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

BACKGROUND AND OBJECTIVE

Dry powder mannitol has the potential to be used to enhance clearance of mucus in subjects with bronchiectasis. A reduction in FEV1 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 FEV1.

METHODS

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 FEV1 (PD15), and reactivity to mannitol, expressed as the % fall in FEV1 per mg of mannitol (response-dose ratio, RDR), are reported.

RESULTS

Subjects had an FEV1 of 68 ± 14% predicted, FVC of 97 ± 15% predicted and FEV1 /FVC of 71 ± 8%. They were mildly hypoxemic and the SpO2 was 95 ± 2%.They had a PD15 to mannitol of 235 mg (95% CI: 150-368 mg) and a RDR of 0.057% fall in FEV1 per mg (95% CI: 0.038-0.085). After pre-medication with SCG, PD15 increased (773 mg, P < 0.05) and RDR was reduced (0.013, P < 0.05). Pre-medication with eformoterol also resulted in an increased PD15 (1141 mg, P < 0.01) and a reduced RDR (0.009, P < 0.01). A small but significant decrease in SpO2 from baseline was noted after mannitol in the presence of SCG (P < 0.05).

CONCLUSIONS

Pre-medication with either SCG or eformoterol protects patients with bronchiectasis from developing a significant reduction in FEV1 after inhaling mannitol.