Levosalbutamol isindicated for the treatment or prevention of bronchospasm in people aged four years of age and older with reversible obstructive airway disease.[1]
Evidence is inconclusive regarding the efficacy of levosalbutamol versussalbutamol (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).[5][6]
A 2013systematic 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."[5]
Generally, levosalbutamol is well tolerated. Common mild side effects include an elevated heart rate, muscle cramps, and gastric upset (including heartburn and diarrhea).[7]
Symptoms of overdose in particular include: collapse into aseizure; chest pain (possible precursor of aheart attack); fast, pounding heartbeat, which may cause raised blood pressure (hypertension); irregular heartbeat (cardiac arrhythmia), which may cause paradoxical lowered blood pressure (hypotension); nervousness andtremor; headache; dizziness andnausea/vomiting; weakness or exhaustion (medical fatigue); dry mouth; andinsomnia.[7]
Rarer side effects may indicate a dangerous allergic reaction. These include: paradoxicalbronchospasm (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 tovoice hoarseness), or swelling of the extremities.[7]
Activation of β2 adrenergicreceptors on airway smooth muscle leads to the activation ofadenylate cyclase and to an increase in the intracellular concentration of3',5'-cyclic adenosine monophosphate (cyclic AMP). The increase in cyclic AMP is associated with the activation of proteinkinase A, which in turn, inhibits thephosphorylation ofmyosin and lowers intracellular ionic calcium concentrations, resulting in muscle relaxation.
Levosalbutamol relaxes the smooth muscles of all airways, from thetrachea 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 functionalagonist that relaxes the airway irrespective of the spasmogen involved, thereby protecting against allbronchoconstrictor 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 significantcardiovascular effect in some patients, as measured by pulse rate, blood pressure, and restlessness symptoms, and/orelectrocardiographic (ECG).
Levalbuterol was approved in the United States as a solution to be used with anebulizer device in March 1999,[11] and in March 2005, became available in a formulation with ametered-dose inhaler under the brand name Xopenex HFA (levalbuteroltartrate inhalation aerosol).[12]
^abJat KR, Khairwa A (April 2013). "Levalbuterol versus albuterol for acute asthma: a systematic review and meta-analysis".Pulmonary Pharmacology & Therapeutics.26 (2):239–248.doi:10.1016/j.pupt.2012.11.003.PMID23207739.
^Punj A, Prakash A, Bhasin A (November 2009). "Levosalbutamol vs racemic salbutamol in the treatment of acute exacerbation of asthma".Indian Journal of Pediatrics.76 (11):1131–1135.doi:10.1007/s12098-009-0245-4.PMID20012785.S2CID11566782.
^abcAmerican Society of Health-System Pharmacists (1 September 2010)."Levalbuterol Oral Inhalation".MedlinePlus. Bethesda, Maryland: U.S. National Library of Medicine, National Institutes of Health. Retrieved7 January 2015.
^Schreck DM, Babin S (November 2005). "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.doi:10.1016/j.ajem.2005.04.003.PMID16291438.
^Hendeles L, Hartzema A (September 2003). "Levalbuterol is not more cost-effective than albuterol for COPD".Chest.124 (3): 1176, author reply 1176–1176, author reply 1178.doi:10.1378/chest.124.3.1176.PMID12970057.