The effects of chlorpheniramine and antiallergic drugs on Ascaris suum antigen-induced active cutaneous anaphylaxis in dogs.

Effects of chlorpheniramine and two antiallergic drugs on the active cutaneous anaphylaxis (ACA) reaction induced by intradermal injection of Ascaris suum antigen in naturally sensitized dogs were investigated. Chlorpheniramine (10 mg/kg, intraduodenally (i.d.)) almost abolished the ACA reaction. NCO-650 (100 mg/kg, i.d.) had no inhibitory effect, while tranilast (300 mg/kg, i.d.) showed a weak inhibitory effect. These findings show that the ACA reaction is almost totally mediated by histamine and ACA reaction is considerably resistant to antiallergic drugs such as tranilast and NCO-650.