Alcaftadine, a imidazobenzazepine-based antagonist of the histamine receptors, has a pKi of 8.5 and 5.8 for the H1 receptor and H4 receptors, respectively. Additionally, Alcaftadine shows higher affinity for the H2 receptor than ketotifen. [1]

In support of its potent anti-inflammatory properties, Alcaftadine also exhibits modulatory action on immune cell recruitment and mast cell stabilizing effects. [2] Receptor binding studies revealed less significant effects ranging from a moderate affinity for cholinergic muscarinic receptors and lower affinity for human a2A-adrenoreceptors, serotonin 5-H51A, 5-HT2A receptors, and melanocortin MC4 receptors. [2] Furthermore, displacement experiments showed that at concentrations up to 10 uM, Alcaftadine did not interact with other receptors, transporters, or ion channel binding sites, including the hERG channel. [3]