[Comparison of beta-blocking agents pharmacokinetics in obese and non-obese subjects]

We compared in obese patients and normal subjects, the pharmacokinetics of three drugs with different solubility: d,l-sotalol markedly hydrophilic, d,l-propranolol highly lipophilic, d,l-bisoprolol moderately lipophilic. In obese subjects the pharmacokinetic data calculated for sotalol (total clearance (CL), volume of distribution (V beta), half-life of elimination (t1/2), were comparable with those measured in the controls. Data on bisoprolol showed that total V beta increased with excess of body weight, but V beta/kg of body weight was lower in obese subjects than in the controls, CL tended to increase and t1/2 was similar. As concerned propranolol, total V beta and V beta/kg were significantly lower in obese than in control subjects. Cl was decreased in obese patients and t1/2 was similar for both groups. It appears that in the obese the diffusion of liposoluble beta-blockers in the fatty excess weight remains limited. It is possible that a vasoconstrictive effect induced by beta-blockers in adipose tissues could restrict their tissular distribution.