Azithromycin concentrations in sinus fluid and mucosa after oral administration

The concentrations of azithromycin in sinus fluid and mucosal tissue were determined in a total of 23 patients with acute or chronic sinusitis. Five patients with acute sinusitis and four with chronic sinusitis were administered a five-day course of oral azithromycin (500 mg on day 1, 250 mg on days 2-5, all as single doses), and the remaining 14 patients, all with chronic sinusitis, received single oral doses of azithromycin (500 mg). With the five-day regimen, the mean levels of azithromycin in sinus fluid were markedly higher in patients with acute sinusitis (1.34 micrograms/ml) than in patients with chronic sinusitis (0.25 micrograms/ml) 24 h after the first dose. The levels of azithromycin in the sinus fluid increased from the first to the last dose in both patient groups; the mean levels of azithromycin 24 h after the last dose were 2.33 micrograms/ml in acute sinusitis patients and 0.38 micrograms/ml in chronic sinusitis patients. In chronic sufferers, the mean levels of azithromycin in the sinus fluid following a single oral dose were 0.25, 0.41, 0.57 and 0.22 micrograms/ml at 24, 48, 72 and 96 h, respectively, after administration. In these patients the mean sinus drug concentrations were much greater in the mucosal tissue (1.23 micrograms/g) than in the sinus fluid (0.41 micrograms/ml) 48 h after administration of the single dose. There were no treatment-related changes in laboratory function tests, and side effects were described as mild to moderate (five patients complained of nausea, abdominal pain or headache).(ABSTRACT TRUNCATED AT 250 WORDS)