Clinical efficacy of racemic albuterol versus levalbuterol for the treatment of acute pediatric asthma. Ann Emerg Med. Bob : If you have not seen a big marketing push from your local drug reps on levalbuterol Xopenex , you will very likely be targeted in the future more about that later. But is levalbuterol really better than the traditional beta agonist, albuterol Proventil , in children with acute exacerbations of asthma?
Bob : This study is a prospective randomized trial of children two to 14 years of age who presented to the emergency department with an acute exacerbation of asthma. One half of the children received nebulized albuterol, and the other half received levalbuterol. The doses chosen were weight based, and participants were eligible to receive up to five nebulization treatments.
What was the outcome? There was no difference between these agents in any effectiveness outcomes, including asthma scores, FEV 1 measures, number of nebulizations required, respiratory rates, pulse oximetry readings, length of emergency department care, or hospitalization rates Table 1. Levalbuterol has been promoted to have fewer side effects than albuterol. But were fewer side effects noted with this agent? Absolutely not Table 1. Bob : While there are a couple of minor limitations to this study, I believe it does get to the right answer.
Albuterol is composed of equal parts of a racemic mixture of R- and S-enantiomers; levalbuterol is composed of only the active R-enantiomer. Both agents contain an active ingredient, so there is no good reason why one should outperform the other. Some have postulated that the inactive S-enantiomer in albuterol may result in unwanted effects; however, this study debunks that theory. Andrea : One limitation of this study is that most of the participants had moderate asthma, raising the question about whether the results would be similar in children with severe asthma.
And because of the low hospitalization rate 13 percent , firm conclusions regarding this end point cannot be drawn.
Another limitation is the relatively small sample size, making it possible that, if there was a clinically meaningful difference, there were too few study participants for it to be statistically significant. But I agree with Bob; these are similar drugs and there is no reason why one would outperform the other. Many previous studies suggest that this is the case. Part of this spin is a result of which studies actually get published.
Companies are not knocking down doors to have negative studies published about their drugs. This is called publication bias.
Studies are more likely to get submitted for publication if they show a company's drug in a good light. However, if you look at all of the studies submitted to the FDA which I did , levalbuterol turns out to be no better than albuterol e. In fact, plain old albuterol had a superior side effect profile in a number of the studies. This trend of developing drugs that are simply an isomer of an existing drug is likely to boom as manufacturers attempt to replace drugs with expiring patents; it's all about market share.
Just look at esomeprazole Nexium and omeprazole Prilosec. Bob : With regard to market share, the makers of Xopenex Sepracor Inc. Currently, most of the 52 million annual prescriptions for albuterol are for metered-dose inhalers that contain chlorofluorocarbon CFC propellants. Because of the detrimental effects that CFC has on ozone levels, metered-dose inhalers containing CFC will be not be sold in the United States after Mark : Samples are given to physicians for one reason—marketing.
It has been clearly shown that samples will lead physicians to dispense and later prescribe brand name medications, even if these drugs were not the physician's preferred first-line choice. Andrea : If samples were not good business for the drug companies, the sample cabinet would be empty.
Azithromycin, a very common antibiotic often used in upper respiratory infections, should be avoided in combination with either levalbuterol or albuterol when possible.
Azithromycin, when administered with short-acting beta-agonists, has an increased risk of causing QT prolongation, a type of cardiac arrhythmia. It is important to obtain a baseline of cardiac function prior to administering these drugs at the same time. Beta blockers, often used to control heart rate and blood pressure, are functionally opposite of beta-agonists. Their functions will counteract each other.
If a patient must be both a beta blocker and a beta-agonist, using a cardioselective beta blocker is preferred. Examples of cardioselective beta blockers include atenolol and metoprolol, among others.
This is not a complete list of potential drug interactions. Please seek the medical advice of a healthcare professional for a complete understanding of potential drug interactions. If this occurs, therapy should be stopped immediately and a new treatment should be started.
Destabilization of asthma may occur over a period of hours, days, or longer. If an asthmatic patient begins to require an increasing amount of a bronchodilator to control asthma symptoms, this could be a sign that destabilization is occurring. Patients experiencing this may need anti-inflammatory treatments such as corticosteroids or a change in their maintenance medication regimen.
Levalbuterol and albuterol, especially at doses above the recommended amount, may cause serious cardiovascular effects such as increased heart rate and blood pressure.
In some serious cases, cardiac arrest has occurred. Never exceed the recommended dosing your doctor has prescribed. Low serum potassium levels, or hypokalemia, has been observed with levalbuterol and albuterol. This may be caused by intracellular shunting. While these drugs are sometimes used off-label to lower potassium levels intentionally, this effect should be monitored. Levalbuterol is a prescription drug that is a short-acting beta-agonist, also known as a bronchodilator.
It is used to treat bronchospasm related to asthma and COPD. It is also used off-label to help prevent exercise-induced bronchospasm. It is available in the form of a metered-dose inhaler as well as solutions to be used in a nebulizer. Albuterol is also a prescription drug that is a short-acting beta-agonist. It is also known as a bronchodilator and is used to treat bronchospasm related to asthma and COPD as well as to prevent exercise-induced bronchospasm.
It is available in various forms including oral tablets, oral solutions, metered-dose inhalers, and solutions to be used in a nebulizer.
Levalbuterol and albuterol are chemically similar, but they are not exactly the same. Albuterol is a racemic mixture of two chemical enantiomers, R-albuterol and S-albuterol. It is sometimes referred to as racemic albuterol. Levalbuterol is composed of just R-albuterol, the more active of the two compounds. Retrospective comparison studies overall have shown that levalbuterol and albuterol have similar clinical outcomes.
Prescribers may consider characteristics such a cost and potential adverse effects when selecting one over the other. Levalbuterol and albuterol are both considered pregnancy category C by the FDA. This means there are no good clinical studies to show safety in pregnancy. These drugs should only be used when the benefits clearly outweigh the risks. In these cases, albuterol may be preferred due to the presence of more historical data on its use in pregnancy. Many studies reporting greater efficacy or therapeutic index with levalbuterol treatment over albuterol are of questionable quality funded by the pharmaceutical company.
The claim that levalbuterol has a relatively lower cardioaccelerating effect compared to albuterol does not appear to be clinically supported in studies of the general population or in patients with baseline tachycardia. Furthermore, despite preclinical studies suggesting a theoretical clinical benefit, any therapeutic advantage of levalbuterol over albuterol on pulmonary function is still debated and requires further research. So before you write that nonformulary Xopenex order for your tachycardic asthma patient, think again.
Clin Rev Allergy Immunol. Levalbuterol Versus Albuterol. Current Allergy and Asthma Reports ; Single-isomer beta-agonist.
Pharmacotherapy ;21 3 pt. Preferential pulmonary retention of S -albuterol after inhalation of racemic albuterol. Am J respir Crit Care Med. Pharmacokinetic and pharmacodynamic characteristics and safety of inhaled albuterol enantiomers in healthy volunteers. J Clin Pharmacol. The asthma-like pharmacology and toxicology of S -isomers of beta agonists. J Allergy Clin Immunol. Adverse effects of beta-agonists. Improved bronchodilation with levalbuterol compared with racemic albuterol in patients with asthma.
J Allergy Clin Immunol ; The safety and efficacy of nebulized levalbuterol compared with racemic albuterol and placebo in the treatment of asthma in pediatric patients. The therapeutic ratio of R-albuterol is comparable with that of RS-albuterol in asthmatic patients.
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