Zafirlukast

Zafirlukast

File:Zafirlukast.svg
File:Zafirlukast.png
Systematic (IUPAC) name
cyclopentyl {3-​[2-​methoxy-​4-​({[(2-​methylphenyl)​sulfonyl]​amino}​carbonyl)​benzyl]-​1-​methyl-​1H-​indol-​5-​yl}​carbamate
Clinical data
Pregnancy category	B1 (Au), B (U.S.)
Routes of administration	Oral
Legal status
Legal status	POM (UK)
Pharmacokinetic data
Bioavailability	Unknown
Protein binding	99%
Metabolism	Hepatic (CYP2C9-mediated)
Biological half-life	10 hours
Excretion	Biliary
Identifiers
CAS Number	107753-78-6
ATC code	R03DC01 (WHO)
PubChem	CID 5717
DrugBank	APRD00377
Chemical data
Formula	C31H33N3O6S
Molar mass	575.676 g/mol[[]]
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Zafirlukast is an oral leukotriene receptor antagonist (LTRA) for the maintenance treatment of asthma, often used in conjunction with an inhaled steroid and/or long-acting bronchodilator. It is available as a tablet and is usually dosed twice daily. Another leukotriene receptor antagonist is montelukast (Singulair), taken once daily. Zileuton (Zyflo), also used in the treatment of asthma via its inhibition of 5-lipoxygenase, is taken four times per day.

Zafirlukast blocks the action of the cysteinyl leukotrienes on the CysLT1 receptors, thus reducing constriction of the airways, build-up of mucus in the lungs and inflammation of the breathing passages.

Zafirlukast is marketed by Astra Zeneca with the brand names Accolate, Accoleit, and Vanticon. It was the first LTRA to be marketed in the USA and is now approved in over 60 countries, including the UK, Japan, Taiwan, Italy, Spain, Canada, Brazil, China and Turkey.

Pharmacokinetics

Healthy young men who received a single oral 40 mg dose attained peak plasma zafirlukast concentrations that averaged 607 μg/L at 3.4 hours. The elimination half-life ranged from 12 to 20 hours. In another study involving a 20 mg single oral dose in healthy men, the elimination half-life averaged 5.6 hours.

Special warnings

A letter was submitted to the FDA by Zeneca Pharmaceuticals on July 22, 1997, notifying them of a change in product labeling that includes the following potential reaction in patients undergoing a dosage reduction of oral steroids who are currently taking zafirlukast:

PRECAUTIONS-Eosinophilic Conditions: The reduction of the oral steroid dose, in some patients on ACCOLATE therapy, has been followed in rare cases by the occurrence of eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy sometimes presenting as Churg–Strauss syndrome, a systemic eosinophilic vasculitis. Although a causal relationship with ACCOLATE has not been established, caution is required when oral steroid reduction is being considered.¹

External links

• Accolate, Accoleit, Vanticon (manufacturer's website)
• Zafirlukast (patient information)

es:Zafirlukast pt:Zafirlucaste