Is Spiriva (tiotropium) a DPI or MDI?

Spiriva (Tiotropium) Delivery Device: DPI and MDI Options

Spiriva (tiotropium) is primarily available as a dry powder inhaler (DPI) through the HandiHaler device, but is also available as a soft mist inhaler (SMI) through the Respimat device, which functions similarly to an MDI but with important differences.

Available Delivery Systems for Tiotropium

HandiHaler (DPI)

• Tiotropium was originally developed and most widely used as a dry powder inhaler (DPI) delivered through the HandiHaler device 1
• The recommended dosage is 18 micrograms once daily 2
• Requires active inhalation effort from the patient to deliver medication
• Breath-actuated system that delivers medication as a dry powder 3

Respimat (Soft Mist Inhaler)

• More recently developed delivery system for tiotropium 1, 4
• Delivers 5 micrograms (2 puffs of 2.5 mcg) once daily 2, 5
• Uses a novel delivery system creating a soft mist rather than a dry powder 1
• Not technically an MDI (metered dose inhaler) as it doesn't use propellants but creates a mechanical soft mist 6
• Provides more efficient drug deposition throughout the respiratory tract 6

Clinical Differences Between Delivery Systems

Efficacy Comparison

• The TIOSPIR trial demonstrated that tiotropium Respimat was noninferior to tiotropium HandiHaler in terms of all-cause mortality 4
• Both delivery systems provide similar efficacy in improving lung function, reducing exacerbations, and improving quality of life 4
• The Respimat allows for a lower dose (5 mcg vs 18 mcg in HandiHaler) due to improved lung deposition 4

Safety Considerations

• Initial concerns about increased mortality risk with Respimat have been refuted by more recent evidence 6
• Both delivery systems have similar safety profiles with anticholinergic side effects (primarily dry mouth) being most common 2, 7
• No significant differences in serious adverse events between the two delivery systems 1

Patient Usability

• HandiHaler requires more coordination and proper inhalation technique 3
• Respimat may be easier to use for some patients, particularly those with limited inspiratory capacity 6
• In comparative studies, patients had fewer errors using the HandiHaler compared to traditional MDIs 3

Clinical Implications for Device Selection

Patient Factors to Consider

• Inspiratory flow capacity: Patients with very low inspiratory flow may benefit from Respimat
• Manual dexterity: HandiHaler requires loading capsules which may be difficult for some patients
• Preference: Some patients may prefer one device over the other
• Previous device experience: Familiarity with similar devices may influence proper technique

Practical Considerations

• Once-daily dosing with both devices improves adherence compared to multiple daily dosing regimens 2
• HandiHaler has been available longer and may be more familiar to patients and providers
• Respimat delivers medication as a slow-moving mist that may be easier to coordinate with inhalation 4

Conclusion

Both the HandiHaler (DPI) and Respimat (soft mist inhaler) are effective delivery systems for tiotropium with similar clinical outcomes. The choice between them should be based on patient factors including inspiratory capacity, dexterity, and preference. The Respimat is not technically an MDI but functions similarly while providing a slower spray duration that may be easier for some patients to coordinate with inhalation.