Orally active, potent histamine H1 antagonist (IC50 = 4 nM) that displays 20-fold, > 250-fold and > 250-fold selectivity over 5-HT, dopamine and muscarinic acetylcholine receptors respectively. Exhibits antimalarial activity in multidrug resistant strains in vitro (IC50 = 227 - 734 nM). Also potent hERG K+ channel blocker (IC50 = 0.9 nM) that displays cardiotoxicity in vivo.