Formoterol

Formoterol

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Systematic (IUPAC) name
(RS,SR)-N-[2-hydroxy-5-[1-hydroxy-2-[1-(4-methoxyphenyl) propan-2-ylamino]ethyl] phenyl]formamide
Clinical data
Pregnancy category	AU: B3 US: C (Risk not ruled out)
Routes of administration	Oral, Inhalation
Legal status
Legal status	UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Protein binding	61–64%
Metabolism	Hepatic demethylation and glucuronidation (CYP2D6, CYP2C19, CYP2C9 and CYP2A6 involved)
Biological half-life	10 hours
Excretion	Renal and fecal
Identifiers
CAS Number	73573-87-2
ATC code	R03AC13 (WHO)
PubChem	CID 3410
DrugBank	APRD00641
Chemical data
Formula	C19H24N2O4
Molar mass	344.405 g/mol[[]]
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Formoterol (INN) or eformoterol (former BAN) is a long-acting β₂-agonist used in the management of asthma and/or chronic obstructive pulmonary disease (COPD). It is marketed in four forms: a dry-powder inhaler (DPI), metered dose inhaler (MDI), an oral tablet, and as an inhalation solution, under various trade names including Foradil/Foradile (Schering-Plough in the U.S., Novartis rest of world), Oxeze (AstraZeneca), Atock (Astellas), Atimos Modulite (Trinity-Chiesi) and Perforomist (Dey).

Formoterol is a long-acting β₂ agonist (LABA), which has an extended duration of action (up to 12 hours) compared to short-acting β₂ agonists such as salbutamol, which are effective for 4–6 hours. LABAs such as formoterol are used as "symptom controllers" to supplement prophylactic corticosteroid therapy (e.g. fluticasone). A "reliever" short-acting β₂ agonist (e.g. salbutamol) is still required, since LABAs are not recommended for the treatment of acute asthma.

Mechanism of action

Inhaled formoterol works like other β₂-agonists, causing bronchodilation by relaxing the smooth muscle in the airway so as to treat the exacerbation of asthma. The long duration of formoterol action occurs because the formoterol molecules initially diffuse into the plasma membrane of the lung cells, and then are slowly released back outside, where they can come into contact with β₂ adrenergic receptors. Formoterol has been demonstrated to have a faster onset of action than salmeterol as a result of 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.

Safety

In November 2005, the US FDA released a health advisory alerting the public to findings that show the use of long-acting β₂-agonists could lead to a worsening of wheezing symptoms in some patients.

Currently available long-acting β₂-agonists include salmeterol, formoterol, bambuterol, and sustained-release oral salbutamol. Combinations of inhaled steroids and long-acting bronchodilators are becoming more widespread – combination preparations include fluticasone/salmeterol and budesonide/formoterol.

See also

• Arformoterol
• Budesonide/formoterol
• Beclomethasone/formoterol

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