Abstract
Low-dose long-term treatment of 14-membered ring macrolide antibiotics has been reported to be effective in the treatment of various chronic respiratory diseases, including chronic sinusitis (low-dose macrolide therapy). Clarithromycin (CAM) is the most commonly used drug for low-dose macrolide therapy, however only few data about the tissue distribution of the drug in patients are available. To evaluate the tissue distribution of CAM, the serum and tissue concentrations of the drug were measured in 5 chronic sinusitis patients during macrolide therapy (200 mg/day for 14 days or more). Three hrs after oral administration of CAM (200 mg), nasal polyp and serum specimens were obtained from the patients at the time of endoscopic sinus surgery. The serum and nasal polyp concentrations of both CAM and 14-hydroxyclarithromycin (14-OH CAM ; hydroxylation at 14-position), which is an active metabolite, were measured. The concentrations in the nasal polyps (median, n=5) were 7.00 μg/ml for CAM and 1.36 μg/ml for 14-OH CAM, which were 12.3 times and 9.9 times the serum concentrations, respectively. These results confirmed that the concentrations of CAM are high in nasal polyps, consistent with the high clinical efficacy of the drug.
