BACKGROUND Preliminary evidence suggests that regular inhalation of nebulised
amiloride reduces sputum viscoelasticity, increases the clearance of sputum by mucociliary mechanisms and by coughing and reduces the rate of deterioration in lung function in patients with
cystic fibrosis. These effects depend on adequate delivery of
amiloride to the airways. This study was performed to quantify and compare pulmonary deposition of
amiloride produced by two different nebuliser systems. METHODS The pulmonary deposition of nebulised
amiloride (1 mg in 3 ml saline) was measured in eight patients with
cystic fibrosis when given via a jet (System 22 with CR 60 compressor) and an ultrasonic (Fisoneb) nebuliser.
Human serum albumin labelled with technectium-99m was used as an indirect marker for
amiloride and its deposition in the lung was detected with a
gamma camera. RESULTS
Amiloride inhalation caused no side effects or changes in spirometric indices. The mean (SD) total pulmonary
amiloride deposition was 57 (24) micrograms with the System 22 and 103 (53) micrograms with the Fisoneb nebuliser. Pulmonary deposition was completed more rapidly with the Fisoneb (4-5 minutes) than with the System 22 nebuliser (7-8 minutes) and the Fisoneb was preferred by the patients. CONCLUSIONS Both nebulisers appeared to deliver adequate amounts of
amiloride to the lungs, but treatment with the Fisoneb nebuliser was quicker, more efficient, and more acceptable to the patients. Of the two nebulisers assessed, the Fisoneb would be preferred for clinical trials.