Levalbuterol has not been established to have therapeutic advantage over racemic albuterol

Salbutamol in the Management of Asthma: A Review

Asthma is a common inflammatory disease of the lungs. The prevalence of asthma is increasing worldwide, and the tendency indicates that the number of asthma sufferers will soar in the coming years for several reasons, in particular, the lifestyles we have adopted that expose us to risk factors. Salbutamol is the first selective short-acting β2-agonist (SABA) used as an alternative reliever in the treatment of asthma. Its therapeutic effect is based on its potent smooth muscle relaxant properties, which allow the inhibition of bronchial smooth muscle contraction and subsequent bronchodilation. Salbutamol can be administered orally, intravenously (IV), intramuscularly (IM), subcutaneously, or by inhalation. For this reason, the pharmacokinetic (PK) parameters-absorption, distribution, metabolism, and elimination-are highly diverse and, consequently, the efficacy and adverse effects also differ between each formulation. Here, we review the pharmacological profile of different salbutamol formulations, focusing on their efficacy and adverse effects for its original application, asthma.

Addition of levalbuterol to a pediatric emergency department automated medication management system does not increase its use

Background

Aims

Methods

Results

Conclusions

(R)-albuterol for asthma: pro [a.k.a. (S)-albuterol for asthma: con]

Is there scientific evidence to support the replacement of the beta-agonist racemic albuterol with levalbuterol--that is, (R)-albuterol? The argument presented further refines the question as "Do we wish to continue to treat asthma with a mixture of albuterol, of which half is an agent with no known benefit--that is, (S)-albuterol--and which may exacerbate the disease?"

Evaluation of levalbuterol metered dose inhaler in pediatric patients with asthma: a double-blind, randomized, placebo- and active-controlled trial

OBJECTIVE

To evaluate the efficacy and safety of levalbuterol metered dose inhaler (MDI) in children aged 4-11 years (n = 173).

RESEARCH DESIGN AND METHODS

Multicenter, randomized, double-blind 28-day study of QID levalbuterol 90 microg, racemic albuterol 180 mug, and placebo (2:1:1 ratio). Serial spirometry was performed on Days 0, 14, and 28. The primary endpoint was the double-blind average peak percent (%) change in FEV(1) from visit pre-dose; the primary comparison was with placebo. Secondary endpoints included the area under the FEV(1) percent change from pre-dose curve and peak % predicted FEV(1). Safety endpoints included adverse events, laboratory tests, rescue medication use, and electrocardiograms.

RESULTS

Levalbuterol significantly improved the least square mean peak percent change in FEV(1) compared with placebo (levalbuterol 25.6% +/- 1.3% [p < 0.001]; racemic albuterol 21.8% +/- 1.8% [p = ns]; placebo 16.8% +/- 1.9%). Results for levalbuterol were similar for the other spirometry endpoints (p < 0.05 vs. placebo). No levalbuterol-treated patients had a peak percent change in FEV(1) < 10% (compared with 15.8% of racemic albuterol-treated patients and 30.3% of placebo-treated patients). The incidence of adverse events was 43.4% for levalbuterol, 56.4% for racemic albuterol, and 51.4% for placebo. The rate of discontinuation was 1.3% for levalbuterol, 2.6% for racemic albuterol, and 8.6% for placebo. The rate of asthma attacks (10.5%, 12.8%, 14.3%, respectively) was similar among treatments. Levalbuterol and racemic albuterol both reduced rescue medication use (p < 0.01 vs. placebo) and produced changes in ventricular heart rate and QT(c-F) that were similar to placebo.

CONCLUSIONS

In this study, levalbuterol administered via MDI significantly improved airway function in comparison with placebo in asthmatic children aged 4-11 years with a safety profile that was similar to placebo.

Single-enantiomer drugs: elegant science, disappointing effects

Most new drugs are marketed as single enantiomers but many older agents are still available in racemic form. As these drugs reach the end of their patent life manufacturers become interested in marketing single enantiomer equivalents. This is called 'chiral switching' and it has been claimed that it will bring clinical benefits in terms of improved efficacy, more predictable pharmacokinetics or reduced toxicity. We reviewed the clinical evidence and prices for three recently marketed single enantiomer versions of widely used racemic drugs: escitalopram, esomeprazole and levosalbutamol. Claims of increased efficacy were based on comparisons of non-equivalent doses and any advantages seemed small and clinically unimportant. Prices of esomeprazole and levosalbutamol were higher than their racemic alternatives and we predict that these prices will remain high despite the market presence of generic versions of the racemates. Patent protection and a perception of superiority based on promotion rather than evidence will maintain price premiums for single enantiomer drugs that are not justified on the basis of clinical performance.

Levalbuterol: pharmacologic properties and use in the treatment of pediatric and adult asthma

LEARNING OBJECTIVES

To review the rationale supporting the use of levalbuterol [(R)-albuterol] for the treatment of pediatric and adult asthma.

DATA SOURCES

Peer-reviewed articles, selected abstracts from studies presented at recent professional meetings, and the Xopenex [levalbuterol, (R)-albuterol; Sepracor, Marlborough, MA] Summary Basis of Approval and package insert.

STUDY SELECTION

Institutional review board-approved clinical study protocols.

RESULTS

Levalbuterol is a single isomer beta2-agonist that differs from racemic albuterol by elimination of (S)-albuterol. Levalbuterol is an effective bronchodilator whose primary mechanism of action is unimpeded by (S)-albuterol. Thus, when compared with racemic albuterol, clinically comparable bronchodilation can be achieved with doses that substantially lessen beta-mediated side effects. In chronic or acute treatment of asthma, this favorable therapeutic profile cannot apparently be duplicated by increasing or decreasing the dose of racemic albuterol or by the addition of anticholinergic agents such as ipratropium bromide.

CONCLUSIONS

Levalbuterol seems to provide efficacy and safety advantages in pediatric and adult patients suffering from asthma. Its use may afford a cost benefit as well. More clinical studies are required to extend these observations for use in the treatment of other pulmonary diseases in both adults and children and to determine levalbuterol's impact on long-term therapy of respiratory diseases.

Single-isomer levalbuterol: a review of the acute data

Levalbuterol, the pure (R)-isomer of racemic albuterol, is a new therapeutic option for patients with asthma. Racemic albuterol comprises a 50:50 mixture of (R)- and (S)-albuterol, with (R)-albuterol conferring all of the bronchodilator effects of the racemate. Numerous preclinical and in vitro studies have indicated that (S)-albuterol is not an inert isomer, but may have proinflammatory effects. Results from clinical trials in adults and children with asthma have demonstrated that 0.63 mg levalbuterol provides effective bronchodilation with lower b-mediated side effects compared with 2.5 mg racemic albuterol. In the emergency department, levalbuterol provided greater bronchodilation and significantly reduced hospital admissions compared with racemic albuterol. Recent studies have supported that levalbuterol use in acute settings may reduce the cost of asthma treatment by decreasing the total treatments and subsequent respiratory therapy resources. Levalbuterol provides heath care professionals with a safe, effective, and potentially cost-saving alternative to racemic albuterol for the treatment of patients with asthma.

6. Asthma

The increasing incidence and prevalence of asthma in many parts of the world continue to make it a global health concern. The heterogeneous nature of the clinical manifestations and therapeutic responses of asthma in both adult and pediatric patients indicate that it may be more of a syndrome rather than a specific disease entity. Numerous triggering factors including viral infections, allergen and irritant exposure, and exercise, among others, complicate both the acute and chronic treatment of asthma. Therapeutic intervention has focused on the appreciation that airway obstruction in asthma is composed of both bronchial smooth muscle spasm and variable degrees of airway inflammation characterized by edema, mucus secretion, and the influx of a variety of inflammatory cells. The presence of only partial reversibility of airflow obstruction in some patients indicates that structural remodeling of the airways may also occur over time. Choosing appropriate medications depends on the disease severity (intermittent, mild persistent, moderate persistent, severe persistent), extent of reversibility, both acutely and chronically, patterns of disease activity (exacerbations related to viruses, allergens, exercise, etc), and the age of onset (infancy, childhood, adulthood).