Objective: To evaluate the effectiveness and onset of action of formoterol delivered by dry-powder inhaler in reversing methacholine-induced bronchoconstriction. Methods: Patients presenting a drop in forced expiratory volume in one second > 20% after methacholine inhalation were included. A total of 84 patients were evaluated. All of the participating patients presented respiratory symptoms of unknown origin, which were being investigated. The patients were randomized to receive 200 µg of spray fenoterol (n = 41) or 12 µg of dry-powder inhaler formoterol (n = 43), both administered in order to achieve immediate reversal of methacholine-induced bronchoconstriction. We evaluated the decrease in forced expiratory volume in one second (in relation to the baseline value) after methacholine challenge and the dose of methacholine required to provoke a drop of 20% in forced expiratory volume in one second, as well as the increase in forced expiratory volume in one second (in relation to the baseline value) at five and ten minutes after bronchodilator use. Results: There were no significant differences related to gender, age, weight, height or dose of methacholine required to provoke a drop of 20% in forced expiratory volume in one second. Nor were there any significant differences in terms of baseline or post-methacholine forced expiratory volume in one second. In the fenoterol group, the mean postbronchodilator increase in forced expiratory volume in one second increase was 34% (at five minutes) and 50.1% (at ten minutes), compared with 46.5% (at five minutes) and 53.2% (at ten minutes) in the formoterol group. Conclusion: The bronchodilator effect of formoterol at five and ten minutes after methacholine-induced bronchoconstriction was similar to that of fenoterol. Despite being a long-acting bronchodilator, formoterol also has a rapid onset of action, which suggests that it could be employed as a relief medication in cases of bronchoconstriction occurring during asthma attacks.

Keywords: Asthma; Formoterol; Fenoterol; Inhalation therapy; Bronchodilation, Methacoline

Background: Short-acting b2 agonists delivered by metered-dose inhaler (MDIs) are the drugs usually used for the reversal of methacholine-induced bronchoconstriction. The b2 agonists that are delivered by dry-powder inhaler (DPI) can be an efficacious option. Objective: To evaluate the effectiveness and speed of action of salbutamol delivered by DPI (Pulvinal; Butoventâ), in comparison to salbutamol delivered by MDI, in reversing methacholine-induced bronchoconstriction. Method: Sixty successive methacholine-induced bronchoconstriction patients who presented a decrease of at least 20% in forced expiratory volume (FEV1) were evaluated prospectively. Of these 60 patients, we randomized 30 (first group) to receive 200 mcg of salbutamol by MDI and 30 (second group) to receive 200 mcg of salbutamol by DPI (Pulvinal). Both drugs were administered with the objective of reversing bronchoconstriction during the final phase of a bronchoprovocation test. The FEV1 values obtained at 1 and 5 minutes after bronchodilator administration were evaluated. Results: The groups were comparable in gender distribution, age, weight, dose level provoking a 20% drop in FEV1 (first group: 1.3 mg; second group: 1.19 mg; p = 0.79) and post-methacholine FEV1 (first group: 2.03 l; second group: 1.99 l; p = 0.87), with no statistically significant differences between the two groups. In the first group (MDI), the mean increase in FEV1 was 16.2% (at 1 minute) and 22.2% (at 5 minutes), and in the second group (DPI) it was 17% (at 1 minute) and 23.6% (at 5 minutes). There was no statistically significant difference between the groups (p = 0.8). Conclusion: The b2-agonists delivered by DPI (Pulvinal) present the same bronchodilator efficacy and speed of action as do those delivered by the more traditional MDI method.

Keywords: Asthma. Bronchodilator agents/administration & dosage. Albuterol/administration & dosage. Methacholine chloride/administration & dosage. Respiratory therapy/methods. Administration, inhalation/methods. Prospective studies.

Objective: To compare the bronchodilatory effect of salbutamol delivered by metered-dose inhaler connected to spacers with and without previous antistatic treatment. Design: Prospective, randomized, open, crossover study. Setting: Outpatients from The Pulmonary Clinic of Hospital Júlia Kubitschek-FHEMIG, Belo Horizonte, Minas Gerais, Brazil. Patients and methods: Eleven patients, with stable mild to moderate asthma were randomized to four inhalation tests of 100 mg of salbutamol: (A) open mouth, (B) non antistatic small volume spacer (50 ml), (C) antistatic small volume spacer (50 ml) and (D) antistatic Fisonair® (750 ml). The antistatic treatment consisted in soaking the spacer in a solution of water and detergent for ten minutes and letting it to drip dry without rinsing. Main outcome measure: The peak expiratory flow (PEF) variation 15 minutes after each test in absolute, % of predicted and % of baseline values. Results: The median (Min-Max) PEF absolute variation was 25 (5-85), 40 (0-70), 70 (25-83) and 60 (15-90) l/min for tests A, B, C and D, respectively. The median PEF % baseline variation was 7.6, 11.0, 15.0, 13.3, and median PFE % predicted variation was 6.0, 8.7, 12.7 and 10.7 for tests A, B, C and D, respectively. The results of tests C and D were significantly superior to those of tests A and B (p < 0.01) based on the three methods evaluated. There was no significant difference between the results of tests C and D. Conclusion: The antistatic treatment of a small volume spacer device using a solution of water and detergent can improve the antiasthmatic effect of inhaled drugs delivered by metered-dose inhaler, as occurred with the salbutamol in this study. This fact can be more relevant concerning the treatment with inhaled steroids for asthma.

Keywords: Asthma. Respiratory therapy. Aerosols. Albuterol.

Summary: b-agonists are considered the agents of first choice for the treatment of asthmatic symptoms and are usually available for aerosol administration. Its propellants damage the ozone layer and are often not used properly by the patients. Turbuhaler seems a better alternative since it does not present these inconveniences. In Brazil, it has been recently introduced. Purpose: Compare salbutamol aerosol (SA) to terbutaline turbuhaler (TT) in relation to technical use, bronchodilation and adverse effects in outpatients with mild-obstruction asthma (PFR ³ 60 and < 80% predicted). Material and methods: Open, parallel randomized study performed in each arm of 20 patients (SA: 200 mg and TT: 500 mg). After 30 minutes, a second dose was given if PFR was not 15% or 30 L/min greater than the initial one; a second dose was also delivered if PFR was not greater than 80%. All patients were instructed on how to use both devices. Results: Clinical improvement and increase in PFR were similar in both groups (SA 69.5 vs. TT 58.1 L/min, p > 0.05). A second dose was given to 13 patients (SA 6 and TT 7) with similar results. Errors in the usage were observed in all 20 patients of group SA vs. 11 patients in group TT (p < 0.05). Adverse effects were more frequent with TT - 9 patients - due to its unpleasant taste. Fifteen patients of group TT and with previous experience with SA considered turbuhaler easier. Conclusions: 1) administration by the patient is easier with turbuhaler than with SA; 2) bronchodilation is not different with SA 200 mg and TT 500 mg; 3) unpleasant taste was noted only in group TT (50% of the patients).

Keywords: Asthma. Salbutamol aerosol. Terbutaline Turbuhaler.