Deep-inspiration induced bronchoconstriction: a mechanism for beclomethasone aerosol intolerance

We studied 17 asthmatic patients complaining of coughing attacks, with or without asthma, when inhaling beclomethasone dipropionate aerosol (Becotide). Specific airway resistance (SRaw) was measured immediately after a maximal inspiration (MI) and after Becotide inhalation. The effect of a second inhalation of Becotide was measured 10 min after inhalation of salbutamol. MI and Becotide induced large, but transient, SRaw increases in all patients; in addition, the latter induced coughing reactions. After salbutamol pretreatment, Becotide inhalation did not increase SRaw but coughing usually persisted. In 6 patients only, the increase in SRaw after Becotide was larger than that observed after MI. In those patients, placebo and Aldecine (similar to Becotide except for the metering valve) aerosols induced SRaw increases similar to that observed after Becotide. These data suggest that Becotide-induced bronchoconstriction is mainly related to the deep breath required for the inhalation. Non-specific irritation of the airways was probably responsible for the additional bronchoconstriction noticed in some patients.