Is levalbuterol (Xopenex) more effective than albuterol?

The choice between levalbuterol and albuterol continues to be an area of contention for outpatients, in the emergency department, and those admitted into the hospital. Here is a brief explanation of the difference between the two products.

Albuterol is produced as a racemic mixture, meaning it contains both the (R)- and (S)-enantiomers of albuterol (this means that there is a chiral carbon in the drug that can have bonds arranged in one of two different ways – so both the (R)- and the (S)-albuterol have the same number of Cs, Hs, Os, etc, but have a different shape). Due to the difference in shape, the (R)-albuterol retains more therapeutic activity than the (S)-albuterol. In vitro studies have actually suggested that the (S)-albuterol may have deleterious effects on airway smooth muscle responsiveness. This led to the design and FDA approval of (R)-albuterol (levalbuterol) as its own product (1). Some studies have shown higher efficacy with levalbuterol versus albuterol while others do not. One study of children in the emergency department found that there were less hospital admissions when using levalbuterol but no difference in length of stay after the child was admitted (2). Critiques of the admission criteria used in this study have been made. The study showed no difference in adverse events including mean heart rate, mean maximal heart rate following a dose, respiratory rate, or oxygen saturation. Again, several other studies failed to show enhanced efficacy with levalbuterol (3-5).

There is a price difference to these products that has potentially serious financial consequences for patients and for the hospital budget. Cost for consumers at this time are about $1-2 for each dose of nebulized albuterol versus $6-7 for each dose of nebulized levalbuterol (6,7).

Take-home points: 

• There is a significant cost advantage to albuterol for the patient and the hospital 
• Levalbuterol is not universally accepted as a more effective or safer choice than albuterol
• Prescription insurance coverage may not initially cover levalbuterol for the above reasons

References:
1. Expert Report Panel 3: Guidelines for the Diagnosis and Management of Asthma. Available at: http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm. Accessed January, 2014.
2. Carl JC, Myers TR, Kirchner L, et al. Comparison of racemic albuterol and levalbuterol for treatment of acute asthma. J Pediatr 2003;143:731-6.
3. Cockcroft DW, Swystun VA. Effect of single doses of S-salbutamol, R-salbutamol, racemic
salbutamol, and placebo on the airway response to methacholine. Thorax
1997;52(10):845–8. 4. Lotvall J, Palmqvist M, Arvidsson P, Maloney A, Ventresca GP, Ward J. The therapeutic ratio of
R-albuterol is comparable with that of RS-albuterol in asthmatic patients. J Allergy Clin
Immunol 2001;108(5):726–31.
5. Qureshi F, Zaritsky A, Welch C, Meadows T, Burke BL. Clinical efficacy of racemic albuterol
versus levalbuterol for the treatment of acute pediatric asthma. Ann Emerg Med
2005;46(1):29–36.
6. Levalbuterol prescribing information. LexiComp. Available at: online.lexi.com Accessed January, 2014.
7. Albuterol prescribing information. LexiComp. Available at: online.lexi.com Accessed January, 2014.