Zafir

Indications

Zafirlukast is used for the long-term prevention and control of asthma in adults and children aged 12 years and older (some products are licensed from 7 years). It helps reduce asthma attacks, wheezing and night-time symptoms. It is not a rescue medicine and does not relieve an asthma attack that has already started.

How It Works

Zafirlukast is a leukotriene receptor antagonist. Leukotrienes are natural chemicals released in the airways that cause swelling, mucus and tightening of the airway muscles. By blocking their receptors, Zafirlukast keeps the airways more open and less inflamed.

Dosage and Administration

Adults and children 12 years and older: usually 20 mg twice a day. Take it on an empty stomach, at least 1 hour before or 2 hours after meals, because food reduces absorption. Take it every day, even when you feel well. Children under 12 years: only as prescribed. Keep using your reliever inhaler for sudden symptoms and do not stop inhaled steroids unless your doctor tells you to.

Interactions

Zafirlukast can increase the effect of Warfarin, so blood clotting tests (INR) need closer checking. Aspirin may raise its blood level, while Erythromycin and Theophylline may lower it. It can also affect other medicines processed by liver enzymes, such as some calcium channel blockers and Phenytoin. Tell your doctor about all medicines you take.

Contraindications

Do not use if you are allergic to Zafirlukast or any ingredient, or if you have liver disease or liver impairment, including cirrhosis.

Side Effects

Headache and stomach upset are the most common. Others include nausea, diarrhoea, sore throat, muscle aches, rash and mild infections. Rarely, it may cause liver inflammation, or a condition called Churg-Strauss syndrome (inflammation of blood vessels), especially when oral steroid doses are being reduced. Mood or sleep changes have been reported.

Get urgent medical help if you notice yellowing of the skin or eyes, dark urine, pain in the upper right side of the abdomen, severe tiredness or loss of appetite, a rash with tingling or numbness in the arms or legs, worsening breathing, or swelling of the face or throat.

Pregnancy and Lactation

There is limited information on use in pregnancy; use only if your doctor advises it. Zafirlukast passes into breast milk, so it is generally not recommended while breastfeeding.

Precautions and Warnings

Your doctor may check your liver function. Stop taking it and see a doctor at once if signs of liver problems appear. Tell your doctor about any change in mood, behaviour or sleep. Older people may have more infections while using it. Do not use it to treat a sudden attack.

Overdose

Limited information is available. An overdose may cause rash or stomach upset. Seek medical advice; treatment is supportive.

Therapeutic Class

Anti-asthma medicine, leukotriene receptor antagonist.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.