recent developments and future strategies for immunotherapy of insect venom allergy

PURPOSE OF REVIEW

Hymenoptera venom allergy may cause life-threatening, sometimes even fatal, allergic reactions and thus may be associated with a serious reduction in the quality of life. Venom immunotherapy is effective in the majority of patients with this allergy. Treatment failures do however occur and immunotherapy may cause frequent systemic allergic side effects, especially in honeybee venom-allergic patients. New strategies to improve safety and efficacy of this treatment are therefore of general interest.

RECENT FINDINGS

Among these new strategies are premedication with antihistamines: this definitely reduces side effects and based on recent in-vitro experiments and one clinical controlled study may even improve efficacy by modulating the T-cell response through interference with histamine receptors on these cells. Furthermore, during recent years the cDNA of most major allergens of bee and vespid venoms has been cloned and these allergens have been expressed in recombinant form. This allows for the preparation of patient-tailored extracts, with or without reduction of their allergenicity, for example by using unrefolded or point-mutated recombinant allergens. Yet another approach is the use of non IgE binding peptide fragments of the allergen with preserved T-cell epitopes for immunotherapy. Such preparations of bee venom phospholipase A2 have been used successfully in pilot studies. Finally, DNA vaccination with phospholipase A2 sequence plasmids has proved effective in one experimental study in sensitized mice.

SUMMARY

A number of new strategies for venom immunotherapy, mostly based on genetic engineering, have been described and we await their use in clinical medicine.

A comparison of nasal clearance after treatment of perennial allergic rhinitis with budesonide and mometasone

OBJECTIVE

Evidence in vitro suggests that benzalkonium chloride, a preservative in many intranasal preparations, interferes with ciliary function and thus could potentially interfere with mucociliary transport, the mechanism for clearing secretions from the nasal cavity.

STUDY DESIGN

We performed a parallel randomized study with 10 subjects in each arm comparing Rhinocort AQUA (an intranasal steroid [budesonide] spray without benzalkonium chloride) and Nasonex (an intranasal steroid [mometasone furoate] spray with benzalkonium chloride). Before and after 2 weeks of treatment, subjects completed a Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and underwent a measurement of nasal clearance of a radioactive colloidal spray into the nose.

RESULTS

The groups were matched at entry for nasal clearance, even though there was variability among subjects. The amount of change after 2 weeks of treatment (Delta before versus after treatment) showed a significant difference in nasal clearance favoring budesonide. After 2 weeks of treatment, both budesonide and mometasone demonstrated overall improvement in quality of life as assessed by the RQLQ. Both treatments were well tolerated.

CONCLUSION

Our study extends the observation in vitro that demonstrates the adverse effect of benzalkonium chloride on cilia to a measurement in vivo of clearance. The effects after 2 weeks might not reflect changes after longer periods of treatment.

SIGNIFICANCE

To determine the clinical significance of the small improvement in mucociliary transport will require large clinical trials.

Diagnosis of Hymenoptera venom sensitivity

PURPOSE OF REVIEW

The objective of this review is to highlight recent advances in the preparation, documentation and performance of reagents and methods used in the diagnosis of Hymenoptera-venom-induced immediate-type hypersensitivity.

RECENT FINDINGS

The following potent allergens have been reported: (1) a low-molecular-weight honey-bee allergen (Api m 6) has been described; (2) venom allergens in the North American species of bumble-bee (Bombus pennsylvanicus) have been more fully characterized, with the focus on phospholipase A2; (3) the vespid venom Ves v 5 allergen has been structurally mapped to identify immunoglobulin-E-binding epitopes; (4) the possible role of carbohydrate antigen epitopes as a cause of cross-reactivity among honey-bee and vespid venom proteins has been reported; and (5) the venom of Pachycondyla chinensis, an ant found commonly in the Far East, has been described. The most significant reports during this period have focused on the less-than-ideal performance of the intradermal venom skin-test reagents. The issue of the patient that is positive for venom allergy history but negative for an intradermal venom skin test is raised, and it is suggested that there is a need for caution and the use of serology as a supplementary diagnostic test.

SUMMARY

The important issue this year is the reminder that intradermal skin tests may be negative in venom-allergic patients, possibly because of changes in the potency of the extracts. The clinical history should drive the diagnosis of insect-sting allergy. When negative confirmatory venom skin-test or serology results are considered to be inconsistent with a positive history, they should be repeated.