Arformoterol is the R,R enantiomer of formoterol. Arformoterol exhibits anti-inflammatory and anti-asthma activities, potentiating the effects of co-administered glucocorticoids in the treatment of asthma and chronic obstructive pulmonary disorder (COPD). Arformoterol activates β2-adrenergic receptors and bitter taste receptors (TAS2Rs) in bronchi, inducing airway relaxation through β2 adrenergic receptor downstream signaling effects on intracellular cAMP and Ca2+ levels. Additionally, arformoterol’s activation of TAS2Rs is thought to involve inhibition of PI3K signaling. Arformoterol inhibits migration of human airway smooth muscle cells through other β2 adrenergic receptor downstream signaling effects on PKA and vasodilator-stimulated phosphoprotein (VASP). In vitro, arformoterol inhibits phosphorylation of JNK, p38 MAPK, and the glucocorticoid receptor.