[The bioavailability of combination preparations of acetylsalicylic acid and codeine phosphate]

Plasma levels time curves of acetylsalicylic acid, salicylic acid, salicyluric acid and codeine were monitored after intravenous, oral and rectal application (single dose) of preparations containing acetylsalicylic acid and codeine. The mean absolute bioavailability of acetylsalicylic acid was 68% after oral application and 60% after rectal application. The corresponding bioavailability data of codeine were 59% and 63%, respectively.