Differences in relative efficiency of nebulisers for pentamidine administration

The study compared the pulmonary deposition of nebulised pentamidine when inhaled by way of different nebuliser systems by nine human-immunodeficiency-virus-positive patients with a history of previous Pneumocystis carinii pneumonia. Pentamidine, 50 mg or 300 mg, mixed with technetium-99m-labelled human serum albumin in a total volume of 3 ml, was administered by way of three jet nebulisers (System 22', 'System 22 Mizer', and 'Respigard II') operated with a gas flow of 6 l/min, and one ultrasound nebuliser ('Pulmosonic'). Pulmonary and non-pulmonary isotope deposition was measured for each apparatus and adverse effects and lung function tests were recorded. For both doses of pentamidine, the system 22 mizer produced the largest pulmonary isotope deposition and it was completed in the shortest time. Oropharyngeal and gastric deposition were least with the respigard II, which also caused the fewest adverse effects. The adverse effects were greatest with the system 22 mizer and pulmosonic and the higher pentamidine dose, which also caused significant reductions in measurements of pulmonary function. It is concluded that either the system 22 mizer or the respigard II should be used to administer nebulised pentamidine.