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Levosalbutamol: Wikis

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Levosalbutamol
Systematic (IUPAC) name
4-[(1R)-2-(tert-butylamino)-1-hydroxyethyl]- 2-(hydroxymethyl)phenoll
Identifiers
CAS number 18559-94-9
ATC code R03AC02 R03CC02
PubChem 123600
DrugBank APRD00553
Chemical data
Formula C 13H21NO3  
Mol. mass 239.311 g/mol
SMILES eMolecules & PubChem
Pharmacokinetic data
Bioavailability  ?
Metabolism Hepatic
Half life 1.6 hours
Excretion Urinary
Therapeutic considerations
Pregnancy cat. A(AU) C(US)
Legal status -only (US)
Routes Oral, inhalational, IV
 Yes check.svgY(what is this?)  (verify)

Levosalbutamol (INN) or levalbuterol (USAN), trade name Xopenex, is the R-enantiomer of the short-acting β2-adrenergic receptor agonist albuterol (salbutamol). It is marketed by Cipla as Levolin.

Contents

Uses

As a bronchodilator, it is used to treat asthma and COPD. In general, levalbuterol has similar pharmacokinetic and pharmacodynamic properties 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.

Levosalbutamol vs. salbutamol

The use of levosalbutamol (levalbuterol) over the more traditionally used racemic salbutamol (albuterol) is controversial among health care professionals. That using levosalbutamol instead of salbutamol produces less direct effect on β1-adrenergic receptors and/or fewer cardiac side effects has been suggested, but not consistently demonstrated 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]

Approval

Levalbuterol was originally available only as a solution for nebulizer and eventually become available as a CFC-free metered dose inhaler under the trade name "Xopenex HFA (levalbuterol tartrate) Inhalation Aerosol". The FDA approval date was on March 11, 2005. (See Official FAQ)

Additional studies

In a study of cultured Human Airway Smooth Muscle Cells (HASMC) conducted by Bill T. Ameredes, PhD, and colleagues from the University of Pittsburgh, they concluded that the (S)-isomer found in racemic albuterol had a significant inhibitory effect on the presumed anti-inflammatory effect of dexamethasone, as inferred by increased release of GM-CSF. No P-value however was less than 0.05. The (R)- albuterol isomer was shown to enhance dexamethasone suppression of GM-CSF release. [4]

Dr. Ameredes has also proposed that the combination (R)(S)-Albuterol may be problematic. In his Conflict of Interest statement, Dr. Ameredes reports consultancy fees ($8500), advisory fees ($4500) and speaking fees ($7500) from Sepracor, Inc. [5]

References

  1. ^ [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi? cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16291438&query_hl=21&itool=pubmed_docsum Comparison of racemic albuterol and levalbuterol in the treatment of acute asthma in the ED.]
  2. ^ Levalbuterol is not more cost-effective than albuterol for COPD.
  3. ^ Point-Counterpoint: A Comparison of Levalbuterol and Racemic Albuterol in the Treatment of Pediatric Asthma.
  4. ^ Ameredes BT, Calhoun WJ (2005). "Modulation of GM-CSF release by enantiomers of beta-agonists in human airway smooth muscle". J. Allergy Clin. Immunol. 116 (1): 65–72. doi:10.1016/j.jaci.2005.03.007. PMID 15990776.  
  5. ^ Ameredes BT, Calhoun WJ (2006). "(R)-albuterol for asthma: pro [a.k.a. (S)-albuterol for asthma: con]". Am. J. Respir. Crit. Care Med. 174 (9): 965–9; discussion 972–4. doi:10.1164/rccm.2606001. PMID 17060667.  


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