Article: Salmeterol

Salmeterol
Systematic (IUPAC) name
2-(hydroxymethyl)-4- [1-hydroxy-2-[6-(4-phenylbutoxy) hexylamino]ethyl]-phenol
Identifiers
CAS number	89365-50-4
ATC code	R03AC12
PubChem	5152
DrugBank	APRD00277
Chemical data
Formula	C25H37NO4
Mol. weight	415.57
Pharmacokinetic data
Bioavailability	?
Protein binding	96%
Metabolism	CYP3A4
Half life	5.5 Hours
Excretion	?
Therapeutic considerations
Pregnancy cat.	?
Legal status	POM (UK), ℞-only (U.S.)
Routes	Inhalation

Salmeterol is a long-acting beta2-adrenergic receptor agonist drug that is currently prescribed for the treatment of asthma and chronic obstructive pulmonary disease COPD. It is currently available in both dry-powder inhalers (DPIs) and pressurised metered dose inhalers (pMDIs).

It is a long acting beta-adrenoceptor agonist (LABA), usually only prescribed for severe persistent asthma following previous treatment with a short-acting beta agonist such as salbutamol and is prescribed concurrently with a corticosteroid, such as beclometasone. The primary noticeable difference of salmeterol to salbutamol is that the duration of action lasts approximately 12 hours in comparison with 4–6 hours of salbutamol.

When used regularly every day as prescribed, inhaled formoterol decreases the number and severity of asthma attacks. However, it is not for use for relieving an asthma attack that has already started.

Inhaled salmeterol works like other beta 2-agonists, causing bronchodialation by relaxing the smooth muscle in the airway so as to treat the exacerbation of asthma. The long duration of formoterol action occurs by the formoterol molecules initially diffusing into the plasma membrane of the lung cells, and then slowly being released back outside the cell where they can come into contact with the beta-2 adrenoceptors. Formoterol has been demonstrated to have a faster onset of action than salmeterol as a result of a lower lipophilicity, and has also been demonstrated to be more potent—a 12 µg dose of formoterol has been demonstrated to be equivalent to a 50 µg dose of salmeterol.

Salmeterol was developed by the company GlaxoSmithKline in the 1980s and was released as Serevent in 1990.

In November of 2005, the American FDA released a health advisory[1], alerting the public to findings that show the use of Long-acting β₂-agonists could lead to a worsening of symptoms, and in some cases death.

Currently available long-acting beta₂-adrenoceptor agonists include salmeterol, formoterol, bambuterol, and sustained-release oral albuterol. Combinations of inhaled steroids and long-acting bronchodilators are becoming more widespread; the most common combination currently in use is fluticasone/salmeterol (Advair in the United States, and Seretide in the UK).

See also

• Asthma
• Beta2-adrenergic receptor agonist