Article: Levalbuterol

Xopenex®-HFA inhaler.

Levalbuterol (Xopenex®) is the R-enantiomer of the short-acting β₂-adrenergic receptor agonist albuterol. As a bronchodilator, it is used to treat asthma and COPD. In general, levalbuterol has similar effects, pharmacokinetics, and pharmacodynamics to albuterol. However, its manufacturer, Sepracor, has implied (although not directly claimed) that the presence of only the R-enantiomer produces fewer side-effects. Physicians sometimes elect to use levalbuterol in patients with a history of supraventricular tachycardia or other arrhythmias because it is thought that levalbuterol may produce less direct effects on β1 adrenergic receptors in the heart. For similar reasons some pediatricians also use levalbuterol for patients who experience hyperactivity or jitteriness from racemic albuterol.

The use of levalbuterol over the more traditionally used racemic albuterol is controversial among health care professionals. That using levalbuterol instead of albuterol produces less direct effect on β1 adrenergic receptors and/or less cardiac side effects has been suggested, but not consistently proven by long term, well designed clinical trials. There are differing opinions on whether there is sufficient therapeutic benefit to using levalbuterol that outweighs the 5-10 times higher price tag. ^[1][2] In general, it appears that if a clinician and patient feel that a low dose of racemic mixture is causing undesirable side effects, levalbuterol may be a viable alternative.^[3]

Levalbuterol was originally available only as a solution for nebulizer but has recently (as of late 2005) become available as a CFC-free metered-dose inhaler (Xopenex®-HFA).