Background: Various anesthetic drugs have been known to induce allergic reactions, which have been caused by histamine release from mast cells/basophils. Although lidocaine is reported to suppress allergic reactions, there have been no reports about lidocaine's direct effects to inhibit histamine release from mast cells/basophils.
Methods: We examined the effect of lidocaine on histamine release in vitro from freshly extracted as well as cultured mast cells and basophils. Additionally, the effects of lidocaine on intracellular calcium concentration were monitored by assessing Fura-2 signals in cultured cells.
Results: Lidocaine (10(-3)-10(-2) M: approximately 234-2340 micrograms/ ml) inhibited both the IgE-dependent and IgE-independent histamine release from all mast cells/basophils in a dose-dependent manner. However, lidocaine inhibited the IgE-dependent response more than the IgE-independent response (P < 0.01). Lidocaine also inhibited increases in intracellular Ca2+ to a greater extent after IgE-dependent stimulation as compared with IgE-independent stimulation. The degree of the inhibition of histamine release by lidocaine appeared to parallel decreases in Ca2+ mobilization.
Conclusions: Our results indicate that lidocaine directly inhibits histamine release from both rodent mast cells and human basophils in vitro at concentrations from 10(-3) to 10(-2) M (234 to 2340 micrograms/ml). That may be influenced by Ca2+ mobilization. Although these results are not immediately relevant to clinical practice, allergic reaction caused by direct effect of lidocaine seems to be impossible.