The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.

Letter to the editor

Editor, Australian Prescriber has published information about fluticasone propionate in its New Drugs section (Aust Prescr 1994;17:74). This stated that caution is advised when changing from the dry powder to the aerosol form of fluticasone; however, clinical trials do not support this statement.1,2

Each inhalation from the metered dose inhaler is half the strength from the corresponding Diskhaler. Therefore, for a given dose, the patient inhales two puffs from the inhaler or the contents of one blister.

Clarification that the devices are clinically equivalent, dose for dose, would be appreciated as this may help to avoid confusion among prescribers regarding the interchangeability of these devices.

Catherine Lewis
Allen & Hanburys
Boronia, Vic.

Editor's comment

Caution was advised when the new drug comment was prepared because the bio availability of the dry powder and the aerosol may be different. The approved product information for fluticasone states 'Doses delivered by the dry powder inhalers and metered dose inhalers may not have the same systemic bioavailability; however, there is no difference in clinical efficacy between the inhalers in controlled studies'.

Examination of the quoted papers reveals that one was a conference presentation and the other was in collaboration with Glaxo Group Research. These short term studies (4-6 weeks) showed that each preparation is effective. Although any differences in bioavailability are probably insignificant, neither study had a crossover design to confirm that the formulations are interchangeable.

References

  1. Lundback B, Alexander M, Day J, Hebert J, Holzer R, Van Uffelen R, et al. Evaluation of fluticasone propionate (500 mcg/day) administered either as a dry powder via a Diskhaler inhaler or pressurized inhaler and compared with beclomethasone dipropionate (1000 mcg/day) administered by pressurized inhaler. Respir Med 1993;87:609-20.
  2. Dahl R. The safety and efficacy of fluticasone propionate200 mcg daily given via the Diskhaler inhaler as compared with the pressurized metered dose inhaler in adult asthma. Clin Exp Allergy 1993;23(1 Suppl):81S.