Histamine H1 receptor

Bepotastine possesses additional anti-allergic activity including stabilization of mast cell function, inhibition of eosinophilic infiltration, inhibition of IL-5 production, and inhibition of leukotriene B4 (LTB4) and LTD4 activity.
Bepotastine significantly inhibits antigen-induced stimulation of IL-5 production in human peripheral blood mononuclear cells (PBMCs) at concentrations of 10-100 μM and the effect is enhanced when the PBMCs are pre-incubated with Bepotastine.
Leukotriene B4 increased Ca2+ concentration in cultured neutrophils, which is suppressed by Bepotastine besilate (1-100 μM). Leukotriene B4 increased Ca2+ concentration in cultured dorsal root ganglion neurons, which is also suppressed by Bepotastine besilate (100 μM).

Bepotastine besilate (10 mg/kg) inhibits scratching induced by an intradermal injection of histamine (100 nmol/site), but not serotonin (100 nmol/site).
Bepotastine besilate (1-10 mg/kg, oral) dose-dependently suppresses scratching induced by substance P (100 nmol/site) and leukotriene B4 (0.03 nmol/site). Bepotastine in vivo dose-dependently inhibits the acceleration of histamine-induced vascular permeability and inhibits homologous passive cutaneous anaphylaxis in guinea pig studies.
In mouse models of itching, oral Bepotastine inhibits the frequency and duration of scratching behavior.