Antibiotic concentrations in maxillary sinus secretions and in the sinus mucosa

In maxillary sinusitis, the blood circulation is supposed to be impaired in the oedematous sinus mucosa, and in such cases the transport of antibiotics into the maxillary sinus should be reduced. To prove the accuracy of this assumption a comparison has been made between the concentrations of penicillin and doxycycline (Vibramycin, Pfizer) in sinus mucosa and secretions and the serum concentrations in patients under treatment with these antibiotics. Measureable concentrations of penicillin (greater than 0.2 mug/ml) were reached in the secretions only if the serum concentration was high (greater than 4-5 mug/ml). In contrast, measurable concentrations of doxycycline were achieved in both mucosa and secretions in all patients treated with this antibiotic. This must depend on the fact that doxycycline, due to its optimal lipid solubility, was able to penetrate poorly vascularized tissue. In most cases, the concentrations of doxycycline far exceeded the minimum inhibitory concentrations of the isolated organisms, and in some cases the local concentrations were higher than those found in the serum. The clinical response to doxycycline was good and correlated well to the laboratory data.