Effect of inhaled preservatives on asthmatic subjects. II. Benzalkonium chloride

Inhaled mRNA therapy for treatment of cystic fibrosis: Interim results of a randomized, double-blind, placebo-controlled phase 1/2 clinical study

BACKGROUND

MRT5005, a codon-optimized CFTR mRNA, delivered by aerosol in lipid nanoparticles, was designed as a genotype-agnostic treatment for CF lung disease.

METHODS

This was a randomized, double-blind, placebo-controlled Phase 1/2 study performed in the US. Adults with 2 severe class I and/or II CFTR mutations and baseline ppFEV1 values between 50 and 90% were randomized 3:1 (MRT5005: placebo). Six dose levels of MRT5005 (4, 8, 12, 16, 20, and 24 mg) or placebo (0.9% Sodium Chloride) were administered by nebulization. The single ascending dose cohort was treated over a range from 8 to 24 mg; the multiple ascending dose cohort received five weekly doses (range 8-20 mg); and the daily dosing cohort received five daily doses (4 mg).

RESULTS

A total of 42 subjects were assigned to MRT5005 [31] or placebo [11]. A total of 14 febrile reactions were observed in 10 MRT5005-treated participants, which were mild [3] or moderate [11] in severity; two subjects discontinued related to these events. Additionally, two MRT5005-treated patients experienced hypersensitivity reactions, which were managed conservatively. The most common treatment emergent adverse events were cough and headache. No consistent effects on FEV1 were noted.

CONCLUSIONS

MRT5005 was generally safe and well tolerated through 28 days of follow-up after the last dose, though febrile and hypersensitivity reactions were noted. The majority of these reactions resolved within 1-2 days with supportive care allowing continued treatment with MRT5005 and careful monitoring. In this small first-in-human study, FEV1 remained stable after treatment, but no beneficial effects on FEV1 were observed.

Quaternary ammonium compounds in hypersensitivity reactions

Quaternary ammonium compounds (QAC) are commonly used disinfectants, antiseptics, preservatives, and detergents due to their antibacterial property and represent the first used biocides before phenolic or nitrogen products. Their common structure consists of one or more quaternary ammonium bound with four lateral substituents. Their amphiphilic structure allows them to intercalate into microorganism surfaces which induces an unstable and porous membrane that explains their antimicrobial activity towards bacteria, fungi, and viruses. QAC are thus found in many areas, such as household products, medicines, hygiene products, cosmetics, agriculture, or industrial products but are also used in medical practice as disinfectants and antiseptics and in health care facilities where they are used for cleaning floors and walls. QAC exposure has already been involved in occupational asthma in healthcare workers or professional cleaners by many authors. They also have been suggested to play a role in contact dermatitis (CD) and urticaria in workers using cosmetics such as hairdressers or healthcare workers, inciting reglementary agencies to make recommendations regarding those products. However, distinguishing the irritant or sensitizing properties of chemicals is complex and as a result, the sensitizing property of QAC is still controverted. Moreover, the precise mechanisms underlying the possible sensitization effect are still under investigation, and to date, only a few studies have documented an immunological mechanism. Besides, QAC have been suggested to be responsible for neuromuscular blocking agents (NMBA) sensitization by cross-reactivity. This hypothesis is supported by a higher prevalence of quaternary ammonium (QA)-specific IgE in the professionally exposed populations, such as hairdressers, cleaners, or healthcare workers, suggesting that the sensitization happens with structurally similar compounds present in the environment. This review summarizes the newest knowledge about QAC and their role in hypersensitivities. After describing the different QAC, their structure and use, the most relevant studies about the effects of QAC on the immune system will be reviewed and discussed.

Asthma-inducing potential of 28 substances in spray cleaning products-Assessed by quantitative structure activity relationship (QSAR) testing and literature review

Exposure to spray cleaning products constitutes a potential risk for asthma induction. We set out to review whether substances in such products are potential inducers of asthma. We identified 101 spray cleaning products for professional use. Twenty‐eight of their chemical substances were selected. We based the selection on (a) positive prediction for respiratory sensitisation in humans based on quantitative structure activity relationship (QSAR) in the Danish (Q)SAR Database, (b) positive QSAR prediction for severe skin irritation in rabbits and (c) knowledge on the substances' physico‐chemical characteristics and toxicity. Combining the findings in the literature and QSAR predictions, we could group substances into four classes: (1) some indication in humans for asthma induction: chloramine, benzalkonium chloride; (2) some indication in animals for asthma induction: ethylenediaminetetraacetic acid (EDTA), citric acid; (3) equivocal data: hypochlorite; (4) few or lacking data: nitriloacetic acid, monoethanolamine, 2‐(2‐aminoethoxy)ethanol, 2‐diethylaminoethanol, alkyldimethylamin oxide, 1‐aminopropan‐2‐ol, methylisothiazolinone, benzisothiazolinone and chlormethylisothiazolinone; three specific sulphonates and sulfamic acid, salicylic acid and its analogue sodium benzoate, propane‐1,2‐diol, glycerol, propylidynetrimethanol, lactic acid, disodium malate, morpholine, bronopol and benzyl alcohol. In conclusion, we identified an asthma induction potential for some of the substances. In addition, we identified major knowledge gaps for most substances. Thus, more data are needed to feed into a strategy of safe‐by‐design, where substances with potential for induction of asthma are avoided in future (spray) cleaning products. Moreover, we suggest that QSAR predictions can serve to prioritise substances that need further testing in various areas of toxicology.

We reviewed whether substances in spray cleaning products constitute a potential risk for asthma induction. For this, we identified 101 spray cleaning products for professional use and prioritised their ingredient substances by use of quantitative structure activity relationship (QSAR). We provide a review of 28 selected substances: we give conclusions on their asthma induction potential, as well as a discussion on the use of QSAR for prioritisation of substances, and the major knowledge gaps we encountered.

Continuous Albuterol With Benzalkonium in Children Hospitalized With Severe Asthma

BACKGROUND AND OBJECTIVES

The albuterol dropper bottle used to prepare solutions for continuous nebulization contains the preservative benzalkonium chloride (BAC). BAC, by itself, has been shown to cause bronchospasm. We hypothesized that BAC would decrease the therapeutic efficacy of albuterol in patients with acute asthma exacerbations.

METHODS

We performed a retrospective cohort study comparing the clinical outcomes of patients <18 years of age receiving continuous nebulized albuterol with and without BAC. For the primary end point (duration of continuous albuterol nebulization), we compared the 2 groups with Kaplan-Meier estimate of survival curves, conducted a log-rank test of difference, and adjusted for baseline characteristics using multivariable Cox regression. A P value <.05 was considered significant.

RESULTS

A total of 477 patients were included in the analysis (236 exposed to BAC and 241 controls). The duration of continuous nebulization was significantly longer in the BAC group than in the control group (median of 9 vs 6 hours; 15.7% required continuous nebulization compared to 5.8% of controls at 24 hours). The control group was 79% more likely to stop continuous nebulization at any particular point in time (hazard ratio 1.79; 95% confidence interval: 1.45 to 2.22; P < .001) and 43% more likely to stop additional respiratory support (hazard ratio 1.43; 95% confidence interval: 1.16 to 1.75; P < .001).

CONCLUSIONS

BAC is a functional albuterol antagonist associated with a longer duration of continuous albuterol nebulization treatment and additional respiratory support, suggesting that preservative-free albuterol formulations are safer for use in continuous nebulization.

Concentration- and Time-Dependent Effects of Benzalkonium Chloride in Human Lung Epithelial Cells: Necrosis, Apoptosis, or Epithelial Mesenchymal Transition

Benzalkonium chloride (BAC), an antimicrobial agent in inhalable medications and household sprays, has been reported to be toxic to pulmonary organs. Although cell membrane damage has been considered as the main cytotoxic mechanism of BAC, its concentration- and time-dependent cellular effects on lung epithelium have not been fully understood. In the present study, human lung epithelial (H358) cells were exposed to 0.2–40 μg/mL of BAC for 30 min or 21 days. Cell membranes were rapidly disrupted by 30 min exposure, but 24 h incubation of BAC (4–40 μg/mL) predominantly caused apoptosis rather than necrosis. BAC (2–4 μg/mL) induced mitochondrial depolarization, which may be associated with increased expression of pro-apoptotic proteins (caspase-3, PARP, Bax, p53, and p21), and decreased levels of the anti-apoptotic protein Bcl-2. The protein expression levels of IRE1α, BiP, CHOP, and p-JNK were also elevated by BAC (2–4 μg/mL) suggesting the possible involvement of endoplasmic reticulum stress in inducing apoptosis. Long-term (7–21 days) incubation with BAC (0.2–0.6 μg/mL) did not affect cell viability but led to epithelial-mesenchymal transition (EMT) as shown by the decrease of E-cadherin and the increase of N-cadherin, fibronectin, and vimentin, caused by the upregulation of EMT transcription factors, such as Snail, Slug, Twist1, Zeb1, and Zeb2. Therefore, we conclude that apoptosis could be an important mechanism of acute BAC cytotoxicity in lung epithelial cells, and chronic exposure to BAC even at sub-lethal doses can promote pulmonary EMT.

Determining the optimal time to assess the reversibility of airway obstruction

Context:

The optimal time to interpret bronchodilator reversibility remains controversial. This time may affect a positive diagnosis and manage asthma and chronic obstructive pulmonary disease (COPD).

Aims:

We sought to document the time when maximum respiratory function is reached after inhalation of salbutamol and to define the optimal time of bronchodilator response to assess the reversibility or non reversibility of airway obstruction.

Subjects and Methods:

This prospective analytical study was spread over 8 months and included 58 patients with asthma or COPD with airway obstruction. Spirometry was performed before and at 5, 10, 15, 20, and 30 min after salbutamol inhalation (200 mcg) administered through pressurized metered-dose inhalers and large volume spacer.

Results:

After salbutamol inhalation, the mean individual peak bronchodilation occurred at 20 min for the forced vital capacity and at 30 min for the forced expiratory volume in 1 s. The percentage of reversible patients in our sample was guideline dependent. It increased from 53% to 67.2% when using the American Thoracic Society/European Respiratory Society definition compared to using the Global Initiative for Chronic Obstructive Lung Disease. The maximum number of reversible patients was significantly different at 20 min compared to 5 and 10 min.

Conclusions:

Interpreting bronchodilator reversibility after 20 min was the ideal time to judge the reversibility or nonreversibility in obstructive ventilatory disorders in adults.

Sterility and Stability Testing of Preservative-free Albuterol

BACKGROUND

Continuous albuterol administration (CAA) is commonly used in hospitalized patients for treatment of asthma exacerbations. Due to higher dose requirements, CAA requires large volumes of albuterol obtained from multidose vials containing benzalkonium chloride (BAC). BAC is a common pharmaceutical preservative and potent bronchoconstrictor, which may antagonize the bronchodilation effects of albuterol. Some institutions are using preservative-free (PF) albuterol for their CAA. However, no published data currently exist to support the extended sterility or stability of this formulation.

OBJECTIVE

To evaluate the sterility and stability of PF-albuterol.

METHODS

Sterility testing was conducted for PF- and BAC-albuterol when stored at room temperature. Samples were incubated for 10 days in aerobic and anaerobic blood culture media to assess for bacterial growth. Stability of both albuterol formulations at high (0.67 mg/mL) and low (0.17 mg/mL) concentrations was determined at room temperature and under refrigeration. High performance liquid chromatography was used to evaluate samples up to 168 hours after preparation.

RESULTS

No bacterial growth was witnessed from either albuterol formulation at day 10 of observation. Both high and low concentrations of PF-albuterol and BAC-albuterol were stable at room temperature for up to 168 hours. There were no differences in stability between storage conditions for any formulation.

CONCLUSIONS

Under the current study conditions, there was no difference in sterility or stability for PF-albuterol when compared with BAC-albuterol. Thus, based on the findings of this study, PF-albuterol is sterile and stable up to 168 hours when stored at room temperature or under refrigerated conditions. The findings of this study do not confirm the therapeutic efficacy of PF-albuterol compared with BAC-albuterol for the treatment of asthma exacerbations. Further studies are warranted to determine the efficacy of PF-albuterol verses BAC-albuterol when used for CAA.

Safety and effectiveness of albuterol solutions with and without benzalkonium chloride when administered by continuous nebulization

PURPOSE

The results of a study to determine if rates of poor response differ in patients receiving continuous nebulized albuterol (CNA) therapy with or without the preservative benzalkonium chloride are presented.

METHODS

A retrospective analysis of the records of all patients who received CNA therapy at a large academic medical center from July 2015 to January 2016 was conducted. Data from patient evaluations performed before and after a change to benzalkonium chloride-containing albuterol were collected. The primary outcome was the rate of poor patient response, defined as a composite endpoint. Secondary outcomes included duration of therapy, dosing requirements, and duration of supplemental oxygen therapy.

RESULTS

There was no significant difference in rates of poor response between patients exposed (n = 80) and patients not exposed (n = 48) to benzalkonium chloride (16% and 17%, respectively; p = 0.95). The cohort not exposed to benzalkonium chloride had a median CNA duration of 7.0 hours, as compared with 10.5 hours for the cohort exposed to benzalkonium chloride, but this difference was not significant (p = 0.19). There were no significant differences between the benzalkonium chloride-exposed and nonexposed cohorts in the maximum dosing requirement (12.6 mg/hr versus 12.8 mg/hr, p = 0.89) or median duration of supplemental oxygen use (27.5 hours versus 16.5 hours, p = 0.77).

CONCLUSION

A study of hospitalized patients receiving CNA detected no significant difference in the frequency of poor response to therapy between groups receiving benzalkonium chloride-free versus benzalkonium chloride-containing albuterol products.

Effects of Some Preservative Agents on Rat and Guinea Pig Tracheal and Human Nasal Ciliary Beat Frequency

Many preservatives commonly included in nasal drops and sprays are known to impair mucociliary clearance. We studied the effects of four frequently used preservatives on ciliary beat frequency (CBF) in respiratory tissue. Sodium metabisulfite and chlorbutol did not change the CBF at concentrations up to 50 mg/L in rat tracheal mucosa. Chlorocresol 25 mg/L and 50 mg/mL reversibly decreased CBF (by 33% and 68%, respectively) in 60 minutes. Benzalkonium chloride impaired CBF irreversibly already at a relatively low concentration (12.5 mg/L). To further clarify these results, we studied the effects of the most ciliotoxic (benzalkonium chloride) and nonciliotoxic (chlorbutol) preservative on guinea pig tracheal epithelium and human nasal mucosa. Although chlorbutol had no effect on the CBF, a dose-dependent decrease on CBF was seen in guinea pig and human ciliated epithelium during their immersion in benzalkonium chloride. At a concentration of 50 mg/L it stopped the ciliary activity in 40 minutes in guinea pig trachea, and in human nasal mucosa, benzalkonium chloride concentrations of 25 and 50 mg/L, decreased the CBF irreversibly (by 28% and 60%, respectively) in 60 minutes. These results suggest that chlorbutol is a safe and well tolerated preservative. Banzalkonium chloride is ciliostatic in vitro to rat, guinea pig, and human respiratory mucosa. Therefore, prolonged clinical use of benzalkonium chloride may impair mucociliary clearance, a major defense respiratory mechanism.

Pulmonary Toxicity of Benzalkonium Chloride

The available toxicity data of benzalkonium chloride (BKC) clearly shows that it is toxic; however, the weight of evidence favors the view that at doses encountered in nasally and orally inhaled pharmaceutical preparations it is well tolerated. The adverse toxicological data predominantly come from in vitro and animal studies in which doses and exposure periods employed were excessive in relation to the clinical doses and their posology and, therefore, not directly applicable to the clinic. The conflict between the in vitro and animal data and the clinical experience can be reconciled by understanding some of the physicochemical properties of BKC, the nasal and respiratory tract microenvironments, the doses used, and the posology.

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.

Paradoxical bronchospasm from benzalkonium chloride (BAC) preservative in albuterol nebulizer solution in a patient with acute severe asthma. A case report and literature review of airway effects of BAC

Nebulized bronchodilator solutions are available in the United States as both nonsterile and sterile-filled products. Sulfites, benzalkonium chloride (BAC), or chlorobutanol are added to nonsterile products to prevent bacterial growth. Bronchoconstriction from inhaled BAC is cumulative, prolonged, and correlates directly with basal airway responsiveness. The multi-dose dropper bottle of albuterol sulfate solution contains 50 μg BAC per/2.5 mg of albuterol, which may be below or at the lower limit of the threshold dose for bronchoconstriction. However, with repeated albuterol nebulization, the effect can be additive and cumulative, often exceeding the bronchoconstriction threshold. We report a case of a 17 years old patient, who received 32 mg of BAC via nebulization over a period of 3.5 days that probably caused persistent bronchospasm evidenced by failure to improve clinically and to increase peak expiratory flow rate (PEFR) from 125 L/min (27% of predicted value) to 300 L/min (68% of predicted value) within 2 hours of withdrawing BAC. The patient's respiratory status and PEFR improved dramatically once the nebulization solution was switched to BAC free lev-albuterol solution. The pediatric providers, particularly the emergency department physicians, intensivists and pulmonologists need to be aware of this rare albeit possible toxicity to the respiratory system caused by BAC used as a preservative in albuterol nebulizer solution.

Long-Term Efficacy and Safety of Ipratropium Bromide plus Fenoterol via Respimat((R)) Soft Misttrade mark Inhaler (SMI) versus a Pressurised Metered-Dose Inhaler in Asthma

OBJECTIVE

Respimat((R)) Soft Misttrade mark Inhaler (SMI) is a novel, propellant-free device that significantly increases lung deposition compared with pressurised metered-dose inhalers (pMDIs). The aim of this study was to compare the efficacy and safety of ipratropium bromide/fenoterol hydrobromide (IB/FEN; Berodual((R))) delivered via Respimat((R)) SMI and via a chlorofluorocarbon (CFC)-driven pMDI (CFC-MDI) in patients with asthma.

DESIGN

Multicentre, randomised, double-blind, placebo-controlled, parallel- group study.

PATIENTS

631 patients (18-65 years old) with stable asthma.

INTERVENTIONS

After a 2-week run-in period (IB/FEN 20mug/50mug via CFC-MDI, two actuations four times a day), patients were randomised to 12 weeks' treatment with one of five treatments: IB/FEN 10mug/25mug, 20mug/50mug or placebo via Respimat((R)) SMI (one actuation four times a day), or IB/FEN 20mug/50mug or placebo via CFC-MDI (two actuations four times a day). The main efficacy measure was lung function (assessed on days 1, 29, 57 and 85); safety was assessed by monitoring adverse events.

RESULTS

Bronchodilator responses to IB/FEN were much greater than those to placebo (mean peak increases in forced expiratory volume in 1 second [FEV(1)] on day 85: 0.498-0.521L, active treatment; 0.215 and 0.240L, placebo). According to the primary endpoint, i.e. the average change in FEV(1) from test-day baseline over the 6 hours after dosing on day 85, neither IB/FEN dosage via Respimat((R)) SMI was inferior to IB/FEN via pMDI (p < 0.001). Non-inferiority of the two Respimat((R)) SMI dosages was supported by analyses of other lung function measures, e.g. average change in FEV(1) from test-day baseline over the 6 hours after dosing on the other 3 test days, and peak FEV(1) on all test days. Overall, the safety profile of IB/FEN via Respimat((R)) SMI was comparable to that via CFC-MDI.

CONCLUSION

IB/FEN from Respimat((R)) SMI is as effective and safe as from CFC-MDI and enables a 2- to 4-fold daily dose reduction of IB/FEN.

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.

Low incidence of paradoxical bronchoconstriction in asthma and COPD patients during chronic use of Respimat soft mist inhaler

Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler that offers improved lung deposition compared with chlorofluorocarbon metered dose inhalers (CFC-MDIs). Bronchodilators administered via Respimat SMI are preserved and stabilised with low concentrations of benzalkonium chloride and ethylene diamine tetra-acetic acid, both of which have been reported to cause dose-related paradoxical bronchoconstriction. The aim of this analysis was to compare the incidence of paradoxical bronchoconstriction after chronic use of bronchodilators via Respimat SMI and CFC-MDI. Data from three clinical trials, in which patients with asthma or chronic obstructive pulmonary disease (COPD) received ipratropium bromide alone or in combination with fenoterol hydrobromide, or placebo via Respimat SMI or CFC-MDI for 12 weeks, were included in the analysis. In order to evaluate the risk of paradoxical bronchoconstriction, we identified four respiratory events that might have occurred within 30 min of inhalation on four test days; these were: 'bronchospasm', 'other respiratory adverse events', 'rescue medication use' and 'asymptomatic drop in FEV(1) 15% from baseline'. In total, 631 asthma and 1538 COPD patients participated in the three studies. No occurrences of bronchospasm were reported with Respimat SMI on any test day. Overall, the incidence of respiratory events possibly indicative of paradoxical bronchoconstriction was low and similar for both devices. There was no increase in the incidence of events during 12 weeks' treatment. Delivery of bronchodilators by Respimat SMI is safe with regard to paradoxical bronchoconstriction during chronic use in patients with asthma or COPD.

Inhaled ethanolic and aqueous solutions via Respimat Soft Mist Inhaler are well-tolerated in asthma patients

BACKGROUND

Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler offering improved lung deposition compared with other devices. Bronchodilators administered via Respimat SMI are preserved and stabilized with benzalkonium chloride (BAC) and ethylene diamine tetra-acetic acid (EDTA); both have been reported to cause paradoxical bronchoconstriction if a threshold dose is exceeded.

OBJECTIVE

The aim of this randomized, double-blind, three-period, crossover study was to establish that the safety of inhaled ethanolic and aqueous placebo solutions (containing BAC and EDTA) is equivalent to that of inhaled normal saline solution when administered to asthma patients via Respimat SMI.

METHODS

Thirty-seven asthma patients with airway hyper-reactivity were randomized to receive four actuations of each of the following three treatments via Respimat SMI, one on each of 3 study days: ethanolic placebo (12 microl 96% ethanol + 0.13 mug EDTA/actuation), aqueous placebo (12 microl water + 5.5 microg EDTA + 1.1 mug BAC/actuation), and normal saline (12 microl 0.9% sodium chloride/actuation). Pulmonary function tests were performed at baseline and at 5, 15, 30, 60, 120 and 180 min after inhalation; the primary endpoint was the lowest FEV(1) recorded between 0 and 30 min.

RESULTS

The mean lowest FEV(1) recorded between 0 and 30 min after inhalation minus the study day baseline was -0.090 litres for ethanolic placebo, -0.121 litres for aqueous placebo and -0.094 litres for normal saline (SEM 0.034 litres for all). The mean treatment differences were: ethanolic placebo versus normal saline 0.004 litres (90% CI -0.075-0.083 litres, p = 0.002), and aqueous placebo versus normal saline -0.028 litres (90% CI -0.107-0.052 litres, p = 0.006). Since both 90% CIs fell within the pre-determined equivalence region of +/-0.15 litres, both treatments were considered equivalent to normal saline.

CONCLUSION

Ethanolic and aqueous solutions administered via Respimat SMI are safe with regard to paradoxical bronchoconstriction in asthma patients with airway hyper-reactivity.

Identification of benzalkonium chloride in commercial grapefruit seed extracts

Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography (HPLC), electrospray ionization mass spectrometry (ESI/MS), tandem mass spectrometry (ESI/MS/MS), and elemental analysis (by proton-induced X-ray emission analysis). Three major constituents were observed by HPLC and were identified as benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. This mixture of homologues is commonly known as benzalkonium chloride, a widely used synthetic antimicrobial ingredient used in cleaning and disinfection agents.

Preventive effect of lacrimal occlusion on topical timolol-induced bronchoconstriction in asthmatics

AIM

To evaluate the potential preventive role of lacrimal occlusion on the topical timolol-induced bronchoconstriction in asthmatics.

METHODS

This was a prospective and single-masked study. Fourteen volunteer subjects with asthma were included. Collagen plugs were inserted into both canaliculi on one side to inhibit lacrimal drainage. The effect of lacrimal occlusion on lung function tests was measured before and 60 min after the instillation of a timolol drop in unplugged and plugged eyes. The spirometric measurements include forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, and mid expiratory flow-rate (FEF25-75).

RESULTS

The timolol (0.5%) drop administration into the eye caused a significant decrease in pulmonary functions in patients with asthma in whom the lacrimal punctae had not been occluded by collagen plug. P values were 0.008 for FVC and 0.001 for FEV1 and FEF25-75. The occlusion of the lacrimal duct by intracanalicular plugs significantly reduced this decrease in pulmonary function. P values were 0.6 for FVC, 0.8 for FEV1, and 0.5 for FEF25-75. The lacrimal occlusion did not affect heart rate and blood pressures. Three subjects complained of epiphora.

CONCLUSIONS

Lacrimal occlusion with intracanalicular collagen plugs may almost completely prevent the bronchoconstriction caused by topical timolol in asthmatics by inhibiting or decreasing systemic absorption of the medication.

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.

Efficacy and safety of ipratropium bromide plus fenoterol inhaled via Respimat Soft Mist Inhaler vs. a conventional metered dose inhaler plus spacer in children with asthma

The objective of this study was to compare the efficacy and safety of ipratropium bromide/fenoterol hydrobromide (IB/FEN; Berodual) delivered from the novel propellant-free Respimat Soft Mist Inhaler (SMI) with that from a chlorofluorocarbon (CFC) metered-dose inhaler (MDI) plus spacer in children with asthma. The study followed a multicenter, randomized, double-blind (within Respimat SMI), parallel-group design. During the 2-week run-in period, patients received two actuations of CFC-MDI tid (IB 20 microg/FEN 50 microg per actuation) via a spacer (Aerochamber) (MDI 40/100). Patients (n=535) were then randomized to: Respimat SMI containing IB 10 microg/FEN 25 microg (Respimat SMI 10/25), IB 20 microg/FEN 50 microg (Respimat SMI 20/50), one actuation tid or CFC-MDI containing IB 20 microg/FEN 50 microg per actuation (in total 1B 40 microg/FEN 100 microg), or two actuations tid via Aerochamber (MDI 40/100), for 4 weeks. The primary endpoint was the change in forced expiratory volume in 1 second (FEV1) during the first 60 min after dosing (area under the curve from 0-1 h [AUC(0-1 h)]) on day 29. Analysis of the primary endpoint demonstrated that the efficacy of Respimat SMI 10/25 and 20/50 was equivalent to or greater than that of MDI 40/100. Similar results indicating that Respimat SMI 10/25 and 20/50 were not inferior to MDI 40/100 were also found on days 1 and 15. Analyses of other secondary endpoints supported these results. The safety profile of Respimat SMI was comparable to that of the CFC-MDI plus spacer. In conclusion, IB/FEN delivered via Respimat SMI is at least as effective as, and is as safe as, when delivered via CFC-MDI plus Aerochamber in children with asthma. Use of Respimat SMI thus enables a 2-4-fold reduction in the nominal dose of IB/FEN, and obviates the need for a spacer.

Levalbuterol: pharmacologic properties and use in the treatment of pediatric and adult asthma

LEARNING OBJECTIVES

To review the rationale supporting the use of levalbuterol [(R)-albuterol] for the treatment of pediatric and adult asthma.

DATA SOURCES

Peer-reviewed articles, selected abstracts from studies presented at recent professional meetings, and the Xopenex [levalbuterol, (R)-albuterol; Sepracor, Marlborough, MA] Summary Basis of Approval and package insert.

STUDY SELECTION

Institutional review board-approved clinical study protocols.

RESULTS

Levalbuterol is a single isomer beta2-agonist that differs from racemic albuterol by elimination of (S)-albuterol. Levalbuterol is an effective bronchodilator whose primary mechanism of action is unimpeded by (S)-albuterol. Thus, when compared with racemic albuterol, clinically comparable bronchodilation can be achieved with doses that substantially lessen beta-mediated side effects. In chronic or acute treatment of asthma, this favorable therapeutic profile cannot apparently be duplicated by increasing or decreasing the dose of racemic albuterol or by the addition of anticholinergic agents such as ipratropium bromide.

CONCLUSIONS

Levalbuterol seems to provide efficacy and safety advantages in pediatric and adult patients suffering from asthma. Its use may afford a cost benefit as well. More clinical studies are required to extend these observations for use in the treatment of other pulmonary diseases in both adults and children and to determine levalbuterol's impact on long-term therapy of respiratory diseases.

Preliminary data from phase II studies with Respimat, a propellant-free soft mist inhaler

Inhalation is regarded as the most effective treatment for respiratory disorders. Boehringer Ingelheim (Ingelheim am Rhein, Germany) has developed Respimat, a soft mist inhaler that delivers a metered dose of drug solution as an aerosol with a high "fine particle fraction" approximately five times slower than aerosols from chlorofluorocarbon-driven metered dose inhalers (CFC-MDIs). These characteristics have led to improved drug deposition in the lungs. In scintigraphic studies using fenoterol and flunisolide, mean drug delivery to the lungs was 31.1 to 44.6% of the dose delivered using Respimat compared with less than 20% using a CFC-MDI. Clinical studies in asthmatic patients using inhaled fenoterol alone (Berotec; Boehringer Ingelheim) or combined with ipratropium bromide (Berodual; Boehringer Ingelheim) confirmed the hypothesis that lower doses administered using Respimat should produce bronchodilator effects similar to those obtained with standard doses administered via a CFC-MDI. For Berotec, 12.5 or 25 micrograms administered by Respimat was therapeutically equivalent to either 100 or 200 micrograms administered by a CFC-MDI. For Berodual, bronchodilatory effects of 25/10- or 50/20-microgram doses using Respimat tended to be close or slightly superior to those of 100/40 micrograms using a CFC-MDI. Safety profiles did not differ between Respimat and CFC-MDI administration in either trial. Patients with airway hyperreactivity who inhaled placebo or drug solutions containing different preservatives and stabilizers had low incidences of paradoxical bronchoconstriction or asymptomatic decreases in lung function, which were similar with Respimat and a CFC-MDI. Furthermore, facial deposition data suggest a low risk of untoward effects even in potential misuse situations. Thus, Respimat promises to be a valuable alternative to conventional CFC-MDIs, with the additional benefit of improved drug targeting to the lungs.

"Inactive" ingredients in pharmaceutical products: update (subject review). American Academy of Pediatrics Committee on Drugs

Because of an increasing number of reports of adverse reactions associated with pharmaceutical excipients, in 1985 the Committee on Drugs issued a position statement recommending that the Food and Drug Administration mandate labeling of over-the-counter and prescription formulations to include a qualitative list of inactive ingredients. However, labeling of inactive ingredients remains voluntary. Adverse reactions continue to be reported, although some are no longer considered clinically significant, and other new reactions have emerged. The original statement, therefore, has been updated and its information expanded.

Occupational asthma due to indirect exposure to lauryl dimethyl benzyl ammonium chloride used in a floor cleaner

The case is described of a 44 year old pharmacist who developed severe occupational asthma threatening his continued employment, confirmed by serial measurement of peak expiratory flow at home and work. The cause was found to be the cleaning agent used in his office when it was unoccupied. Bronchial challenge testing identified the specific agent to which he was sensitised as lauryl dimethyl benzyl ammonium chloride, a constituent of the floor cleaner. Substitution of this floor cleaner by a simple detergent cleaner led to a substantial improvement in his asthma, confirmed by repeated serial peak flow measurements.

Therapeutic controversies in the treatment of asthma

OBJECTIVE

To introduce readers to the current controversial topics in the area of asthma therapy. Background is provided such that clinicians are aware of these issues and can make rational decisions.

DATA SOURCES

Pertinent articles were individually identified and reviewed from each journal.

STUDY SELECTION

Relevant studies, determined by topic and other specific criteria, e.g., testing methodology, were included.

DATA SYNTHESIS

Further investigation is required in the areas discussed. Systemic effects, specifically growth suppression (in children), adrenal suppression, and osteoporosis, have been demonstrated with high-dose inhaled glucocorticoids; however, the clinical relevance of such intravenous glucocorticoid formulations via nebulizer have not been demonstrated. Likewise, data on the equivalence of the inhaled glucocorticoids, with regard to efficacy and potential systemic effects, and the differences between metered-dose inhalers and dry powder inhalers, with regard to aerosol characteristics and drug delivery, are unclear. Theophylline, when used with inhaled beta-adrenergic agonists and systemic glucocorticoids for the treatment of acute asthma, as not been shown to provide clear benefit and may result in increased adverse effects. The use of regular (vs. "as needed" or prn) inhaled beta-adrenergic agonists, although shown in two studies to be detrimental to the control of asthma and result in an increased risk of death or near death caused by asthma, has not been conclusively demonstrated to be harmful.

CONCLUSIONS

Monitoring for adverse effects and the use of techniques to minimize systemic absorption (spacers and mouth rinsing) are recommended when high-dose inhaled glucocorticoid therapy is used. Intranasal and intravenous glucocorticoid products are not recommended for administration via nebulizer because of safety concerns. Until further data are available, inhaled glucocorticoids are thought to be equivalent on a microgram-per-microgram basis rather than an actuation-per-actuation basis. Theophylline is no longer recommended for treatment of acute exacerbations in nonhospitalized patients not already receiving the medication, and the link between deterioration of asthma control (and the risk for death) and regular inhaled beta-adrenergic agonists appears weak.

Possible association of benzalkonium chloride in nebulizer solutions with respiratory arrest

OBJECTIVE

To report a case of possible association of benzalkonium chloride in nebulizer solutions with respiratory arrest and to review the involvement of various preservative agents in paradoxical bronchoconstrictive reactions.

DATA SOURCES

Reference articles, case reports, and editorials are identified in the text.

DATA SYNTHESIS

Many pharmacologic agents are available for nebulization. In addition to the active drug, these nebulizer solutions may contain preservatives. We describe a case of respiratory arrest in a 64-year-old man following nebulization therapy with albuterol and ipratropium solutions. These solutions contain benzalkonium chloride as a preservative. We are aware of only one report describing two deaths associated with such a severe reaction attributable to nebulization therapy. However, many reports of milder paradoxical bronchoconstriction are available in the medical literature.

CONCLUSIONS

Clinicians should be aware of the possibility of paradoxical bronchoconstrictive reactions when patients are treated with nebulized bronchodilators.

Hypoxaemia after nebulised salbutamol in wheezy infants: the importance of aerosol acidity

The effect of nebulised iso-osmolar, preservative free, but acidic salbutamol solution was studied in 34 acutely wheezing infants aged 1-17 months. Transcutaneous oxygen pressure (TcPO2) and oxygen saturation (SO2) fell significantly during the first five minutes after nebulisation with further deterioration at 15-20 minutes. Ten of these infants were followed up for another two hours and showed slight improvement. Even after the second hour TcPO2 had not reached baseline values. Three months later the response to salbutamol and a placebo of equal acidity (pH 3.9) was studied in 11 infants from the same group, now free of symptoms. Lung function tests were included and showed no significant changes in specific conductance and volume corrected maximum expiratory flows (Vmax at functional residual capacity/thoracic gas volume). However, hypoxaemia occurred after the acidic placebo with a significant drop of TcPO2 (mean 0.9 kPa); SO2 decreased similarly but this did not reach significance. After salbutamol there was a further significant deterioration of mean TcPO2 (1.4 kPa) and of SO2. These results show that beside a possible pharmacological effect of salbutamol the acidity of the aerosol also induces hypoxaemia in infants.

Asthma and chronic obstructive lung disease: a pharmacologic approach

Changing concepts are emerging that should improve our ability to adequately treat asthma. This volume of Disease-a-Month reviews the triggers and the role of inflammation in asthma, and outlines the treatment of acute asthma as well as the chronic management of reversible obstructive airways disease. There is general agreement that sympathomimetics are the treatment of choice for acute severe asthma. The role of theophylline for acute symptoms has been downplayed, and the role of corticosteroids continues to be debated. However, most authorities agree that patients with severe asthma will benefit from the addition of corticosteroids to the program. For the chronic management of asthma, appreciation that inflammation is a perpetuating feature suggests that treatment should generally be directed toward the inflammation. Corticosteroid aerosols have taken on greater prominence and have been advocated as the first line of approach. New concepts regarding the role of allergy in the perpetuation of asthma and the role of immunotherapy in its amelioration also have emerged. Medications not previously thought to be beneficial are being actively investigated. They include gold, methotrexate, and even intravenous gamma globulin.