Oral absorption of clarithromycin in acute illness and during convalescence in patients with community-acquired pneumonia

Study objective: To compare the extent of oral clarithromycin absorption in patients during an illness and in health. Design: Sequential two-phase prospective study including an acutely ill pne umonia phase (PP) and a subsequent convalescent phase (CP). Study population: Patients greater than or equal to 18 years old with radio graphically confirmed community-acquired pneumonia (CAP) who were admitted to the hospital. Methods: During both study phases, patients received one single 500-mg dose of oral clarithromycin. Serial blood samples were drawn over a 24-h period in order to characterize the plasma concentration-time curves. Area under the curve from zero to 24 h (AUC(0-24)), maximum plasma concentration (Cmax ), and time to maximum concentration (Tmax) were determined for both clarit hromycin and its metabolite, 14-hydroxyclarithromycin, and compared between the two phases. Results: Twelve patients completed both phases of the stud y. For clarithromycin, there was a significant increase AUC(0-24) (47.37 +/ - 8.51 mu g/h/mL vs 36.22 +/- 6.09 mu g/h/mL) in favor of the PP. There wer e no significant differences detected with respect to Cmax (4.32 +/- 0.63 m u g/mL vs 3.57 +/- 0.46 mu g/mL), or Tmax (3.50 +/- 0.50 h vs 2.83 +/- 0.59 h) between PP and CP. For 14-hydroxyclarithromycin , the AUC(0-24) and Cma x were significantly higher (5.84 +/- 1.08 mu g/h/mL vs 8.84 +/- 1.92 mu g/ h/mL; 0.42 +/- 0.08 mu g/mL vs 0.76 +/- 0.23 mu g/mL) in the CP as compared to the PP. Tmax remained unchanged. Conclusion: The extent of absorption of oral clarithromycin was not diminis hed during an acute illness with CAP.