Clinical effect of high inhalation flow from a fluticasone diskhaler in chronic asthma]

The optimal inhalation flow of dry powder formula fluticasone dipropionate (DFP) is not known. This study investigated the clinical effects of inhaling a flow of DFP. A randomized cross-over trial was applied to 13 patients with chronic persistent asthma. After a 2-week run-in period using the current dose of beclomethasone from a metered dose inhaler (BDP-run), BDP was replaced with an equipotent amount of DFP. The patients entered either an 8-week run with high-flow (> 100 L/min) inhalation followed by a 4-week run with medium-flow (70 L/min) (HM group) or a medium-flow run followed by a high-flow run (MH group). The peak inhaling flow from DFP was measured daily. The mean of the inhalation flow in the high-flow run (111.4 +/- 3.6 (SE) L/min) was significantly higher than that (77.3 +/- 0.6 L/min) in the medium-flow run. In both groups, morning and evening peak expiratory flows (PEFs) increased in the first week of change from BDP to DFP, peaking in the first 8-week run, then maintained this level until the end of the following 4-week run. When PEFs in the last week of the 3 runs were compared, those during the DFP-run of either flow were significantly larger than those during the BDP-run, but the PEFs during the high-flow and medium-flow runs were not significantly different. The asthma symptoms also improved with a change from BDP to DFP, but the symptoms did not change with a change in the inhalation flow rate. An inhaled flow of up to 111 L/min is acceptable in terms of clinical efficacy for the use of DFP.