High inhaler resistance does not limit successful inspiratory maneuver among patients with asthma or COPD

ABSTRACT

Introduction

There has been an active discussion on the sustainability of inhaler therapy in respiratory diseases, and it has cast a shadow on pMDIs which rely on propellant with high global warming potential (GWP). DPIs offer a lower GWP and effective alternative, but there has been concern whether all patients can generate sufficient inspiratory effort to disperse the drug. This review focuses on airflow resistance of DPIs and its clinical relevance.

Areas covered

For this narrative review, we searched the literature for studies comparing flow patterns with different devices. We also included a section on clinical trials comparing reliever administration with DPI, pMDI with spacer, and nebulizer during exacerbation.

Expert opinion

The evidence supports the efficacy of DPIs irrespective of respiratory condition or age of the patient even during acute exacerbations. Air flow resistance does not limit the use of DPIs and the patients were able to generate sufficient inspiratory flow rate with almost any device studied. None of 16 identified clinical trials comparing reliever administration via DPIs to other types of devices during exacerbation or bronchial challenge showed statistically significant difference between the device types in FEV1 recovery. DPIs performed as well as other types of inhaler devices even during asthma or COPD exacerbation.

KEYWORDS:

• Inhaler
• peak inspiratory flow rate
• dry powder inhaler
• metered dose inhaler

Article highlights

• There is an increasing pressure to shift from pressurised metered dose inhalers to more environmentally friendly devices.

• Inhaler resistance is a designed property of the inhaler.

• Nearly all patients can generate sufficient inspiratory flow for the use of DPIs.

• Exacerbation of obstructive pulmonary diseases do not seem to limit the use of DPIs.

• During exacerbations DPIs performed as well as pMDIs and nebulizers in clinical trials.

This box summarizes key points contained in the article.

Glossary of terms and abbreviations

∆p, pressure change over the inhaler; API, active pharmaceutical ingredient; COPD, chronic obstructive pulmonary disease; da, Aerodynamical diameter; GWP, global warming potential; DPI, dry powder inhaler; IF, impaction factor; PIP, peak inspiratory pressure drop; P, power of the airflow; PIF, Peak inspiratory flow; PIP, Peak inspiratory pressure; pMDI, pressurized metered dose inhaler; Q, volumetric airflow; R, inhaler resistance

Declaration of interest

V Vartiainen has received lecture and consultant fees from Orion Pharma and was an employee of Orion Pharma during 2019–2021. F Lavorini has received grants for research or fees for speaking and advisory boards from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Menarini International, Novartis, Orion, and Trudel Medical International. A Murphy has received funding for research studies, consultancy agreements, and honoraria for presentations from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Orion, Sanofi, and Trudell Medical International. K Rabe has received Consultancy and speaker fees from Boehringer Ingelheim, AstraZeneca, Novartis, Chiesi, Sanofi, Roche, Regeneron, and Orion as well as grants from Boehringer Ingelheim and AstraZeneca. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have received an honorarium from Expert Opinion on Drug Delivery for their review work, but have no other relevant financial relationships to disclose.

Additional information

Funding

Medical writing of this manuscript was funded by Orion Pharma (Espoo, Finland). V Vartiainen was the medical writer of this manuscript.