Introduction: During the 1970s, scientists suggested that the growing use of chlorofluorocarbons (CFCs) was contributing to depletion of the stratospheric ozone layer with potentially harmful results. A committee on the ozone layer organized the preparation of the Montreal Protocol. This protocol mandated the cessation of production and use of CFCs by January 1, 1996. The primary exemption to this ban is for the use of CFCs as propellants in metered dose inhalers (MDIs) for the treatment of asthma. Suitable replacement hydrofluoroalkane (HFA) propellants, such as HFA-134a, for use in MDIs have been identified. Albuterol, a selective beta-adrenergic agonist, currently widely available for inhalation asthma therapy, has been reformulated in HFA-134a (Proventil HFA).Objective: To compare the efficacy of Proventil HFA to Ventolin, Proventil, and placebo (HFA-134a) MDI in protecting asthmatic patients from exercise-induced bronchoconstriction.Methods: This was a randomized, single-blind, placebo-controlled, 4-period crossover study of asthmatic patients with documented exercise-induced bronchoconstriction. Twenty patients self administered two puffs of either Proventil HFA, Ventolin, Proventil or placebo, from an MDI, 30 minutes prior to performing a standardized exercise challenge at the study site. Spirometry was performed predose and 5, 10, 15, 30, 45, 60, 75, and 90 minutes after completion of the exercise challenge. Heart rate and blood pressure were measured just prior to spirometry and a 12-lead ECG was performed 15 minutes after completion of the exercise challenge for measurement of the QT corrected interval.Results: The primary efficacy variable was the smallest percent change from the predose FEV1 following exercise. The smallest percent change from predose FEV1 for Proventil HFA was 2.0 +/- 9.9 SD, similar to the 2.0 +/- 11.4 SD for Ventolin, and the 3.6 +/- 10.2 SD for Proventil. The smallest percent change from predose FEV1 for each of the active treatments was significantly different from placebo, -23.7 +/- 14.5. Twelve of the patients had a greater than or equal to 20% fall in FEV1 post-exercise with placebo pretreatment, but only 1, 1, and 0 had greater than or equal to 20% FEV1 falls after treatment with Proventil HFA, Ventolin, and Proventil respectively. Changes in heart rate, blood pressure and QT corrected interval were similar for the three active treatments following exercise.Conclusions: Proventil HFA provides protection against exercise-induced bronchoconstriction comparable to Ventolin and Proventil and protection superior to placebo. Proventil HFA has a safety profile similar to Ventolin when used to prevent exercise-induced bronchoconstriction.

BACKGROUND/OBJECTIVE:The purpose of this study was to determine whether the addition of extended-release theophylline to the daily treatment regimen of inhaled beta 2-agonist users would result in decreased use of beta 2-agonist while maintaining similar efficacy for treatment of asthma.METHODS:This was a single-blind, multicenter (six sites) study. Sixty-one patients with a history of mild-to-moderate asthma treated with inhaled beta 2-agonist were randomized to treatment with Theo-24 (anhydrous extended-release capsules) plus inhaled beta 2-agonist or placebo plus beta 2-agonist. Patients kept daily symptom diaries, measured peak flow rates, recorded puffs of inhaled beta 2-agonist, and adverse events during a 4-week treatment period.RESULTS:Fifty-five patients were included in the efficacy analysis. The primary efficacy variable in this study was the mean number of puffs (adjusted for baseline differences) of beta 2-agonist inhaled per day. In this study, the addition of theophylline to the daily regimen of inhaled beta 2-agonist for 4 weeks significantly reduced the total daily dose of inhaled beta 2-agonist at weeks 3 and 4 of treatment compared with placebo. The differences were significant at the P < .05 level. For patients in the theophylline group, the number of puffs decreased from an unadjusted mean of 9.81 at baseline to an adjusted mean of 6.78 after 4 weeks of treatment compared with 9.91 at baseline and 8.17 for the placebo group. There were no unexpected or serious adverse events.CONCLUSIONS:In this study, the addition of once daily, extended-release theophylline to the daily regimen of inhaled beta 2-agonist for 4 weeks significantly reduced the total daily dose of inhaled beta 2-agonist at weeks 3 and 4 of treatment compared with placebo, while maintaining acceptable asthma symptom scores.