Dexchlorpheniramine is a histamine H1 receptor antagonist with a pA2 value of 9.36 in guinea pig ileal tissue in vitro. [1] It inhibits the proliferation of previously sensitized, allergen-challenged peripheral blood mononuclear cells by 92% at a concentration of 4.8 &#181M. [2] Dexchlorpheniramine reduces noradrenaline uptake in the rat vas deferens ex vivo in response to tyramine stimulation when used at a concentration of 10 &#181M.[3] In vivo, dexchlorpheniramine increases the pain threshold of mice exposed to thermal and chemical stimulation tests when administered intraperitoneally at a dose of 30 mg/kg.[4] Formulations containing dexchlorpheniramine have been used for the treatment of allergic reactions.

Reference:
[1]. Shamsa, F., Ahmadiani, A., and Khosrokhavar, R. Antihistaminic and anticholinergic activity of barberry fruit (Berberis vulgaris) in the guinea-pig ileum. J. Ethnopharmacol. 64(2), 161-166 (1999).
[2]. Holen, E., Elsayed, S., and Nyfors, A. The effect of H1 receptor antagonists on peripheral blood mononuclear cells, adenoid cells and primary cell lines. APMIS 103(2), 98-106 (1995).
[3]. Barnett, A., Symchowicz, S., and Taber, R.I. The effects of drugs inhibiting catecholamine uptake on tyramine and noradrenaline-induced contractions of the isolated rat vas deferens. Br. J. Pharmacol. 34(3), 484-492 (1968).
[4]. Farzin, D., Asghari, L., and Nowrouzi, M. Rodent antinociception following acute treatment with different histamine receptor agonists and antagonists. Pharmacol. Biochem. Behav. 72(3), 751-760 (2002).