Introduction Generic substitution of inhaler devices is a relatively new phenomenon. The best patient outcomes associated with generic substitution occur when prescribers obtain consent from their patients to prescribe a generic inhaler and also teach their patient how to correctly use the new device. To date, no prospective observational study has assessed the level of training required for general practitioners (GPs) to demonstrate correct inhaler technique using two dry powder inhaler devices delivering fixed-dose combination budesonide/formoterol therapy. This study aims to (1) determine the level of training required for GPs to master and maintain correct IT when using two different dry powder inhalers that are able to be substituted in clinical practice and (2) determine the number and types of errors made by GPs on each device and inhaler device preference at each training visit. Method A randomized, parallel-group cross-over study design was used to compare the inhaler technique of participants with a Spiromax(R) placebo device and a Turbuhaler(R) placebo device. This study consisted of two visits with each participant over a period of 4 +/- 1 weeks (visit 1 and visit 2). A total of six levels of assessment and five levels of training were implemented as required. Level 1, no instruction; level 2, following use of written instruction; level 3, following viewing of instructional video; level 4, expert tuition from the researcher; level 5/level 6, repeats of expert tuition from the researcher when required. Participants progressed through each level and stopped at the point at which they demonstrated device mastery. At each level, trained researchers assessed the inhaler technique of the participants. Participants were also surveyed about their previous inhaler use and training. Results In total, 228 GPs participated in this study by demonstrating their ability to use a Turbuhaler(R) and a Spiromax(R) device. There was no significant difference between the proportion of participants who demonstrated device mastery with the Turbuhaler(R) compared with the Spiromax(R) at level 1, (no instruction), (119/228 (52%) versus 131/228 (57%), respectively, n = 228, p = 0.323 (McNemar's test of paired data). All but one participant had demonstrated correct inhaler technique for both devices by level 3(instructional video). There was a significant difference between the proportion of participants who demonstrated maintenance of device mastery with the Turbuhaler(R) compared with the Spiromax(R) at visit 2, level 1 (127/177 (72%) versus 151/177 (85%) respectively, p = 0.003; McNemar's test of paired data). All but two participants achieved device mastery by level 3, visit 2. More participants reported previous training with the Turbuhaler(R) than with Spiromax(R). Discussion This study demonstrates that GPs are able to equally demonstrate correct use of the Turbuhaler(R) and Spiromax(R) devices, even though most had not received training on a Spiromax(R) device prior to this study. The significance of being able to demonstrate correct technique on these two devices equally has ramifications on practice and supported generic substitution of inhaler devices at the point of prescribing, as the most impactful measure a GP can take to ensure effective use of inhaled medicine is the correct demonstration of inhaler technique.
