The effect of an oral therapeutic single dose of doxycycline on subsequent monocyte phagocytosis in vitro.

Doxycycline has been reported to depress leukocyte functions. The effect of peroral administration of 400 mg doxycycline was evaluated after 24 hours in 18 healthy persons. No inhibitory effect on monocyte phagocytosis was found. There is no evidence that therapeutic concentrations of doxycycline depress leukocyte functions to a degree of clinical significance.