In vitro effects of clarithromycin on human polymorphonuclear leukocyte functions

Background: It has been shown that antibacterial agents affect polymorphonu clear leukocytes (PMNs), which are active in the body's first line of defen se, in different ways. However, few studies have investigated the effects o f tablet dosage forms as opposed to pure powder forms. There is a need to d emonstrate the clinical relevance of previous results with commercially ava ilable products. Methods: We examined the effects of clarithromycin solutio ns, prepared separately from either pure powder or commercially available t ablets (250 mg), on human PMNs. The in vitro effects of each solution, adju sted to therapeutic concentration (1 mg/l), on PMN adherence, chemotaxis, p hagocytosis, candidacidal capacity and superoxide production were studied. Results: Solutions prepared from pure clarithromycin powder did not affect the adherence, phagocytosis or superoxide production of PMNs, but did inhib it (p < 0.05) chemotaxis and candidacidal capacity. By contrast, a decrease (p < 0.05) in all functions except phagocytosis was observed with solution s prepared from the tablet dosage form of clarithromycin. Conclusion: The r esults of this study suggest that the tablet dosage form of clarithromycin may have a more pronounced inhibitory effect on human PMN functions than so lutions prepared from the pure powder form. Copyright (C) 2000 S. Karger AG , Basel.