Therapeutic equivalence and acceptability of two multidose powder inhalers in the treatment of asthma.

Background: Problems in using conventional inhalation aerosols, in addition to environmental reasons, have driven development of the dry powder inhalers.

Objective: To compare therapeutic equivalence and acceptability of two dry powder inhalers, Easyhaler (EH) and Diskhaler (DH), in the delivery of beclomethasone dipropionate (BDP) in the treatment of asthma.

Methods: Adult asthmatics (n = 185), previously treated with inhaled steroids, were recruited in this open parallel-group study. After a run-in period of 2 weeks during which the patients inhaled 800 microg/day of BDP via DH, the patients were randomly allocated into three groups: EH 200 group (62 patients) using EH 200 microg/dose inhaler (1 inhalation q.i.d.), EH 400 group (62 patients) using EH 400 microg/dose inhaler (1 inhalation b.i.d.), and DH group (61 patients) using DH 200 microg/dose inhaler (1 inhalation q.i.d.) for 12 weeks. The primary outcome variables were PEF and FEV(1).

Results: The 95% CI for treatment difference in morning PEF between the EH 200 and DH groups was -16 to 23 litres/min and between the EH 400 and DH groups -18 to 21 litres/min. There was an increase in the morning PEF of 13 litres/min (p < 0.05) in the EH 200 group, and 9 and 11 litres/min in the DH and EH 400 groups. No differences between the groups were seen in the lung function parameters, in the symptom scores, in the use of rescue medication or in the incidence of adverse events. The treatments had no effects on morning cortisol levels. The patients in the EH groups compared the inhalers by using an 11-item questionnaire. In 8 questions the majority of the patients rated EH superior to DH.

Conclusion: The tested inhalers were therapeutically equal. However, based on the acceptability data, the EH was better accepted by the patients than DH.