Ventilatory effects of aerosol gentamicin.

Bronchial provocation tests with gentamicin solution, 40 mg/ml, and with the drug vehicle solution alone were carried out in 29 subjects aged 19 to 66 years. There were 18 subjects with bronchial asthma, four with chronic bronchitis, four with primary carcinoma of the lung, and three with no chest disease. Two millilitres of each of the two test solutions was given to each subject, in duplicate, via a nebuliser driven by a Bird Mark 8 respirator. Ventilatory function (FEV1 and VC) was measured before and after each inhalation, and changes were expressed as percentage variations from baseline. Seven subjects, all from the asthmatic group, developed at least one immediate FEV1 fall of 20% or more. The reactions ranged up to 71% and occurred to both test solutions. There was a trend towards greater reactions to the vehicle. In two subjects pretreatment with salbutamol and sodium cromoglycate did not modify these reactions. In three of the seven, inhalation of 2 ml normal saline produced FEV1 falls of 25% to 30%, but these falls were not as great as each subject's reactions to the test solutions. Skin prick tests using the gentamicin solution were negative in all subjects. These results show that substantial obstructive reactions may occur in some asthmatic subjects after inhalation of gentamicin. The reactions appear to be non-immunological in nature and may be due to an irritant effect of the drug vehicle.