Is the administration of doxycycline still indicated in bacterial infections of the gallbladder and the bile ducts?

The levels of doxycycline in serum, bile and the gallbladder wall were determined in 25 patients during cholecystectomy, by means of bioassay after previous intravenous administration of doxycycline. The mean biliary level exceeded 20 microgram/ml, and the mean level in the gallbladder wall was greater than 2 microgram/g. With few exceptions all the levels found clearly exceeded the MIC of most relevant pathogens. This was confirmed by the levels found in bile drained via T-Tube. Thus, clinically important breakdown of doxycycline by the mainly alkaline bile acids should not be anticipated.