Despite major improvements in drug output of new nebulizers and differences between nebulizers [1], doses of albuterol nebulizing therapy of hospitalized COPD‐patients has not changed in the last decades. The objective was to determine the optimal dose in the current setting according to a standardized protocol (10 min at flow 8 l min−1, MICRO MIST nebulizer, Hudson RCI). After a washout of bronchodilators patients nebulized 5 mg (group A; n=21. FEV1=47.4 ± 2.9% predicted; Tiffeneau=48.1 ± 2.5%) or 10 mg (group B; n=21, FEV1=50.5 ± 3.8% predicted; Tiffeneau=49.5 ± 3.4%) albuterol (t=−10 to 0 min). Pulmonary function (PF) (FEV1, FVC, Tiffeneau), dyspnoea (modified Borg scale) and heart‐frequency (HF), blood pressure (BP), breathing‐frequency (BF), serum potassium (K), fingertremor, QTc‐interval, were measured at t=−30, 10, 30, 60, 120, 240 min. Charcoal was administered to prevent gastrointestinal absorption (t=−10; 10 min (5 g) and 60 min (10 g). Pharmacodynamic (PD)‐effects, relative to baseline, and correlation between effects, severeness of COPD and patient characteristics were analysed. FEV1 and FVC increased significantly (FEV1: (A) 10–120 min; (B) 10–240 min; Figure 1), leaving Tiffeneau unchanged. FVC at t=10 is significantly greater for group B compared to A (P=0.009). PD‐parameters (Table 1) showed significant changes. Figure 1  Mean FEV1, FVC in groups A and B. ⧫▵ FEV, A, ▪▵ FEV, B, ▴▵ FVCA, *▵ FVCB. PD‐parameter differences relative to t=−30 min, group A and B t=10 t=30 t=60 t=120 t=240 ΔHF (beats min−1)A4.1±1.5^6.0±1.9*^7.8±2.0*8.5±1.9*4.2±1.4*B12.5±2.6*15.1±3.0*14.0±2.4*10.0±2.0*7.6±2.3*ΔQTc (ms)A8.3±4.0*^6.5±9.0^28.2±8.0*14.3±6.0*7.3±4.7B26.0±6.0*30.7±6.0*20.0±6.8*16.5±5.6*18.0±6.3*ΔK+ (mmol l−1)A−0.1±0.1−0.2±0.0*−0.5±0.1*−0.2±0.1−0.1±0.1*B−0.2±0.1*−0.5±0.1*−0.3±0.1*−0.3±0.1*−0.1±0.1 * Significant within group; ^ significant between groups; P<0.05. All changes in group B had an earlier onset and were of the same or longer duration. Parameters not mentioned did not change clinically significant. FEV1‐ and dyspnoeic‐changes and FEV1 and FVC changes had a significant correlation in both groups. No other correlations or differences were seen. Group B shows no greater PF improvements, only significant and clinical relevant greater changes in some side effects. In moderate to severe COPD‐patients 5 mg albuterol is the highest recommended dose, lower doses should be investigated.