Chlorpheniramine maleate is a small molecule H1-receptor antagonist. Increased ornithine decarboxylase activity induced in an is chemia-reperfusion state was attenuated by Chlorpheniramine Maleate, indicating that this increase is mediated through engagement of the H1-receptor by histamine. Histamine-mediated repair of intestinal mucosa following ischemia-reperfusion was also demonstrated to operate through the H1-receptor with Chlorpheniramine Maleate.

Induction of ornithine decarboxylase was blocked by Chlorpheniramine Maleate in Ehrlich carcinoma and MCF-7 cells. The positive inotropic effect of H1-receptor stimulation by histamine on protein tyrosine phosphorylation in guinea pig left atrium was antagonized by Chlorpheniramine Maleate.