Sodium cromoglycate and eformoterol attenuate sensitivity and reactivity to inhaled mannitol in subjects with bronchiectasis

Dry powder mannitol has the potential to be used to enhance clearance of mucus in subjects with bronchiectasis. A reduction in FEV has been recorded in some subjects with bronchiectasis after inhaling mannitol. The aim of this study was to investigate if pre-medicating with either sodium cromoglycate (SCG) or eformoterol could inhibit this reduction in FEV. A double-blind, placebo-controlled, randomized cross-over study was conducted. Lung function and airway response to mannitol was assessed on a control day and then re-assessed after pre-medication with placebo, SCG and eformoterol in nine subjects. Sensitivity to mannitol, expressed as the dose required to induce a 15% fall in FEV (PD), and reactivity to mannitol, expressed as the % fall in FEV per mg of mannitol (response-dose ratio, RDR), are reported. Subjects had an FEV of 68 ± 14% predicted, FVC of 97 ± 15% predicted and FEV/FVC of 71 ± 8%. They were mildly hypoxemic and the SpO was 95 ± 2%.They had a PD to mannitol of 235 mg (95% CI: 150-368 mg) and a RDR of 0.057% fall in FEV per mg (95% CI: 0.038-0.085). After pre-medication with SCG, PD increased (773 mg, P < 0.05) and RDR was reduced (0.013, P < 0.05). Pre-medication with eformoterol also resulted in an increased PD (1141 mg, P < 0.01) and a reduced RDR (0.009, P < 0.01). A small but significant decrease in SpO from baseline was noted after mannitol in the presence of SCG ( P < 0.05). Pre-medication with either SCG or eformoterol protects patients with bronchiectasis from developing a significant reduction in FEV after inhaling mannitol. A reduction in FEV is recorded in a significant minority of patients with bronchiectasis following inhalation of mannitol. This study reports that pre-medication with a standard dose of either sodium cromoglycate or eformoterol can protect this patient group from developing mannitol induced bronchospasm.