Background: Inhaled albuterol is most commonly self-administered by patients using a pressurized metered-dose inhaler (pMDI) but patients often have difficulty using the device. Dry powder devices such as the multi-dose, inspiratory flow driven inhaler (Turbuhaler) are often better handled by patients.
Objective: We sought to compare the efficacy and tolerability of 100 micrograms of albuterol delivered by a multi-dose, inspiratory flow driven inhaler (Turbuhaler) to a standard dose (200 micrograms) delivered by a pMDI (Ventolin) in chronic reversible obstructive airways disease.
Method: In 6 centers, we studied 37 adults [19 men and 18 women, mean age 39 +/- 12 years; mean baseline forced expiratory volume in one second (FEV1) 72 +/- 13% (% predicted)] with stable but symptomatic reversible obstructive airways disease as demonstrated by 15% or greater increase in FEV1 following two puffs (200 micrograms) albuterol by pMDI. The crossover design comprised a 1-week run-in and two 2-week treatment periods separated by a 1-week washout. At the start and end of each treatment period, FEV1 was measured at the clinic. Patients self-administered albuterol 100 micrograms (2 x 50 micrograms) via Turbuhaler or 200 micrograms (2 x 100 micrograms) via pMDI in a double-blind fashion four times daily. Morning and evening peak expiratory flow (PEF) was noted daily. All non-study bronchodilators were withheld while open-label albuterol pMDI was offered for rescue.
Results: Of the 37 patients, 30 used inhaled steroids in constant doses throughout the study, one used inhaled cromoglycate and six used no anti-inflammatory therapy. There was no difference between treatment periods in morning PEF, diurnal fluctuation in PEF, increase in PEF following study drug, baseline FEV1 and FEV1 increase following study drug. Although there was no difference in symptom scores between treatments, the use of rescue beta 2-agonist was slightly but significantly higher during the Turbuhaler treatment period (1.34 versus 1.08 inhalations/ day, P = .04). Compliance with study drug was slightly but significantly lower during the Turbuhaler treatment period (87 versus 95%) such that the total number of beta 2-agonist puffs inhaled (scheduled plus rescue) was similar between treatments. With regard to adverse events, both treatments were well tolerated.
Conclusions: These results suggest that the efficacy and tolerability of albuterol 100 micrograms qid inhaled via Turbuhaler is similar to albuterol 200 micrograms qid, inhaled via pMDI in stable reversible obstructive airways disease.