Ampicillin concentrations in middle ear effusions in acute otitis media after administration of bacampicillin.

The penetration of ampicillin into middle ear effusions after oral administration of 800 mg bacampicillin to patients with acute otitis media was studied and compared with the serum levels. One hour after administration a mean (+/- SEM) concentration of 2.4 +/- 0.4 micrograms/ml ampicillin was found in the effusions and the mean serum level was 7.7 +/- 0.8 micrograms/ml. After twelve hours a mean concentration of 0.6 +/- 0.2 micrograms/ml was found in the middle ear effusions and 0.1 +/- 0.03 micrograms/ml in the serum. The high concentration of ampicillin in middle ear effusions after twelve hours suggests that a twice daily dosage of bacampicillin should be given in acute otitis media.