Chemistry:Levosalbutamol
Levosalbutamol, also known as levalbuterol, is a β2-adrenergic receptor agonist used in the treatment of bronchospasm.[1] Levosalbutamol is the (R)-(−)-enantiomer of its prototype drug salbutamol.[2]
Medical use
Levosalbutamol is indicated for the treatment or prevention of bronchospasm in people aged four years of age and older with reversible obstructive airway disease.[1]
Comparison to salbutamol
Evidence is inconclusive regarding the efficacy of levosalbutamol versus salbutamol (albuterol) or salbutamol-levosalbutamol combinations, though levosalbutamol is believed to have a better safety profile due to its more selective binding to β2 receptors (primarily in the lungs) versus β1 (primarily in heart muscle).[3][4]
A 2013 systematic review of the use of levalbuterol as a treatment for acute asthma found that it "was not superior to albuterol regarding efficacy and safety in subjects with acute asthma." The review concluded: "We suggest that levalbuterol should not be used over albuterol for acute asthma."[3]
Adverse effects
Generally, levosalbutamol is well tolerated. Common mild side effects include an elevated heart rate, muscle cramps, and gastric upset (including heartburn and diarrhea).[5]
Symptoms of overdose in particular include: collapse into a seizure; chest pain (possible precursor of a heart attack); fast, pounding heartbeat, which may cause raised blood pressure (hypertension); irregular heartbeat (cardiac arrhythmia), which may cause paradoxical lowered blood pressure (hypotension); nervousness and tremor; headache; dizziness and nausea/vomiting; weakness or exhaustion (medical fatigue); dry mouth; and insomnia.[5]
Rarer side effects may indicate a dangerous allergic reaction. These include: paradoxical bronchospasm (shortness of breath and difficulty breathing); skin itching, rash, or hives (urticaria); swelling (angioedema) of any part of the face or throat (which can lead to voice hoarseness), or swelling of the extremities.[5]
Pharmacology
Mechanism of action
Activation of β2 adrenergic receptors on airway smooth muscle leads to the activation of adenylate cyclase and to an increase in the intracellular concentration of 3',5'-cyclic adenosine monophosphate (cyclic AMP). The increase in cyclic AMP is associated with the activation of protein kinase A, which in turn, inhibits the phosphorylation of myosin and lowers intracellular ionic calcium concentrations, resulting in muscle relaxation.[6]
Levosalbutamol relaxes the smooth muscles of all airways, from the trachea to the terminal bronchioles. Increased cyclic AMP concentrations are also associated with the inhibition of the release of mediators from mast cells in the airways. Levosalbutamol acts as a functional agonist that relaxes the airway irrespective of the spasmogen involved, thereby protecting against all bronchoconstrictor challenges.
While it is recognized that β2 adrenergic receptors are the predominant receptors on bronchial smooth muscle, data indicate that there are beta receptors in the human heart, 10–50% of which are β2 adrenergic receptors. The precise function of these receptors has not been established. However, all β-adrenergic agonist drugs can produce a significant cardiovascular effect in some patients, as measured by pulse rate, blood pressure, and restlessness symptoms, and/or electrocardiographic (ECG).
Levosalbutamol and salbutamol do not racemize significantly before being eliminated from the human body.[7] Enantiomerically pure levosalbutamol is preferred over racemic salbutamol in most cases, because the other optical isomer (S-salbutamol) has some negative side-effects.[7]
Society and culture
Levosalbutamol is on the list of drugs banned by the World Anti-Doping Agency.[8]
Economics
Levalbuterol is more costly than salbutamol.[9][10]
Legal status
Levalbuterol was approved in the United States as a solution to be used with a nebulizer device in March 1999,[11] and in March 2005, became available in a formulation with a metered-dose inhaler under the brand name Xopenex HFA (levalbuterol tartrate inhalation aerosol).[12]
Names
Levosalbutamol is the international nonproprietary name and levalbuterol is the United States Adopted Name. It is available in Bangladesh as Purisal by Incepta Pharmaceuticals Ltd.
References
- ↑ 1.0 1.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedXopenex FDA label - ↑ "Levosalbutamol". BioDrugs 11 (6): 431–438. June 1999. doi:10.2165/00063030-199911060-00007. PMID 18031154.
- ↑ 3.0 3.1 "Levalbuterol versus albuterol for acute asthma: a systematic review and meta-analysis". Pulmonary Pharmacology & Therapeutics 26 (2): 239–248. April 2013. doi:10.1016/j.pupt.2012.11.003. PMID 23207739.
- ↑ "Levosalbutamol vs racemic salbutamol in the treatment of acute exacerbation of asthma". Indian Journal of Pediatrics 76 (11): 1131–1135. November 2009. doi:10.1007/s12098-009-0245-4. PMID 20012785.
- ↑ 5.0 5.1 5.2 "Levalbuterol Oral Inhalation". MedlinePlus. Bethesda, Maryland: U.S. National Library of Medicine, National Institutes of Health. 1 September 2010. https://www.medlineplus.gov/druginfo/meds/a603025.html.
- ↑ "Bronchodilator and Antihyperkalemic Effects of Salbutamol (Albuterol) in Neonates and Young Infants" (in en). Journal of Pediatric Biochemistry 05 (03): 082–087. 2016-02-09. doi:10.1055/s-0036-1571852. ISSN 1879-5390.
- ↑ 7.0 7.1 "Evidence based review on levosalbutamol". Indian Journal of Pediatrics 74 (2): 161–167. February 2007. doi:10.1007/s12098-007-0010-5. PMID 17337829.
- ↑ "The Prohibited List". 1 January 2025. https://www.wada-ama.org/en/prohibited-list.
- ↑ "Comparison of racemic albuterol and levalbuterol in the treatment of acute asthma in the ED". The American Journal of Emergency Medicine 23 (7): 842–847. November 2005. doi:10.1016/j.ajem.2005.04.003. PMID 16291438.
- ↑ "Levalbuterol is not more cost-effective than albuterol for COPD". Chest 124 (3): 1176; author reply 1176–1176; author reply 1178. September 2003. doi:10.1378/chest.124.3.1176. PMID 12970057.
- ↑ "Drug Approval Package: Xopenex (Levalbuterol HCI) NDA# 20-837". 20 June 2001. https://www.accessdata.fda.gov/drugsatfda_docs/nda/99/20837_Xenopex.cfm.
- ↑ "Drug Approval Package: Xopenex HFA (Levalbuterol Tartrate) NDA #021730". https://www.accessdata.fda.gov/drugsatfda_docs/nda/2005/021730s000TOC.cfm.
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