Astemizole

Astemizole is a potent antihistamine (H1-receptor antagonist; IC₅₀ = 4 nM) that displays selectivity over dopamine, 5-HT, and muscarinic acetylcholine receptors. This compound has shown potent hERG K⁺ channel blocking activity (IC₅₀ = 0.9 nM), antimalarial activity in multidrug resistant strains in vitro (IC₅₀ = 227 - 734 nM), and has been used as a chaperone to correct folding defects and restore protein function for some mutated forms of hERG channels.