Chlorpheniramine-d₆is intended for use as an internal standard for the quantification of chlorpheniramine by GC- or LC-MS. Chlorpheniramine is a histamine H₁receptor antagonist with an IC₇₅value of 0.0016 μg/ml for reversal of histamine-induced spasms in isolated guinea pig ileum.¹It protects against intravenous histamine-induced death (PD₅₀= 0.15 mg/kg) and delays induction of aerosolized histamine-induced coughing (ED_100sec= 0.44 mg/kg) in guinea pigs. Chlorpheniramine (20 mg/kg, i.p.) prevents histamine-induced passive cutaneous anaphylaxis (PCA) in rabbits.²It also reduces respiratory resistance and hypersecretion of tracheobronchial fluid in a dog model of histamine-induced asthma.³Formulations containing chlorpheniramine have been used in the treatment of seasonal allergies.

1.Lish, P.M., Robbins, S.I., and Peters, E.L.Specificity of antihistamine drugs and involvement of the adrenergic system in histamine deaths in the guinea pigJ. Pharmacol. Exp. Ther.153(3)538-543(1966) 2.Henson, P.M., and Cochrane, C.G.Immunological induction of increased vascular permeability. I. A rabbit passive cutaneous anaphylactic reaction requiring complement, platelets, and neutrophilsJ. Exp. Med.129(1)153-165(1969) 3.Yamatake, Y., Sasagawa, S., Yanaura, S., et al.Involvement of histamine H1- and H2-receptors in induced asthmas in dogsJpn. J. Pharmacol.27(6)791-797(1977)