Clinical data | |
---|---|
Trade names | Accolate [1] |
AHFS/Drugs.com | Monograph |
MedlinePlus | a697007 |
License data |
|
Pregnancy category |
|
Routes of administration | Oral |
ATC code | |
Legal status | |
Legal status |
|
Pharmacokinetic data | |
Bioavailability | Unknown |
Protein binding | >99% (albumin) [1] |
Metabolism | Hepatic (CYP2C9-mediated) |
Metabolites | hydroxylated metabolites [1] |
Elimination half-life | 10 hours |
Excretion | Fecal [1] |
Identifiers | |
| |
CAS Number | |
PubChem CID | |
IUPHAR/BPS | |
DrugBank | |
ChemSpider | |
UNII | |
KEGG | |
ChEBI | |
ChEMBL | |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.189.989 |
Chemical and physical data | |
Formula | C31H33N3O6S |
Molar mass | 575.68 g·mol−1 |
3D model (JSmol) | |
Melting point | 138 to 140 °C (280 to 284 °F) |
| |
| |
(verify) |
Zafirlukast is an orally administered leukotriene receptor antagonist (LTRA) used for the chronic treatment of asthma. While zafirlukast is generally well tolerated, headache and stomach upset often occur. Some rare side effects can occur, which can be life-threatening, such as liver failure. Churg-Strauss syndrome has been associated with zafirlukast, but the relationship isn't thought to be causative in nature. Overdoses of zafirlukast tend to be self-limiting.
Zafirlukast, like other LTRAs, works by inhibiting the immune system. Through its action on inflammatory cells in the lungs, zafirlukast reduces the production of inflammatory mediators that are implicated in the pathogenesis of asthma. Zafirlukast is extensively hepatically metabolized by an enzyme called CYP2C9. Zafirlukast inhibits the action of CYP3A4, leading to drug–drug interactions with other drugs that are metabolized by CYP3A4. Genetic differences in LTC4 synthase and CYP2C9 may predict how a person reacts to zafirlukast treatment.
Zafirlukast (brand name Accolate) was the first cysteinyl leukotriene receptor antagonist approved in the United States. It is now approved in many other countries under other brand names.
Zafirlukast is FDA-approved for the prevention and treatment of asthma in adults and children older than 5 years old. [1] Like other leukotriene receptor antagonists, zafirlukast is thought to be useful for the long-term treatment of asthma, but it is generally less effective than inhaled glucocorticoids as monotherapy (which are the standard of care) or long-acting beta-2 agonists in combination therapy. [2] Notably, zafirlukast is ineffective in the event of an acute asthma attack. [1]
There are two dosage forms for zafirlukast, notable for their age-adjustments. The 20 mg tablet is for adults and children older than age 12, whereas the 10 mg tablet is for children between the ages of 5 and 12. [1] Tablets should be stored at room temperature, out of direct sunlight, and away from sources of moisture. [1]
Tablets are for oral administration only. [1]
As a general rule, leukotriene receptor antagonists like zafirlukast are more effective in children that are younger and whose asthma is less atopic. [3] Atopy refers to a predisposition towards developing allergic conditions, including asthma, hay fever, and eczema. [4]
The hepatic clearance of zafirlukast is impaired in adults 65 years of age and older, resulting in a 2–3 fold increase in the maximum plasma concentration and the total area under the curve. Zafirlukast may increase the risk for infections (7.0% vs 2.9%, zafirlukast vs. placebo incidence respectively), especially lower respiratory tract infections, in older adults, though the infections noted were not severe. [1]
Zafirlukast is considered to be "pregnancy category B." This is due, in part, to the wide safety margin of zafirlukast in animal studies investigating teratogenicity. No teratogenicity has been observed in doses up to 2000 mg/kg/day in cynomolgus monkeys, representing an equivalent 20x exposure of the maximum recommended daily oral dose in human adults. However, spontaneous abortions occurred in cynomolgus monkeys at 2000 mg/kg/day, though the dose itself was maternally toxic. [1]
There is limited research on the use of zafirlukast in women whom are breastfeeding. [5] Based on data from the manufacturer, it is expected that 0.6% of the maternal weight-adjusted dose would reach a breastfed infant, though the effects in the infant are unknown. [5]
Renal impairment does not appear to affect the pharmacokinetic profile of zafirlukast. [1]
The hepatic clearance of zafirlukast is impaired by significant hepatic impairment. Cirrhosis of the liver can result in an increase in the maximum plasma concentration and the total area under the curve (a measure of drug exposure) by 50–60%. [1]
Zafirlukast is contraindicated in people that are hypersensitive or allergic to it. [1]
Zafirlukast is generally well tolerated, though headache and gastrointestinal (GI) upset can occur. The incidence of headache is between 12 and 20%, which is similar to the incidence of headache found in patients taking placebos in the studies that lead to zafirlukast's approval. GI upset may include nausea, stomach discomfort/pain, and diarrhea. GI complaints can be lessened by taking zafirlukast with food, though this can dramatically impair the amount of drug that gets absorbed into the body (see the section on drug-food interactions below). [6]
Other common side effects include flu-like symptoms, sleep disturbances (abnormal dreams, insomnia), hallucinations, and daytime drowsiness. [6]
Neuropsychiatric side effects have been reported with the use of zafirlukast and other LTRAs. While some side effects are less severe (e.g. abnormal dreams), others are more serious (e.g. hallucinations, tremor, suicidality). These effects were discovered through post-marketing reports, as the initial trials were not designed to monitor for neuropsychiatric side effects. [7]
Zafirlukast can also cause rare but serious side effects like acute liver injury. [8] Zafirlukast-induced hepatotoxicity generally occurs within the first 2–6 months of initiating therapy, though cases have been reported up to 13 months after starting zafirlukast. [8] Zafirlukast-induced hepatotoxicity is characterized by a spectrum of liver damage symptoms, including fatigue, nausea, and right upper quadrant pain followed by dark urine, jaundice and pruritus. [8] Liver enzyme elevations are common, and the pattern usually reflects hepatocellular damage, resembling acute viral hepatitis. [8] It is unclear how the hepatotoxicity occurs, but it may be due to a metabolic intermediate of zafirlukast, since it is metabolized in the liver through the enzyme CYP2C9. When it does occur it can be fatal, and reexposure with zafirlukast may result in a worse injury. [8] Switching zafirlukast to another medication in the same class (e.g. montelukast) or in the related class of 5-lipoxygenase inhibitors can be attempted, but caution should be employed. [8]
According to the "Dear Health Care Provider" letter from AstraZeneca, zafirlukast-induced hepatotoxicity has occurred predominantly in females. [9]
Several cases of Churg-Strauss syndrome, also known as allergic angiitis and granulomatosis, have been reported with the use of zafirlukast, montelukast, pranlukast, and other asthma medications. [10] When Churg-Strauss syndrome occurs, it tends to occur in people with long-standing asthma and sinus inflammation, chronic oral corticosteroid use, and the recent initiation of a new anti-asthma therapy (like zafirlukast) in conjunction with tapering the corticosteroids. [10] While the exact etiology of the development of Churg-Strauss symptoms in proximity to initiating zafirlukast is unknown, it is thought that withdrawal of chronic corticosteroids "unmasks" the previously undetected disease. [10] Because corticosteroid withdrawal often happens while starting a new anti-asthma medication (like zafirlukast), this explains the rare but notable association. [10] These cases may represent misdiagnosed asthma, as Churg-Strauss syndrome can induce symptoms of airway obstruction that are akin to an acute asthma exacerbation. [10] As these asthma-like symptoms are reduced by zafirlukast, the symptoms of Churg-Strauss (e.g. neuropathy) increase due to the lack of the broader, anti-inflammatory coverage that the steroid was providing. [10]
The highest overdose reported with zafirlukast is 200 mg. All overdose patients have survived. Symptoms reported included rash and upset stomach. [1]
Zafirlukast is an inhibitor of the hepatic drug-metabolizing enzyme cytochrome P450 family 3 subfamily A member 4 (CYP3A4). [1] Zafirlukast may increase the concentration of drugs that are metabolized through CYP3A4, such as the anticoagulant medication warfarin and the antiepileptic drugs phenytoin and carbamazepine. [1]
The oral absorption (bioavailability) of zafirlukast is decreased by 40% when it is taken with high fat or high protein meals. [1] To avoid this interaction, zafirlukast should be taken on an empty stomach. [6] An empty stomach is classified as an hour before, or two hours after, consuming a meal. [1]
Zafirlukast is an antagonist of cysteinyl leukotriene receptor 1 (CysLT1), a receptor found throughout the smooth muscle of the lungs, within interstitial lung macrophages (white blood cells that operate in the interstitial space of the lungs), and rarely in epithelial cells. [11] CystLT1 is a receptor for a specific class of leukotrienes that contain the amino acid cysteine. [2] These cysteinyl leukotrienes include leukotriene C4, leukotriene D4, and leukotriene E4, all of which are produced by inflammatory cells like eosinophils, basophils, and macrophages in the lungs. [2] Through their action on CysLT1 these leukotrienes can trigger bronchoconstriction, a state in which the bronchial passages of the lungs constrict, [12] leading to the characteristic, reactive airway symptoms associated with bronchial asthma. [2] The other pro-inflammatory effects of leukotrienes, such as their inhibition of mucus clearance and their stimulation of mucus secretion and edema, are thought to play a role in the characteristic symptoms of allergic rhinitis (also called hay fever [13] ). [2] By inhibiting the action of these specific leukotrienes, zafirlukast is thought to exert an anti-inflammatory effect against leukotriene-mediated inflammatory conditions. [2]
Zafirlukast is rapidly absorbed into the bloodstream following oral administration, reaching peak plasma levels within 3 hours of taking the dose. [1] The peak plasma level is the maximum concentration of zafirlukast in the blood. [14]
Zafirlukast is moderately distributed into the body's tissues, with an apparent steady state volume of distribution of 70 liters. [1] Zafirlukast is highly plasma protein bound, 99% bound to albumin. [1] Albumin is the most abundant protein found in human plasma and is capable of carrying and transporting drugs (like zafirlukast) throughout the body. [15] In vivo research indicates that zafirlukast has low blood–brain barrier penetration. [1] The blood–brain barrier is a protective system that prevents many chemicals from entering the brain. [16]
Zafirlukast undergoes extensive hepatic metabolism into inactive metabolites. [1] Zafirlukast is primarily metabolized by the enzyme CYP2C9 to a hydroxylated metabolite. [1]
Zafirlukast is primarily cleared through biliary excretion at a rate of 20 liters/hour. Zafirlukast is undetectable in urine. The mean terminal half-life ranges 8–16 hours, following linear kinetics up to doses of 80 mg. [1]
Genetic polymorphisms in the LTC4 synthase promoter may predict response to zafirlukast. The single-nucleotide polymorphism (SNP) A444C (the wild-type DNA base adenine, at the 444th position on the gene, is mutated; cytosine is there instead), which is associated with a severe asthma phenotype, has been shown to decrease the clinical response to zafirlukast (both when the genetic alteration was heterozygous or homozygous). [17]
Zafirlukast is metabolized through the hepatic enzyme CYP2C9. SNPs that decrease the function of CYP2C9 (such as CYP2C9*3 and CYP2C9*13) may decrease the hepatic clearance of zafirlukast, leading to increased exposure of zafirlukast. [18] Notably, the CYP2C9*3 polymorphism is more commonly encountered in people of south/central Asian ancestry (10.165%) compared to people of Caucasian (7.083%), African American (1.170%), African (1.033%), middle eastern (9.312%), and east Asian (3.365%) ancestry. [19]
Zafirlukast can be synthesized by the following method: [20]
Pure zafirlukast is described as a fine, white to pale yellow, amorphous powder. It is practically insoluble in water, slightly soluble in methanol, and freely soluble in tetrahydrofuran, dimethylsulfoxide, and acetone. [1]
Zafirlukast was the first cysteinyl leukotriene receptor antagonist approved in the United States. [10] Zafirlukast was approved in 1996. [10]
While preliminary evidence suggests that zafirlukast may reduce healthcare costs, the cost-effectiveness of using zafirlukast has not been established. [21]
A | Accolate, Accoleit, Aeronix |
B | Benalucost |
C | |
D | |
E | |
F | Freesy |
G | |
H | |
I | |
J | |
K | |
L | |
M | Monokast |
N | |
O | Olmoran |
P | |
Q | |
R | |
S | |
T | |
U | |
V | Ventair |
W | |
X | |
Y | |
Z | Zafnil, Zalukast, Zukast |
There is some research to suggest that zafirlukast actually acts as a partial inverse agonist at the CysLT1 receptor, though zafirlukast is still classified as an antagonist at this receptor. The possible clinical significance of this effect, if true, is unknown. [17]
There is some evidence that suggests that zafirlukast may be beneficial in the treatment of chronic urticaria (hives), whether due to a known cause such as cold-exposure or due to an unknown cause (idiopathic). [17] A pilot study indicated that zafirlukast may be of some benefit in cystic fibrosis. [17] In the setting of chronic obstructive pulmonary disorder (COPD), a disease characterized by chronic inflammation of the lungs, zafirlukast has been shown to improve lung function. [17]
Zafirlukast is sometimes used for the treatment of bronchial asthma in cats. [23]
Anti-inflammatory or antiphlogistic is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as opposed to opioids, which affect the central nervous system to block pain signaling to the brain.
Leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase.
Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as allergic granulomatosis, is an extremely rare autoimmune condition that causes inflammation of small and medium-sized blood vessels (vasculitis) in persons with a history of airway allergic hypersensitivity (atopy).
Cimetidine, sold under the brand name Tagamet among others, is a histamine H2 receptor antagonist that inhibits stomach acid production. It is mainly used in the treatment of heartburn and peptic ulcers.
Zileuton (trade name Zyflo) is an orally active inhibitor of 5-lipoxygenase, and thus inhibits leukotrienes (LTB4, LTC4, LTD4, and LTE4) formation, used for the maintenance treatment of asthma. Zileuton was introduced in 1996 by Abbott Laboratories and is now marketed in two formulations by Cornerstone Therapeutics Inc. under the brand names Zyflo and Zyflo CR. The original immediate-release formulation, Zyflo, is taken four times per day. The extended-release formulation, Zyflo CR, is taken twice daily.
Triamcinolone is a glucocorticoid used to treat certain skin diseases, allergies, and rheumatic disorders among others. It is also used to prevent worsening of asthma and COPD. It can be taken in various ways including by mouth, injection into a muscle, and inhalation.
Montelukast, sold under the brand name Singulair among others, is a medication used in the maintenance treatment of asthma. It is generally less preferred for this use than inhaled corticosteroids. It is not useful for acute asthma attacks. Other uses include allergic rhinitis and hives of long duration. For allergic rhinitis it is a second-line treatment.
Doxepin is a medication belonging to the tricyclic antidepressant (TCA) class of drugs used to treat major depressive disorder, anxiety disorders, chronic hives, and insomnia. For hives it is a less preferred alternative to antihistamines. It has a mild to moderate benefit for sleeping problems. It is used as a cream for itchiness due to atopic dermatitis or lichen simplex chronicus.
Fluticasone propionate, sold under the brand names Flovent and Flonase among others, is a steroid medication. When inhaled it is used for the long term management of asthma and COPD. In the nose it is used for hay fever and nasal polyps. It can also be used for mouth ulcers. It works by decreasing inflammation
Alpha-1 blockers constitute a variety of drugs that block the effect of catecholamines on alpha-1-adrenergic receptors. They are mainly used to treat benign prostatic hyperplasia (BPH), hypertension and post-traumatic stress disorder. Alpha-1 adrenergic receptors are present in vascular smooth muscle, the central nervous system, and other tissues. When alpha blockers bind to these receptors in vascular smooth muscle, they cause vasodilation.
Mometasone, also known as mometasone y 3 s, is a steroid medication used to treat certain skin conditions, hay fever, and asthma. Specifically it is used to prevent rather than treat asthma attacks. It can be applied to the skin, inhaled, or used in the nose. Mometasone furoate, not mometasone, is used in medical products.
Phenprocoumon is a long-acting blood thinner drug to be taken by mouth, and a coumarin derivative. It acts as a vitamin K antagonist and inhibits blood clotting (coagulation) by blocking synthesis of coagulation factors II, VII, IX and X. It is used for the prophylaxis and treatment of thromboembolic disorders such as heart attacks and pulmonary (lung) embolism. The most common adverse effect is bleeding. The drug interacts with a large number of other medications, including aspirin and St John's Wort. It is the standard coumarin used in Germany, Austria, and other European countries.
An antileukotriene, also known as leukotriene modifier and leukotriene receptor antagonist, is a medication which functions as a leukotriene-related enzyme inhibitor or leukotriene receptor antagonist and consequently opposes the function of these inflammatory mediators; leukotrienes are produced by the immune system and serve to promote bronchoconstriction, inflammation, microvascular permeability, and mucus secretion in asthma and COPD. Leukotriene receptor antagonists are sometimes colloquially referred to as leukasts.
Arachidonate 5-lipoxygenase, also known as ALOX5, 5-lipoxygenase, 5-LOX, or 5-LO, is a non-heme iron-containing enzyme that in humans is encoded by the ALOX5 gene. Arachidonate 5-lipoxygenase is a member of the lipoxygenase family of enzymes. It transforms essential fatty acids (EFA) substrates into leukotrienes as well as a wide range of other biologically active products. ALOX5 is a current target for pharmaceutical intervention in a number of diseases.
Cysteinyl leukotriene receptor 1, also termed CYSLTR1, is a receptor for cysteinyl leukotrienes (LT). CYSLTR1, by binding these cysteinyl LTs contributes to mediating various allergic and hypersensitivity reactions in humans as well as models of the reactions in other animals.
Cysteinyl leukotriene receptor 2, also termed CYSLTR2, is a receptor for cysteinyl leukotrienes (LT). CYSLTR2, by binding these cysteinyl LTs contributes to mediating various allergic and hypersensitivity reactions in humans. However, the first discovered receptor for these CsLTs, cysteinyl leukotriene receptor 1 (CysLTR1), appears to play the major role in mediating these reactions.
VEGFR-2 inhibitor, also known as kinase insert domain receptor(KDR) inhibitor, are tyrosine kinase receptor inhibitors that reduce angiogenesis or lymphangiogenesis, leading to anticancer activity. Generally they are small, synthesised molecules that bind competitively to the ATP-site of the tyrosine kinase domain. VEGFR-2 selective inhibitor can interrupt multiple signaling pathways involved in tumor, including proliferation, metastasis and angiogenesis.
Cysteinyl-leukotriene type 1 receptor antagonists, also known as CysLT1 antagonists, are a class of drugs that hinder the action of leukotriene by binding to the receptor with antagonistic action without having an agonistic effect. These drugs are used to treat asthma, relieve individuals of seasonal allergies rhinitis and prevention of exercise-induced bronchoconstriction. There are currently three different types of drugs within the CysLT1 family, zafirlukast which was first on the market being released in 1996, montelukast which was released in 1998 and pranlukast which was released in 2007.
Fluticasone furoate/umeclidinium bromide/vilanterol, sold under the brand name Trelegy Ellipta among others, is a fixed-dose combination inhaled medication that is used for the maintenance treatment of chronic obstructive pulmonary disease (COPD). The medications work in different ways: fluticasone furoate is an inhaled corticosteroid (ICS), umeclidinium is a long-acting muscarinic antagonist (LAMA), and vilanterol is a long-acting beta-agonist (LABA).
Asthma triggers are factors or stimuli that provoke the exacerbation of asthma symptoms or increase the degree of airflow disruption, which can lead to an asthma attack. An asthma attack is characterized by an obstruction of the airway, hypersecretion of mucus and bronchoconstriction due to the contraction of smooth muscles around the respiratory tract. Its symptoms include a wide range of manifestations such as breathlessness, coughing, a tight chest and wheezing.
{{cite book}}
: |work=
ignored (help){{cite book}}
: |work=
ignored (help)Cmax is the maximum concentration of the drug achieved in the plasma following dose administration and Tmax is the time at which Cmax is attained.