Severe asthma: follow-up after one year from the Italian Registry on Severe Asthma (IRSA)

Summary: Background. Asthma affects millions of people worldwide, with a subgroup suffering from severe asthma (SA). Biologics have revolutionized SA treatment, but challenges remain in managing different patient traits. This study analyzed data from the Italian Registry on Severe Asthma (IRSA) to investigate changes in SA characteristics and effectiveness of treatments after one year of follow-up, and to identify factors associated with response to treatments in a real-world setting. Methods. Data on SA patients with one year of follow-up were extracted from IRSA. Asthma control, exacerbations, lung function, and treatments, were assessed at follow-up and analyzed against baseline characteristics. Results. After one year of follow-up, notable improvements were observed in all the outcomes of SA of the included patients (n = 570). The effectiveness of biologic therapies was particularly evident, as they contributed significantly to these positive outcomes. Additionally, certain factors were found to be associated with improvement, namely T2 phenotype, baseline eosinophil count (BEC), and area of residence. On the other hand, comorbidities (obesity, gastro-esophageal reflux disease) and poor lung function were risk factors. Notably, poor-responders to biologics exhibited lower level of education, BEC, and exacerbations, and higher frequency of atopy and ACT score ≥ 20. Conclusions. The findings demonstrate the effectiveness of biologics in asthma management, when implemented as part of a planned follow-up strategy aimed at optimizing and fine-tuning the therapy. Moreover, the study highlights the importance of considering key traits such as the T2 phenotype, BEC, education, and comorbidities when tailoring SA treatment. Overall, this study contributes to enhancing our understanding of SA management and guiding the development of personalized treatment approaches for patients with SA.

From triggers to asthma: a narrative review on epithelium dysfunction.

Summary: It is currently recognized that the airway epithelium plays a pivotal role in orchestrating inflammatory, immune, and regenerative responses to allergens, viruses and environmental pollutants that contribute to asthma pathogenesis. The impact of pollen on respiratory epithelium is multifaceted and goes beyond the direct barrier damage driven by the best-known Type-2 response. After pollen-driven activation, airway epithelial cells play an active role in triggering several pathways. In particular, the release of epithelial cytokines (or alarmins) activates both innate and adaptive immunity, with downstream effects implicated to the pathogenesis of asthma. Pollutants also have a pleiotropic effect on respiratory epithelium. Diesel exhaust particles can directly damage the respiratory epithelium with consequent barrier dysfunction, increased permeability, and local inflammation, but they can also activate Th2 responses. Innate immune responses also are triggered by pollutants through release of epithelial cytokines and redox-sensitive pathways that generate mechanical and immunologic changes in the respiratory epithelium. In addition to the typical Type-1 immune response, respiratory virus infections stimulate type-2 innate lymphoid cells in the airway epithelium to release epithelial cytokines. Finally, the action of epithelial triggers on airway smooth muscle is the central element in the induction of remodeling and hyperreactivity of the airways in asthma. This article reviews the pathophysiology and functions of the airway epithelium and the role of epithelial damage by different triggers in the development, persistence, and exacerbations of asthma.

Severe asthma management in the era of biologics: insights of the Italian Registry on Severe Asthma (IRSA).

Summary: Background. The Italian Registry on Severe Asthma (IRSA) is the most recent and largestregistry in Italy. Objective. To improve the knowledge on the clinical and biological features of severe asthma (SA), and to monitor its treatments. Methods. To analyze clinical,functional, inflammatory, and treatment characteristics of severe asthmatics from the IRSA registry. Results. 851 subjects were enrolled. 31.8% and 64.5% of patients were submitted to oral corticosteroids (OCS), and monoclonal antibodies (MABs), respectively. At least tw ocomorbidities affected 77.4% patients. Asthma was uncontrolled in 62.2% patients. Uncontrolled patients had a higher frequency of exacerbations, and hospitalization, showing a highere osinophilic phenotype, a greater use of OCS, and being treated with MAB less frequently. However, uncontrolled patients treated with MAB had a lower use of OCS and a lower rateof hospitalization. Comparing SA patients with atopy and without atopy, the latter showeda greater use of OCS, and more frequent nasal polyposis and osteoporosis. Among SA patients with atopy treated with MAB, 36% were on a treatment targeting the IL-5 pathway. Conclusions and clinical relevance. This study shows the features of the greatest Italian registryof SA patients, revealing at the time of enrollment a poor disease control, and the use of OCSand MABs in about one third and two thirds of patients, respectively. SA is a complex diseasethat requires a more precise phenotyping and a greater disease control.

Severe asthma in adolescents and adults: a national, multicenter registry in real life.

Summary: The number of patients with uncontrolled asthma is growing especially in young people. Although current therapies improve the disease management, the heterogeneity of clinical outcomes results in patients whose asthma is refractory to standard therapies. To understand not responsive phenotypes, we instituted a web-registry aimed to collect real life data of adolescent and adult patients. One-hundred and five Italian medical Centers are part of the network. Participants above 14 years and affected by severe asthma will be included in the study. Demographic and clinical data will be collected for 5 years on a dedicated electronic database. For the first time in Italy, our study will provide information on epidemiological, clinical and therapeutic aspects related to the natural course of the disease, filling the gap between adolescents and adults.

Can healthcare utilization data reliably capture cases of chronic respiratory diseases? a cross-sectional investigation in Italy.

BACKGROUND: Healthcare utilization data are increasingly used for chronic disease surveillance. Nevertheless, no standard criteria for estimating prevalence of high-impact diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are available. In this study an algorithm for recognizing COPD/asthma cases from HCU data is developed and implemented in the HCU databases of the Italian Lombardy Region (about 10 million residents). The impact of diagnostic misclassification for reliably estimating prevalence was also assessed. METHODS: Disease-specificdrug codes, hospital discharges together with co-payment exemptions when available, and a combination of them according with patient's age, were used to create the proposed algorithm. Identified cases were considered for prevalence estimation. An external validation study was also performed in order to evaluate systematic uncertainty of prevalence estimates. RESULTS: Raw prevalence of COPD and asthma in 2010 was 3.6 and 3.3% respectively. According to external validation, sensitivity values were 53% for COPD and 39% for asthma. Adjusted prevalence estimates were respectively 6.8 and 8.5% for COPD (among person aged 40 years or older) and asthma (among person aged 40 years or younger). CONCLUSIONS: COPD and asthma prevalence may be estimated from HCU data, albeit with high systematic uncertainty. Validation is recommended in this setting.

Near fatal asthma: treatment and prevention.

Near-fatal asthma (NFA) is described as acute asthma associated with a respiratory arrest or arterial carbon dioxide tension greater than 50 mmHg, with or without altered consciousness, requiring mechanical ventilation. Risk factors for near fatal asthma have not been fully elucidated. In 80-85% of all fatal events, a phenotype, characterized by eosinophilic inflammation associated with gradual deterioration occurring in patients with severe and poorly controlled asthma, has been identified. Regarding to the management, acute severe asthma remains a significant clinical problem, which needs to be identified to facilitate early and appropriate therapeutic interventions. The assessment relies on clinical signs, but additional information might be obtained from chest radiography or blood gas analysis. No investigation should delay the initiation of appropriate therapy. The goals of therapy are the maintenance of oxygenation, relief of airflow obstruction, reduction of airways edema and mucus plugging (with Increased use of medications such as beta-agonists via metered dose inhalers and nebulizers, oral and/or intravenous (other than by inhalation) corticosteroids and oral or intravenous theophylline) whereas supporting ventilation as clinically indicated. Of course, the emergency physician needs to consider the wide range of potential complications, as attention to these problems when managing severe acute asthma might significantly improve outcome. An understanding of the available agents and potential pitfalls in the management of NFA is mandatory for the emergency physician.

Prevalence of airflow obstruction according GOLD, ATS and ERS criteria in symptomatic ever-smokers referring to a pulmonary rehabilitation department.

AIM: To evaluate in a Pulmonary Rehabilitation (PR) setting the prevalence of airflow obstruction (AO) in either current or former smokers > or = 45 years old both with dyspnoea and with chronic productive cough, using European Respiratory society (ERS) statement (FEV1/SVC < 88 and < 89% predicted in men and women, respectively), American Thoracic Society (ATS) statement (FEV1/FVC < 75%), and Global Initiative for Chronic Obstructive Lung Disease (GOLD) statement (FEV1/FVC < 70%). METHODS: Lung function tests were performed in each patient who was referred to our PR department due to respiratory diagnosis or symptoms. For analysis, in patients showing AO we used post-bronchodilator lung function values. RESULTS: In 184 ever-smoker patients with symptoms of chronic obstructive pulmonary disease (COPD), the prevalence rates of AO were as follows: ERS = 89.7%, ATS = 76.6%, and GOLD = 63.6%. Patients with AO according ERS criteria showing moderate to severe (M/S) obstruction (i.e., FEV1 < 70% predicted) were 119. Patients with ERS M/S AO but without AO using either ATS or GOLD criteria were 8.4% and 19.3%, respectively. CONCLUSIONS: Prevalence of AO is highly dependent on which guidelines it is based. ATS and particularly GOLD statement can cause a large under-diagnosis even of moderate to severe COPD. Diagnosis of COPD may be overlooked if SVC is not performed.

In vitro comparison of nebulised budesonide (Pulmicort Respules) and beclomethasone dipropionate (Clenil per Aerosol).

This study compared the in vitro performance of two inhaled corticosteroid products for nebulisation, Pulmicort Respules(budesonide 0.5 mg/mL) and Clenil) per Aerosol (beclomethasone dipropionate (BDP) 0.4 mg/mL). Each product was used in combination with three different nebulisers (2 mL/test, 5 min run time) and the dose to the lungs was determined according to standard methods. The shape of the suspended particles in each product was studied using scanning electron microscopy (SEM). Overall, a higher fine particle dose was achieved with Pulmicort Respules versus Clenil per Aerosol, with estimated dose to the lungs of 8-14 and 3-6% of nominal dose, respectively. SEM showed that budesonide particles were small, typically approximately 2-3 microm in diameter, whereas those of BDP were needle-shaped and up to approximately 10 microm long. The more favourable particle shape and size of suspended budesonide may explain the higher fine particle dose with Pulmicort Respules versus Clenil per Aerosol.

Different effects of inhaled aspirinlike drugs on allergen-induced early and late asthmatic responses.

Little is known about the anti-asthmatic effects of powerful anti-inflammatory agents such as aspirin-like drugs. We compared the effects of two aspirin-like drugs with different pharmacologic activities, sodium salicylate (SSA) and indomethacin, with the effect of lysine acetylsalicylate (LASA), inhaled 30 min before challenge, on the early and the late asthmatic response induced by a single dose of allergen causing a 25% decrease in FEV1 in a preliminary challenge. Inhaled SSA partially prevented both the early and late response, providing a protection with respect to placebo of 22 +/- 6% in the early phase and 23 +/- 9% in the late phase of the response. These values were lower (but not significantly) than those of LASA (41 +/- 9% and 39 +/- 11%, respectively). In a second group of patients, indomethacin failed to affect the early response, while LASA provided a protection of 31 +/- 7%. However, these two drugs were equally effective in reducing the late response (44 +/- 18% and 39 +/- 17% protection for LASA and indomethacin, respectively). In subjects with an early response, despite being ineffective in preventing allergen-induced bronchoconstriction, indomethacin blocked the allergen-induced increase in bronchial hyperresponsiveness measured 2 h after challenge. We conclude that inhaled salicylates, but not indomethacin, exert a protective activity against the early allergic response. This difference is not explained by the different pattern of cyclooxygenase inhibitory activity of these drugs.

Protective effect of inhaled lysine acetylsalicylate on allergen-induced early and late asthmatic reactions.

Conflicting results have been reported on the effect of non-steroidal antiinflammatory drugs on allergen-induced asthmatic responses. The aim of this study was to investigate the effect of inhaled lysine acetylsalicylate (LASA) on the early and late allergen-induced responses. We studied 16 patients with mild, stable asthma who had an early asthmatic response and 10 patients with a dual (early and late) response. Each patient underwent two challenges with a single dose of allergen assessed in a preliminary test, after inhalation of either 720 mg of LASA in 4 ml of saline solution or placebo, according to a randomized, double-blind protocol. Allergen-induced hyperreactivity to methacholine was measured in six patients from each of the early and the dual response groups 2 hours and 24 hours after the challenge, respectively. In the patients with early response, the maximum fall in FEV1 after challenge was 24% +/- 1% after inhalation of placebo and 14% +/- 2% after inhalation of LASA (p < 0.005). No protection was observed in four patients who received the drug orally instead of by inhalation. In the patients with a dual response, the maximum FEV1 decrease during the early response was 27% +/- 2% after placebo and 21% +/- 2% after LASA (p < 0.025). During the late response (between 3 and 8 hours), the maximum decrease in FEV1 was 28% +/- 4% after placebo and 16% +/- 4% after LASA (p < 0.005). In both groups allergen challenge caused a significant reduction in methacholine PD20 after treatment with placebo but not with LASA. Without allergen challenge, LASA had no effect on methacoline reactivity. We conclude that inhaled LASA significantly reduces both the early and the late asthmatic response to allergen challenge and that it prevents the allergen-induced airway hyperresponsiveness that follows these responses.

Attenuation of aspirin-induced bronchoconstriction by sodium cromoglycate and nedocromil sodium.

The protective activity of nedocromil sodium and of sodium cromoglycate against aspirin-induced asthma has never been investigated in controlled studies. Because it has been reported that aspirin-induced platelet-mediated cytotoxic activity in vitro is inhibited after treatment in vivo with nedocromil but not with cromoglycate, we investigated whether these compounds also exhibit a different protective activity against aspirin-induced bronchoconstriction. Ten patients with aspirin-induced asthma underwent three bronchial challenges with a single dose of lysine acetylsalicylate (LASA) that caused a decrease in FEV1 of 25% or more in a preliminary dose-response test 30 min after inhalation of 4 mg nedocromil sodium, 10 mg sodium cromoglycate, or placebo. FEV1 and SRaw were recorded at intervals for 195 min. After placebo, LASA caused a maximal decrease in FEV1 of 42 +/- 4% of baseline. After cromoglycate and nedocromil the maximal decrease in FEV1 was reduced to 20 +/- 3% and 18 +/- 4%, respectively (p < 0.01 versus placebo for both treatments), without significant differences between the two treatments. Similar results were observed with SRaw. We conclude that, at the recommended therapeutic doses, sodium cromoglycate and nedocromil sodium are equally effective in attenuating aspirin-induced bronchoconstriction and that it is unlikely that platelet activation participates in the pathogenesis of aspirin-induced asthma.

Inhaled PGE2 prevents aspirin-induced bronchoconstriction and urinary LTE4 excretion in aspirin-sensitive asthma.

Bronchial overproduction of leukotrienes and inhibition of prostaglandin synthesis are involved in the pathogenesis of aspirin-induced asthma. We investigated whether inhaled prostaglandin E2 (PGE2) attenuates the response to bronchial challenge with lysine acetylsalicylate (LASA) and the associated increase in urinary leukotriene E4 (u-LTE4) in seven aspirin-sensitive subjects with asthma. Each subject performed two challenges with a single dose of LASA that caused a decrease in FEV1 of 20% or more in a preliminary test, immediately after inhaling 100 micrograms PGE2 in 4 ml saline or placebo, according to a randomized double-blind protocol. FEV1 was recorded at 30-min intervals for 4 h. u-LTE4 was measured by combined high-performance liquid chromatography enzyme immunoassay at 2-h intervals. After placebo, LASA caused an obstructive reaction in all patients, with a maximum decrease in FEV1 of 35 +/- 5% with respect to baseline. u-LTE4 rose from 911 +/- 261 picograms (pg)/mg creatinine at baseline to a maximum value of 2249 +/- 748 after challenge. Inhaled PGE2 provided almost complete protection in all patients. Baseline u-LTE4 was 883 +/- 243 pg/mg creatinine and did not change significantly during the test, reaching a maximum value of 864 +/- 290 (p < 0.05 versus placebo). These results confirm that PGE2 is highly effective in preventing aspirin-induced asthma and suggest that this effect is mediated by inhibition of sulfidopeptide leukotriene production.

Steroid-sparing effect of inhaled lysine acetylsalicylate and furosemide in high-dose beclomethasone-dependent asthma.

BACKGROUND: Inhaled lysine acetylsalicylate and furosemide exert a mutually potentiating protective activity on experimentally induced bronchoconstriction in asthma. OBJECTIVE: Our purpose was to investigate the clinical effectiveness of combined treatment of asthma with inhaled lysine acetylsalicylate and furosemide. METHODS: We performed a randomized, double-blind, crossover study in nine patients with chronic asthma requiring a high dose (2 mg/day) of inhaled beclomethasone for clinical control. Patients were treated with a combination of 720 mg inhaled lysine acetylsalicylate and 40 mg furosemide twice daily, or with matched placebo in addition to inhaled steroids. The dose of inhaled steroids was reduced by half every 15 days and eventually suspended unless a patient's respiratory condition worsened. RESULTS: During treatment with placebo, all patients had worsening of asthma at dosages of 1 or 0.5 mg/day beclomethasone (mean +/- SE, 833 +/- 83 micrograms/day). During combined treatment complete suspension of inhaled steroids in two patients and reduction to 0.5 to 0.25 mg in the remaining seven patients (mean, 250 +/- 72 micrograms/day) was achieved, with a mean reduction of 71% +/- 7%. Forced expiratory volume in 1 second, weekly peak expiratory flow rate, symptom score, and bronchodilator intake remained significantly better with combined treatment than with placebo. CONCLUSIONS: Treatment with inhaled lysine acetylsalicylate and furosemide allows a considerable sparing of inhaled steroids without significant side effects in patients with severe asthma.

The efficacy and safety of moguisteine in comparison with codeine phosphate in patients with chronic cough.

We conducted a multicentre, double-blind, parallel group study to compare the clinical efficacy of a new antitussive drug, moguisteine (100 mg t.i.d.), to that of a reference standard, codeine (15 and 30 mg, t.i.d.). Both drugs were given orally for a period of two days. A group of 119 patients (mean age 54 yrs; 61 females and 58 males) with chronic, dry or slightly productive cough, associated with various respiratory disorders (including chronic obstructive pulmonary disease, respiratory malignancies and pulmonary fibrosis) were enrolled at six participating centres. The percentage reduction in the number of morning coughs over a period of 6 h after the first administered dose compared to baseline assessment, was 21% with moguisteine (n = 39), 28% with codeine 15 mg (n = 38), and 29% with codeine 30 mg (n = 36). Differences between treatments were not significant. The percentage reduction in the number of nocturnal coughs per hour, after the last evening dose compared to baseline assessment, was 33, 46 and 52%, respectively. Subjective assessments (patients' visual analogue scale scores of cough frequency, cough intensity and sleep disturbance, and investigators' ranking of cough severity) indicated that there was a similar improvement in cough symptoms in all treatment groups. Adverse events were observed in two patients on moguisteine, three on codeine 15 mg, and five on codeine 30 mg. No event was serious, but discontinuation of treatment was required in two patients on codeine 30 mg. The results of our study suggest that moguisteine 100 mg t.i.d. is safe, and seems to have an antitussive activity similar to that of codeine 15-30 mg t.i.d.

Efficacy and tolerability of azithromycin versus amoxicillin/clavulanic acid in acute purulent exacerbation of chronic bronchitis.

An open randomized trial was conducted in 142 hospitalized and out-patients with acute purulent exacerbation of chronic bronchitis to compare the clinical efficacy and tolerability of azithromycin (n = 69) and amoxicillin/clavulanic acid (n = 73). Azithromycin (500 mg) was administered as a single dose for three days and amoxicillin/clavulanic acid (amoxicillin 875 mg-clavulanic acid 125 mg) was given b.i.d. for 8 days (8.16 +/- 1.18). Before therapy and 24-48 hours after the end of treatment, sputum culture (by positioning five orthodontal swabs at the opening of salivary gland ducts after a washing of the oral cavity with sterile saline solution to avoid oral contamination), chest X-rays, arterial blood gas analysis, trials of respiratory functions and routine blood tests were performed. In the azithromycin group (69 patients) the efficacy rate was 67.6% (46 patients: 34 cured and 12 improved); in 22 patients (32.4%) the treatment failed; 1 patient was not evaluated because of no follow-up. The overall efficacy rate in the amoxicillin/clavulanic acid group (73 patients) was 97.3% (71 patients: 60 cured and 11 improved); in 1 patient (1.4%) the treatment failed and 1 patient was a drop-out for side effects. All pathogens isolated before treatment were susceptible to the antibiotics administered. At the end of treatment microbiological efficacy was 67.1% in the azithromycin group and 98.6% in the amoxicillin/clavulanic acid group. The tolerability was judged good in both treatment groups. Side effects were observed in 1 patient treated with amoxicillin/clavulanic acid (diarrhea), which imposed interruption of treatment, and in 2 patients from the azithromycin group (gastralgia and biochemical laboratory tests: renal function).(ABSTRACT TRUNCATED AT 250 WORDS)

Time-limited protective effect of inhaled frusemide against aspirin-induced bronchoconstriction in aspirin-sensitive asthmatics.

Inhaled frusemide effectively prevents the bronchial obstructive response to allergens and to a number of nonallergic stimuli. In most of the experimental models in which it has been tested, the protective effect of frusemide has been evaluated for only a short time after administration. In aspirin-sensitive patients, acetylsalicylic acid causes an asthmatic reaction which typically lasts for 2 h or more after exposure. We investigated the presence and duration of the protective effect of inhaled frusemide against the bronchial response to aspirin in sensitive patients, using a specific inhalation challenge with lysine acetylsalicylate (LASA). In the first study, eight subjects with aspirin-asthma underwent two bronchial challenges with a single dose of lysine acetylsalicylate administered through a jet nebulizer, after treatment with 40 mg inhaled frusemide or placebo, according to a randomized, double-blind protocol. Forced expiratory volume in one second (FEV1) was monitored for 120 min after challenge. In the second study in eight patients, the protocol was modified by the use of a dosimeter for delivery of lysine acetylsalicylate, by reducing the dose of lysine acetylsalicylate to avoid intense reactions, and by extending the follow-up to 4 h. In the first study, after placebo, FEV1 gradually decreased, reaching a maximum decrement of 39 +/- 3% at 120min. Inhaled frusemide exerted a significant protection at all time-points, although this activity appeared to decrease with time. In the second study, after placebo, inhaled lysine acetylsalicylate caused a gradual decrease in FEV1, which reached a maximum decrement at 180 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of the antireactive, antiasthmatic effect of inhaled furosemide by inhaled lysine acetylsalicylate.

Nonsteroid antiinflammatory drugs interfere with the diuretic activity of furosemide, implying that this effect is at least partially dependent on renal prostaglandin synthesis. To investigate whether prostaglandin production could also modulate the bronchial antireactive activity of this diuretic drug, we investigated the effect of inhaled lysine acetylsalicylate (162 mg) and of furosemide (18 mg), alone and in combination, on the bronchial obstructive response to ultrasonically nebulized water in asthmatic patients. The study was also prompted by the conflicting results obtained in previous studies of oral nonsteroid antiinflammatory drugs. Fifteen asthmatic patients underwent bronchial challenge with a mist of ultrasonically nebulized distilled water at the same time of day on four occasions, 2-4 days apart, 15 min after premedication according to a double-blind, randomized protocol. After placebo, mean PD15 to water mist did not differ from a preliminary test (2.1 +/- 0.2 and 2.5 +/- 0.4 ml, M +/- SE, respectively). After lysine acetylsalicylate, mean PD15 rose to 5.0 +/- 0.7 ml (2.8 +/- 0.6 times higher than placebo); after furosemide, to 9.0 +/- 1.5 ml (4.4 +/- 0.9 times over placebo); and after the two drugs in combination, to 32.2 +/- 5.6 ml (16.3 +/- 3.0 times higher than placebo). Similar results were obtained with inhaled indomethacin, whereas sodium salicylate had no effect. These data indicate that the bronchial antireactive activity of inhaled furosemide is greatly enhanced by inhaled lysine acetylsalicylate through a mechanism which probably involves inhibition of the local synthesis of prostaglandins, and could have therapeutic implications.

Protective effect of inhaled piretanide on the bronchial obstructive response to ultrasonically nebulized H2O. A dose-response study.

Inhaled furosemide prevents the obstructive response to several bronchoconstrictor stimuli in asthma. To verify whether this protective effect is also shared by other loop diuretics, we investigated the effect of inhaled piretanide on the bronchial obstructive response to ultrasonically nebulized distilled water (UNW) in ten patients with moderate, stable asthma. In a randomized, single-blind dose-response study, each subject performed an UNW test immediately after nebulization of different doses of piretanide between 12 and 48 mg or placebo. The effect of a single 40-mg dose of inhaled furosemide was also investigated in six subjects. Piretanide caused a significant, dose-dependent increase in UNW PD20 with respect to placebo, corresponding to 0.6 +/- 0.2 doubling doses (mean +/- SE) after 12 mg, 1.3 +/- 0.2 after 24 mg, and 2.0 +/- 0.2 after 48 mg, and had a remarkable diuretic effect; 40 mg of furosemide increased UNW PD20 by 2.3 +/- 0.3 doubling doses (p < 0.01), but showed only a modest diuretic activity. These data indicate that inhaled piretanide is as effective as furosemide in preventing UNW-induced asthma, and this effect is unrelated to their diuretic potency.