Pharmacokinetics of salicylates administered with metoprolol

The widely used acetylsalicylic acid (ASA, Colfarit) was administered in combination with metoprolol (Lopresor) during 7 days. Plasma concentrations of total salicylates (ASA and salicylic acid (SA) and metoprolol were monitored during the treatment period, on day 7 urinary excretion was also investigated. The kinetic data of the compounds were compared to those of the metoprolol and ASA control periods. Metoprolol kinetics remained uninfluenced whereas the maximal plasma concentrations of the salicylates were significantly higher than in the ASA control period.