Zafirlukast

Zafirlukast is a prescription medication used to treat the symptoms of Asthma.

• Zafirlukast is available under the following different brand names: Accolate

Common side effects of Zafirlukast include:

• nausea,
• diarrhea,
• stomach pain,
• headache, and
• cold symptoms (stuffy nose, sneezing, sore throat)

Serious side effects of Zafirlukast include:

• hives,
• blisters,
• severe itching,
• difficulty breathing,
• swelling of the face, lips, tongue, or throat,
• depressed mood,
• unusual thoughts or behavior,
• severe sinus pain,
• sinus congestion,
• numbness or tingly feeling in the arms or legs,
• worsening or no improvement in the asthma,
• nausea,
• upper stomach pain,
• tired feeling,
• loss of appetite,
• dark urine,
• clay-colored stools,
• yellowing of the skin or eyes (jaundice),
• skin rash,
• bruising,
• severe tingling,
• pain,
• muscle weakness,
• new or worsening cough,
• fever, and
• trouble breathing

Rare side effects of Zafirlukast include:

• none

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheartedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult and pediatric dosage

Tablets

• 10 mg
• 20 mg

Asthma

Adult dosage

• 20 mg orally twice daily

Pediatric dosage

• Children below 5 years: Safety and efficacy not established
• 5-12 years: 10 mg orally twice daily
• Children above 12 years: 20 mg orally twice daily

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Zafirlukast has severe interactions with no other drugs.
• Zafirlukast has serious interactions with at least 22 other drugs.
• Zafirlukast has moderate interactions with at least 112 other drugs.
• Zafirlukast has moderate interactions with at least 71 other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Hypersensitivity
• Hepatic impairment, including cirrhosis; Cmax and AUC Approximately 50-60% greater than those of normal adults

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Zafirlukast?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Zafirlukast?”

Cautions

• Increased risk of infection if age above 55 years
• Not indicated for use in the reversal of bronchospasm in acute asthma attacks, including status asthmaticus; therapy can be continued during acute exacerbations of asthma
• Coadministration of zafirlukast with warfarin results in a clinically significant increase in prothrombin time (PT); patients on oral warfarin anticoagulant therapy and this drug should have their prothrombin times monitored closely and anticoagulant dose adjusted accordingly
• Indicated for the chronic treatment of asthma; should be taken regularly as prescribed, even during symptom-free periods; this drug is not a bronchodilator and should not be used to treat acute episodes of asthma
• Patients receiving therapy should be instructed not to decrease the dose or stop taking any other antiasthma medications unless instructed by a physician
• Patients should be instructed to notify their physician if neuropsychiatric events occur while using this drug; breast-feeding women should be instructed not to take this medication; alternative antiasthma medication should be considered in such patients
• The bioavailability of this medication may be decreased when taken with food; patients should be instructed to take the medication at least 1 hour before or 2 hours after meals
• Eosinophilic conditions
  • In rare cases, patients with asthma on this medication may present with systemic eosinophilia, eosinophilic pneumonia, or clinical features of vasculitis consistent with Churg-Strauss syndrome, a condition which is often treated with systemic steroid therapy; physicians should be alert to eosinophilia, vasculitis rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy presenting in their patients
  • These events have usually, but not always, been associated with reductions and/or withdrawal of steroid therapy; the possibility that this medication may be associated with the emergence of Churg-Strauss syndrome can neither be excluded nor established
• Neuropsychiatric events
  • Neuropsychiatric events have been reported in adult, adolescent, and pediatric patients taking this medication; post-marketing reports include insomnia and depression
  • The clinical details of some post-marketing reports involving this medication appear consistent with a drug-induced effect; patients and prescribers should be alert for neuropsychiatric events; patients should be instructed to notify their prescriber if these changes occur
  • Prescribers should carefully evaluate the risks and benefits of continuing treatment with this medication if such events occur
• Hepatotoxicity
  • Cases of life-threatening hepatic failure reported; cases of liver injury without other attributable cause reported from post-marketing adverse event surveillance of patients who have received recommended dose (40 mg/day)
  • In most, but not all post-marketing reports, the patient’s symptoms abated, and the liver enzymes returned to normal or near normal after stopping therapy
  • In rare cases, patients have either presented with fulminant hepatitis or progressed to hepatic failure, liver transplantation, and death; in rare post-marketing cases, no clinical symptoms, or signs suggestive of liver dysfunction were reported to precede the latter observations
  • Physicians may consider the value of liver function testing.; periodic serum transaminase testing has not proven to prevent serious injury, but it is generally believed that early detection of drug-induced hepatic injury along with the immediate withdrawal of the suspect drug enhances the likelihood of recovery
  • Patients should be advised to be alert for signs and symptoms of liver dysfunction (.g, right upper quadrant abdominal pain, nausea, fatigue, lethargy, pruritus, jaundice, flu-like symptoms, and anorexia) and to contact their physician immediately if they occur; ongoing clinical assessment of patients should govern physician interventions, including diagnostic evaluations and treatment
  • If liver dysfunction is suspected based upon clinical signs or symptoms (.g, right upper quadrant abdominal pain, nausea, fatigue, lethargy, pruritus, jaundice, flu-like symptoms, anorexia, and enlarged liver), should be discontinued
  • Liver function tests, in particular serum ALT, should be measured immediately and the patient managed; accordingly, if liver function tests are consistent with hepatic dysfunction, therapy should not be resumed; patients in whom therapy was withdrawn because of hepatic dysfunction where no other attributable cause is identified should not be re-exposed to the drug

Pregnancy and Lactation

• No teratogenicity was observed at oral doses up to 1600 mg/kg/day in mice (approximately 160 times the maximum recommended daily oral dose in adults on an mg/m2 basis), up to 2000 mg/kg/day in rats (approximately 410 times the maximum recommended daily oral dose in adults on mg/m2 basis) and up to 2000 mg/kg/day in cynomolgus monkeys (which resulted in approximately 20 times the exposure to drug plus metabolites compared to that from the maximum recommended daily oral dose in adults based on comparison of the AUC values)
• At an oral dose of 2000 mg/kg/day in rats, maternal toxicity and deaths were seen with an increased incidence of early fetal resorption; spontaneous abortions occurred in cynomolgus monkeys at the maternally toxic oral dose of 2000 mg/kg/day; there are no adequate and well-controlled trials in pregnant women; because animal reproduction studies are not always predictive of human response, this medication should be used during pregnancy only if needed
• Lactation
  • This medication is excreted in breast milk; following repeated 40 mg twice-a-day dosing in healthy women, average steady-state concentrations in breast milk were 50 ng/mL compared to 255 ng/mL in plasma; because of the potential for tumorigenicity shown in mouse and rat studies and the enhanced sensitivity of neonatal rats and dogs to adverse effects of this medication should not be administered to breast-feeding mothers