Bronchodilator responses to salbutamol using diskhaler versus metered-dose inhaler

Area of Science:

• Pharmacology
• Respiratory Medicine
• Clinical Trials

Background:

• Standard dosage for salbutamol via metered-dose inhalers (MDIs) is 200 mcg.
• Manufacturers recommend 400 mcg for diskhaler delivery, differing from MDI recommendations.
• The efficacy of higher diskhaler doses requires investigation.

Purpose of the Study:

• To compare the dose-response of salbutamol delivered via diskhaler (200 mcg vs. 400 mcg) against a 200 mcg MDI dose.
• To evaluate the clinical and statistical significance of different salbutamol doses and delivery devices in mild/moderate asthmatics.

Main Methods:

• Partially double-blind, placebo-controlled, crossover study design.
• Involved 12 adult patients with mild to moderate asthma.
• Measured peak expiratory flow rate (PEFR) increments after administration of salbutamol via diskhaler (400 mcg and 200 mcg) and MDI (200 mcg), compared to placebo.

Main Results:

• No clinically or statistically significant differences in PEFR increments were observed between the 400 mcg and 200 mcg diskhaler doses.
• Both active treatments showed minimal differences in PEFR increments compared to placebo: 400 mcg diskhaler (10 L/min), 200 mcg diskhaler (20 L/min), and 200 mcg MDI (15 L/min).
• Confidence intervals (95% CI) for median differences were [ -10, 50], [0, 50], and [0, 30] respectively.

Conclusions:

• The manufacturer's recommendation of 400 mcg salbutamol via diskhaler is not supported by evidence compared to a 200 mcg dose.
• Diskhalers can be a viable alternative to MDIs, particularly for patients with suboptimal MDI technique.
• Further research may be needed to fully elucidate optimal dosing strategies for different inhaler devices.