Inhaled mannitol in cystic fibrosis

Inhaled mannitol has recently been given fast-track status as an investigational drug to treat the lung manifestations of cystic fibrosis. It seems to work in a similar way to nebulized hypertonic saline, osmotically inducing water flux into the bronchial lumen, thereby increasing the hydration of airway mucus, which can then be cleared more effectively by mucociliary clearance and coughing. Short-term studies have shown good tolerability and improvements in lung mucociliary clearance. Longer-term studies studying end points of clinical relevance are ongoing. This article assesses its likely future role in cystic fibrosis.