Acute effects of higher than customary doses of salmeterol and salbutamol in patients with acute exacerbation of COPD

Worsening of underlying bronchospasm maybe associated with acute exacerbations of chronic obstructive pulmonary disease (COPD). As airway obstruction becomes more severe, the therapeutic option is to add salbutamol, but not salmeterol, as needed to cause rapid relief of bronchospasm. Unfortunately, the most effective dosage of beta(2)-agonists may increase above that recommended during acute exacerbations. In this study, we compared the acute effects of higher than customary doses of salmeterol and salbutamol in 20 patients with acute exacerbation of COPD. A dose-response curve to salmeterol pMDI, 25 mug/puff, or salbutamol pMDI, 100 mug/puff, was constructed using I, I, and 2 puff's i.e., a total cumulative dose of 100 mug salmeterol or 400 mug salbutamol on 2 consecutive days. After baseline measurements, dose increments were given at 30-min intervals with measurements being made 25 min after each dose. Heart rate (HR) and pulse-oximetry (SpO(2)) measurements were then taken. Both salmeterol and salbutamol induced a large and significant (P<0.05) dose-dependent increase in FEVi [mean differences from baseline (L) = after 100 mug salmeterol: 0.174 (95% Cl: 0.112 to 0.237); after 400 mug salbutamol: 0.165 (95% Cl: 0.080 to 0.249)], in IC [mean differences from baseline (L) = after 100 mug salmeterol: 0.332 (95% Cl: 0.165 to 0.499); after 400 mug salbutamol: 0.281 (95% Cl: 0.107 to 0.456)] (Fig. 2), and in FVC mean differences from baseline (L) = after 100 mug salmeterol: 0.224 (95% Cl: 0.117 to 0.331); after 400 mug salbutamol: 0.242 (95% CI: 0.090 to 0.395)]. There was no significant difference between the FEVi values (P=0.418), the IC values (P=0.585), and the FVCvalue (P=0.610) after 100 mug salmeterol and 400 mug salbutamol. HR [mean differences from baseline (beats/min) = after 100 mug salmeterol: 3.15 (95% CI: -0.65 to 6.96); after 400 mug salbutamol: 2.30 (95% CI: -0.91 to 5.51)] and SpO(2) [mean differences from baseline (%) = after 100 mug salmeterol: -0.20 (95% CI: -1.00 to 0.60); after 400 mug salbutamol: -0.11 (95% CI: -1.00 to 0.79)] did not change significantly from baseline (P > 0.05).These data indicate that salmeterol is effective and safe in the treatment of acute exacerbation of COPD and support its use in this clinical condition. (C) 2002 Elsevier Science Ltd. All rights reserved.