salbutamol

1 : 1 mixture (racemate) Salbutamol
Systematic (IUPAC) name
(RS)-4-[2-(tert-butylamino)-1-hydroxyethyl]-2-(hydroxymethyl)phenol
Identifiers
CAS number	18559-94-9
ATC code	R03AC02 R03CC02
PubChem	2083
DrugBank	APRD00553
ChemSpider	1999
Chemical data
Formula	C13H21NO3
Mol. mass	239.311
SMILES	eMolecules & PubChem
Pharmacokinetic data
Bioavailability	?
Metabolism	Hepatic
Half life	1.6 hours
Excretion	Renal
Therapeutic considerations
Pregnancy cat.	A(AU) C(US)
Legal status	Pharmacist Only (S3)(AU) ?(CA) POM(UK) ℞-only(US)
Routes	Oral, inhalational, IV
Y(what is this?)  (verify)

Ventolin HFA inhaler made by GSK

Asthalin HFA inhaler made by Cipla (India)

Salbutamol (INN) or albuterol (USAN) is a short-acting β₂-adrenergic receptor agonist used for the relief of bronchospasm in conditions such as asthma and chronic obstructive pulmonary disease. It is marketed by GlaxoSmithKline as Ventolin, Aerolin or Ventorlin depending on the market; by Cipla as Asthalin; by Schering-Plough as Proventil and by Teva as ProAir.

Salbutamol was the first selective Β2-receptor agonist to be marketed, in 1968. It was first sold by Allen & Hanburys under the brand name Ventolin. The drug was an instant success, and has been used for the treatment of asthma ever since.^[1]

Salbutamol sulfate is usually given by the inhaled route for direct effect on bronchial smooth muscle. This is usually achieved through a metered dose inhaler (MDI), nebuliser or other proprietary delivery devices (e.g. Rotahaler or Autohaler). In these forms of delivery, the maximal effect of Salbutamol can take place within five to twenty minutes of dosing, though some relief is immediately seen. Salbutamol can also be given orally as an inhalant or intravenously.

Clinical use

Salbutamol is specifically indicated in the following conditions:

• Acute asthma
• Symptom relief during maintenance therapy of asthma and other conditions with reversible airways obstruction (including COPD and bronchitis)
• Protection against exercise-induced asthma
• Can be aerosolized with a nebulizer for patients with cystic fibrosis, along with ipratropium bromide, acetylcysteine, and pulmozyme.
• Subtypes of congenital myasthenic syndromes associated to mutations in Dok-7.

As a β₂-agonist, salbutamol also finds use in obstetrics. Intravenous salbutamol can be used as a tocolytic to relax the uterine smooth muscle to delay premature labour. While preferred over agents such as atosiban and ritodrine, its role has largely been replaced by the calcium-channel blocker nifedipine which is more effective, better tolerated and orally administered.^[2]

In an emergency, EMS providers consider the administration of salbutamol when they see active wheezing, bronchospasm and a past diagnosis of asthma. The drug is most often administered through a nebulizer with 6 liters per minute of oxygen. A normal dose is about 1.25 mg in 3 mL of respiratory saline.

Side effects / health consequences

The most common side effects are of fine tremor, nervousness, headache, muscle cramps, dry mouth, and palpitation.^[3] Other symptoms may be tachycardia (rapid heart rate), arrhythmias, flushing, myocardial ischaemia, and disturbances of sleep and behaviour.^[3] Rarely occurring, but of importance, are allergic reactions of paradoxical bronchospasm, urticaria, angioedema, hypotension, and collapse, whilst high doses may cause hypokalaemia (low potassium levels), especially in patients with renal failure and those on certain diuretics and xanthine derivaties.^[3]

Ban of CFC-containing inhalers

The U.S. Food & Drug Administration in April 2005 mandated that all (including salbutamol) inhalers containing chlorofluorocarbons (CFCs) will be prohibited in the United States as of December 31, 2008.^[4] CFC inhalers had previously been given "essential use" status, exempting it from a CFC-production ban, however in accordance with the Montreal Protocol they will be phased out; in many other countries patients have been transitioned to non-CFC based inhalers using hydrofluoroalkane (HFA) propellant. Pharmaceutical manufacturers are expected to produce adequate supplies of alternative (HFA) inhalers by 2009.^{[citation needed]}

One drawback of this transition to HFA inhalers is that, due to patent restrictions, all HFA salbutamol inhalers are "brand-name" (ProAir, Proventil, and Ventolin). They cost approximately $20 more per inhaler than existing generic CFC salbutamol inhalers. These new formulations are patented. An industry consortium was formed to spread the costs of the FDA safety studies to get propellants such as 134a and 227 approved.^[5]

Generic HFA salbutamol inhalers are not expected on the United States market until 2012 due to existing patents.^[6]

Salbutamol is widely used, and accounts for anywhere from 78% of all bronchodilator prescriptions in 2005 to 85% in 2008.^[7] However, patients in the United States who cannot tolerate the HFA salbutamol inhalers will not have a single salbutamol alternative available to them domestically after December 31, 2008.^[8] The FDA did not approve any alternatives to HFA and there are few standard inhaled lung medications in the United States that come in Dry Powder Inhaler (DPI) versions. Noticeably missing is salbutamol in DPI form in the United States, although it is available in most of the rest of the world in salbutamol DPIs.

Diet and bodybuilding use

Salbutamol is taken by some as an alternative to Clenbuterol for purposes of fat burning.^[9]

References

Additional notes

1. Moore NG, Pegg GG, Sillence MN (September 1994). "Anabolic effects of the beta 2-adrenoceptor agonist salmeterol are dependent on route of administration". Am. J. Physiol. 267 (3 Pt 1): E475–84. PMID 7943228. http://ajpendo.physiology.org/cgi/pmidlookup?view=reprint&pmid=7943228. 
2. Schiffelers SL, Saris WH, Boomsma F, van Baak MA (May 2001). "beta(1)- and beta(2)-Adrenoceptor-mediated thermogenesis and lipid utilization in obese and lean men". J. Clin. Endocrinol. Metab. 86 (5): 2191–9. doi:10.1210/jc.86.5.2191. PMID 11344226. http://jcem.endojournals.org/cgi/pmidlookup?view=long&pmid=11344226. 
3. van Baak MA, Mayer LH, Kempinski RE, Hartgens F (July 2000). "Effect of salbutamol on muscle strength and endurance performance in nonasthmatic men". Med Sci Sports Exerc 32 (7): 1300–6. doi:10.1097/00005768-200007000-00018. PMID 10912897. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0195-9131&volume=32&issue=7&spage=1300. 
4. Caruso JF, Hamill JL, De Garmo N (February 2005). "Oral albuterol dosing during the latter stages of a resistance exercise program". J Strength Cond Res 19 (1): 102–7. doi:10.1519/R-14793.1. PMID 15705021. 
5. Caruso JF, Signorile JF, Perry AC, et al. (November 1995). "The effects of albuterol and isokinetic exercise on the quadriceps muscle group". Med Sci Sports Exerc 27 (11): 1471–6. PMID 8587482. 
6. Martineau L, Horan MA, Rothwell NJ, Little RA (November 1992). "Salbutamol, a beta 2-adrenoceptor agonist, increases skeletal muscle strength in young men". Clin. Sci. 83 (5): 615–21. PMID 1335400. S
7. Desaphy JF, Pierno S, De Luca A, Didonna P, Camerino DC (March 2003). "Different ability of clenbuterol and salbutamol to block sodium channels predicts their therapeutic use in muscle excitability disorders". Mol. Pharmacol. 63 (3): 659–70. doi:10.1124/mol.63.3.659. PMID 12606775. http://molpharm.aspetjournals.org/cgi/pmidlookup?view=long&pmid=12606775. 
8. Maki KC, Skorodin MS, Jessen JH, Laghi F (June 1996). "Effects of oral albuterol on serum lipids and carbohydrate metabolism in healthy men". Metab. Clin. Exp. 45 (6): 712–7. PMID 8637445. 

External links

• Volmax Drug Information
• Side Effects