Levalbuterol hydrochloride. Molecular model of the drug levalbuterol hydrochloride (C13.H21.N.O3?H.Cl). This short-acting beta2 adrenergic receptor agonist is, sold under the brand name Xopenex. It is used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue), oxygen (red) and chlorine (green).