Pharmacology Update
Levalbuterol Tartrate Inhalation Aerosol (Xopenex HFA™)
By William T. Elliott, MD, FACP, and James Chan, PhD, PharmD Dr. Elliott is Chair, Formulary Committee, Northern California Kaiser Permanente; Assistant Clinical Professor of Medicine, University of California, San Francisco; Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland, CA. Drs. Chan and Elliott report no financial relationships to this field of study.
The FDA has approved a cfc-free levalbuterol aerosol inhaler for the treatment of asthma. Levalbuterol is the active isomer of albuterol and has been available in a nebulized solution for many years. This new formulation is marketed by Sepracor as Xopenex HFA™.
Indications
Levalbuterol inhalation aerosol is indicated for the treatment or prevention of bronchospasm in adults, adolescents, and children 4 years of age or older with reversible obstructive airway disease.1
Dosage
The recommended dose is 2 inhalations every 4 to 6 hours. In some patients 1 inhalation every 4 hours may be adequate.1
Levalbuterol is available as a 15-gram canister containing 200-metered actuations. Each actuation delivers 45 mg of levalbuterol base.
Potential Advantages
The inhalation aerosol provides levalbuterol with a more widely used dosage form.
Potential Disadvantages
In comparative trials a higher frequency of dizziness, pharyngitis, rhinitis, have been reported with levalbuterol HFA compared to albuterol HFA.1
Comments
Levalbuterol HFA provides a more convenient and more widely used form of an inhaled beta agonist. Albuterol is the most commonly used beta2 agonist and it is a racemic mixture of (R) and (S) enantiomers. The (R)-enantiomer is about 100-fold more potent than the (S)-enantiomer. In comparative studies, levalbuterol HFA and racemic albuterol HFA appear to show similar improvement in FEV1 compared to placebo.1 These data were from two 8-week randomized, double-blind, active- and placebo- controlled studies in 748 adults and adolescents and a 4-week study in pediatric patients.1 The pharmacodynamic effect of the (S)-enantiomer is somewhat unclear. Some data suggest that this enantiomer may antagonize the effects of the active enantiomer with pro-bronchoconstriction and pro-inflammatory action.3 The nebulized form of levalbuterol has shown favorable outcomes compared with racemic albuterol generally in acute and severe asthma.4-6 Outcomes included reduced number of hospitalizations and greater improvement in pulmonary function. Comparable bronchodilation effect has been shown with levalbuterol 0.63 mg and 2.5 mg of albuterol.6,7 Comparative clinical trials between the levalbuterol HFA and albuterol inhaler have not been published. Data from the product information suggest similar effect on pulmonary function.1 The wholesale cost for Xopenex HFA™ is $39.80 compared to $35.07 for Proventil® HFA.
Clinical Implications
Levalbuterol HFA provides another option for a short acting beta2 agonist. It's not known if this formulation provides any clear clinical advantages over the racemic inhaler.
References
1. Xopenex HFA Product Information. Sepracor Inc, September 2005.
2. Penn RB, et al. Comparison of R-, S-, and RS-albuterol interaction with human beta 1- and beta 2-adrenergic receptors. Clin Rev Allergy Immunol. 1996;14:37-45.
3. Agrawal DK, et al. (S)-Albuterol activates pro-constrictory and pro-inflammatory pathways in human bronchial smooth muscle cells. J Allergy Clin Immunol. 2004;113:503-510.
4. Carl JC, et al. Comparison of racemic albuterol and levalbuterol for treatment of acute asthma. J Pediatr. 2003;143:731-736.
5. Gawchik SM, et al. The safety and efficacy of nebulized levalbuterol compared with racemic albuterol and placebo in the treatment of asthma in pediatric patients. J Allergy Clin Immunol. 1999;103:615-621.
6. Nelson HS, et al. Improved bronchodilation with levalbuterol compared with racemic albuterol in patients with asthma. J Allergy Clin Immunol. 1998; 102(6 Pt 1):943-952.
7. Handley DA, et al. Dose-response evaluation of levalbuterol versus racemic albuterol in patients with asthma. J Asthma. 2000;37:319-327.
The FDA has approved a cfc-free levalbuterol aerosol inhaler for the treatment of asthma. Levalbuterol is the active isomer of albuterol and has been available in a nebulized solution for many years. This new formulation is marketed by Sepracor as Xopenex HFA.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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