ABSTRACT
<b><i>Abstract</i></b><br><b>Objective</b> : Laninamivir Octanoate (LO) is a novel anti-influenza drug administered by inhalation only once administration, and with a very simple dosage adjustment regimen. Conversely, inhalation might be expected to fail in some groups of patients, particularly the very young and very elderly because of poor inhalation technique. Therefore, we undertook a study to investigate the success and failure rates of the dry powder inhalation formulation of LO.<br><b>Methods</b> : We observed 159 patients who were prescribed LO. Pharmacists observed the administration technique after explaining how to inhale the drug. Success was defined as patients who could inhale the drug without a problem. Failure was defined as those patients who were judged to have inhaled less than 75％ of the drug. We also examined the success rate between pharmacies and the success and failure rates according to age.<br><b>Results</b> : A 4-years-old patient was the youngest to fail LO therapy whereas a 5-years-old patient was the youngest to succeeded with the therapy. The success rate did not differ significantly between pharmacies. The success rate was 88.9％ in patients under the age of 9 years, but which was significantly lower compared with 97.9％ in the group of patients over 10 years of age.<br><b>Conclusion</b> : This survey revealed that many cases of inhalation failure of LO anti-influenza therapy occur below the age of 9 year.