Alcaftadine (S4625-GRP)

Alcaftadine (Lastacaft, R89674) is a high affinity ligand for the H1 receptor, with a pKi (8.5) that is comparable with that of other H1 antihistamines. Alcaftadine is also an antagonist for H2 and H4 receptors with no affinity for the H3 receptor.