A system for treating or providing prophylaxus against a pulmonary infection is disclosed comprising: a) a pharmaceutical formulation comprising a mixture of free antiinfective and antiinfective encapsulated in a lipid-based composition, and b) an inhalation delivery device. A method for providing prophylaxis against a pulmonary infection in a patient and a method of reducing the loss of antiinfective encapsulated in a lipid-based composition upon nebulization comprising administering an aerosolized pharmaceutical formulation comprising a mixture of free antiinfective and antiinfective encapsulated in a lipid-based composition is also disclosed.