Effects of gender and race on albuterol pharmacokinetics

We evaluated the effects of race and gender on albuterol pharmacokinetics in 30 patients with moderate asthma (15 blacks, 15 whites, 16 men, 14 women). Subjects received a single dose of albuterol 8 mg oral solution and had blood samples collected at various times for 12 hours after the dose. Albuterol plasma concentrations were determined by HPLC with fluorescence detection, and pharmacokinetics were determined by compartmental analysis. The apparent volume of distribution of albuterol was significantly higher in men than in women (631+/-171 and 510+/-109 L, respectively, p<0.05). Consequently, the maximum concentration was lower in men than women (10.3+/-2.1 and 12.0+/-1.9 ng/ml, respectively, p<0.05). Elimination rates were 0.136+/-0.008 and 0.160+0.012 hour(-1), respectively (p<0.10). When corrected for ideal body weight, apparent volume of distribution was not different by gender. No differences between blacks and whites other than lag time were noted in albuterol kinetics. The greater apparent volume of distribution in men is likely explained by differences in ideal body weight or lean body mass.