Analysis of the factors associated with drugs remaining in the Diskhaler following inhalation of fluticasone propionate

: Because it is well known that drug remains in the fluticasone propionate Diskhaler (FP-DH) following a single inhalation, the following patient information is recommended. "Please inhale more than once or twice if any drug remains in the device after inhalation". It is believed the inspiratory flow rate of the individual patient has an influence on the amount of drug that remains in the device. If the dosing performance of FP-DH is dependent on inspiratory effort, establishment of a method of inhalation that makes it independent of inspiratory flow rate is important in clinical practice. In the present study, we investigated the influence of various methods of inhalation of drug remaining in the FP-DH. No significant differences were observed regarding the drug remaining in the device among the inhalation times examined (range, 0.5-2.5 s) or the number of inhalations (range, 1-3 times). On the other hand, the amount of drug remaining in the device did decrease by tapping the device before the second inhalation. The results suggest that the amount of drug remaining in the device can be decreased by tapping the device after the first inhalation if the patient's inspiratory flow rate is low.