Zafirlukast

About Zafirlukast

Zafirlukast blocks the action of leukotrienes, natural substances that cause swelling and tightening of the airways. The label covers the prevention and long-term treatment of asthma in adults and children 5 and older: 20 mg twice a day from age 12 and 10 mg twice a day for children 5 to 11, taken at least 1 hour before or 2 hours after meals because food lowers how much is absorbed. It is taken every day, including days without symptoms. It is not a bronchodilator and does not treat an attack, although it can be continued during a flare, so a quick-relief inhaler is still needed. Safety and effectiveness under age 5 are not established, and people 65 and older clear it more slowly, though the label sets no separate dose for them.

There is no boxed warning, but the label reports cases of life-threatening liver failure, and zafirlukast must not be taken with liver impairment, including cirrhosis. If liver injury is suspected from symptoms such as pain in the upper right abdomen, nausea, tiredness, lethargy, itching, yellow skin or eyes, flu-like symptoms or loss of appetite, it is stopped and liver tests, especially ALT, are done at once; it is not restarted after liver injury with no other cause, and periodic liver tests have not been shown to prevent serious injury. Insomnia and depression have been reported, and MedlinePlus lists other mood and behavior changes to report, such as agitation, hallucinations and suicidal behavior. In rare cases eosinophilic conditions, including vasculitis consistent with Churg-Strauss syndrome, have occurred, usually while steroid treatment was being reduced or stopped, and in trials people over 55 reported more infections than with placebo. Headache is the most common side effect; nausea, diarrhea, pain and infection also occur, and stomach pain in children.

Zafirlukast increases the effect of warfarin: the prothrombin time rises, so it is monitored closely and the warfarin dose adjusted. Erythromycin lowers zafirlukast levels, aspirin and fluconazole raise them, and rare reports describe higher theophylline levels. It passes into breast milk, and the label says it should not be given to mothers who are breastfeeding; in pregnancy it is used only if clearly needed. Accolate is still listed as a marketed brand, alongside generics rated equivalent to it.

Taking Zafirlukast

How to take it

Twice a day, at least 1 hour before or 2 hours after a meal, at about the same times each day. Keep taking it on days without symptoms, and use your quick-relief inhaler for attacks.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose. Do not take a double dose.

Storage

At room temperature, 68 to 77°F, in the original airtight container, protected from light and moisture and out of reach of children.

Interactions to know about

Warfarin’s effect increases, so prothrombin time (the INR) is checked and the dose adjusted. Erythromycin lowers zafirlukast levels, while aspirin and fluconazole raise them; rare reports describe raised theophylline levels. In laboratory studies zafirlukast slows the liver enzymes CYP2C9 and CYP3A4, so the label advises care with medicines they clear, such as phenytoin, carbamazepine and cyclosporine.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Zafirlukast differs from pharmacy to pharmacy

Generic zafirlukast is rated equivalent to Accolate and comes from several makers, so quotes for the generic differ mainly in each pharmacy’s dispensing fee and markup and in whether it keeps zafirlukast on the shelf; a pharmacy that rarely fills it may order it in and price it as a slow-moving item. A prescription written for Accolate that blocks substitution is filled at a brand price.

At one tablet twice a day a bottle of 60 lasts a month, so a longer supply once treatment is settled means fewer dispensing fees.

Ways to pay less for Zafirlukast without insurance

• Ask for generic zafirlukast, and make sure the prescription allows substitution.
• Once your asthma is stable on it, ask for a ninety-day supply.
• Confirm the pharmacy has your strength in stock before the prescription is sent, and compare more than one pharmacy.
• If it is quoted high, ask the prescriber whether another asthma controller, such as montelukast, would suit you.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Zafirlukast

1. 1.Which liver symptoms mean I should stop it and call?
2. 2.Does it change my warfarin dose or how often my INR is checked?
3. 3.How should I time my doses around meals?
4. 4.What should I use during an asthma attack?

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