Potent and highly selective histamine H3 receptor antagonist (pA2 = 8.4); displays > 30000-fold selectivity over H1 and H2 receptors. Can act as a partial agonist in SK-N-MC cells expressing human H3 receptors. Produces antinociception, possibly via a non-H1, -H2 or -H3 receptor-mediated mechanism, following central administration in vivo.