Patient leaflet - Singulair 10 mg film-coated tablets
1. WHAT SINGULAIR® IS AND WHAT IT IS USED FOR
What Singulair® is
Singulair® is a leukotriene receptor antagonist that blocks substances called leukotrienes.
How Singulair® works
Leukotrienes cause narrowing and swelling of airways in the lungs and also cause allergy symptoms. By blocking leukotrienes, Singulair® improves asthma symptoms, helps control asthma and improves seasonal allergy symptoms (also known as hay fever or seasonal allergic rhinitis).
When Singulair® should be used
Your doctor has prescribed Singulair® to treat asthma, preventing your asthma symptoms during the day and night.
- Singulair® is used for the treatment of adults and adolescents 15 years of age and older who are not adequately controlled on their medication and need additional therapy.
- Singulair® also helps prevent the narrowing of airways triggered by exercise.
- In those asthmatic patients in whom Singulair® is indicated in asthma, Singulair® can also provide symptomatic relief of seasonal allergic rhinitis.
Your doctor will determine how Singulair® should be used depending on the symptoms and severity of your asthma.
What is asthma?
Asthma is a long-term disease.
Asthma includes:
difficulty breathing because of narrowed airways.
This narrowing of airways worsens and improves in response to various conditions.
- sensitive airways that react to many things, such as cigarette smoke, pollen, cold air, or exercise.
- swelling (inflammation) in the lining of airways.
Symptoms of asthma include: Coughing, wheezing, and chest tightness.
What are seasonal allergies?
Seasonal allergies (also known as hay fever or seasonal allergic rhinitis) are an allergic response often caused by airborne pollens from trees, grasses and weeds. The symptoms of seasonal allergies typically may include: stuffy, runny, itchy nose; sneezing; watery, swollen, red, itchy eyes.
2. WHAT YOU NEED TO KNOW BEFORE YOU TAKE SINGULAIR® Tell your doctor about any medical problems or allergies you have now or have had.
Do not take Singulair®
- if you are allergic to montelukast or any of the other ingredients of this medicine (listed in section 6).
Warnings and precautions
Talk to your doctor or pharmacist before taking Singulair®.
- If your asthma or breathing gets worse, tell your doctor immediately.
- Oral Singulair® is not meant to treat acute asthma attacks. If an attack occurs, follow the instructions your doctor has given you. Always have your inhaled rescue medicine for asthma attacks with you.
- It is important that you or your child take all asthma medications prescribed by your doctor. Singulair® should not be substituted for other asthma medications your doctor has prescribed for you.
- Any patient on anti-asthma medicines should be aware that if you develop a combination of symptoms such as a flu-like illness, pins and needles or numbness of arms or legs, worsening of pulmonary symptoms, and/or rash, you should consult your doctor.
- You should not take acetyl-salicylic acid (aspirin) or anti-inflammatory medicines (also known as non-steroidal anti-inflammatory drugs or NSAIDs) if they make your asthma worse.
Patients should be aware that various neuropsychiatric events (for example behaviour and mood-related changes) have been reported in adults, adolescents and children with Singulair® (see section 4). If you develop such symptoms while taking Singulair®, you should consult your doctor.
Children and adolescents
Do not give this medicine to children less than 15 years of age. There are different form(s) of this medicine available for paediatric patients under 18 years of age based on age range.
Other medicines and Singulair®
Tell your doctor or pharmacist if you are taking or have recently taken or might take any other medicines including those obtained without a prescription.
Some medicines may affect how Singulair® works, or Singulair® may affect how other medicines work.
Tell your doctor if you are taking the following medicines before starting Singulair®:
- phenobarbital (used for treatment of epilepsy)
- phenytoin (used for treatment of epilepsy)
- rifampicin (used to treat tuberculosis and some other infections)
- gemfibrozil (used for treatment of high lipid levels in plasma)
Singulair® with food and drink
Singulair® 10 mg film-coated tablet may be taken with or without food.
Pregnancy and breast-feeding
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking Singulair®.
Pregnancy
Your doctor will assess whether you can take Singulair® during this time.
Breast-feeding
It is not known if Singulair® appears in breast milk. You should consult your doctor before taking Singulair® if you are breast-feeding or intend to breast-feed.
Driving and using machines
Singulair® is not expected to affect your ability to drive a car or operate machinery. However, individual responses to medication may vary. Certain side effects (such as dizziness and drowsiness) that have been reported with Singulair® may affect some patients’ ability to drive or operate machinery.
Singulair® 10 mg film-coated tablets contain lactose and sodium
If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product. This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
3. HOW TO TAKE SINGULAIR®
Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.
- You should take only one tablet of Singulair® once a day as prescribed by your doctor.
- It should be taken even when you have no symptoms or have an acute asthma attack.
For adults and adolescents 15 years of age and older:
The recommended dose is one 10 mg tablet to be taken daily in the evening.
If you are taking Singulair®, be sure that you do not take any other products that contain the same active ingredient, montelukast. This medicine is for oral use.
You can take Singulair® 10 mg with or without food.
If you take more Singulair® than you should
Contact your doctor immediately for advice. There were no side effects reported in the majority of overdose reports. The most frequently occurring symptoms reported with overdose in adults and children included abdominal pain, sleepiness, thirst, headache, vomiting, and hyperactivity.
If you forget to take Singulair®
Try to take Singulair® as prescribed. However, if you miss a dose, just resume the usual schedule of one tablet once daily.
Do not take a double dose to make up for a forgotten dose.
If you stop taking Singulair®
Singulair® can treat your asthma only if you continue to take it. It is important to continue taking Singulair® for as long as your doctor prescribes. It will help control your asthma.
If you have any further questions on the use of this medicine, ask your doctor or pharmacist.
4. POSSIBLE SIDE EFFECTS
Like all medicines, this medicine can cause side effects, although not everybody gets them.
In clinical studies with Singulair® 10 mg film-coated tablets, the most commonly reported side effects (may affect up to 1 in 10 people) thought to be related to Singulair® were:
- abdominal pain
- headache
These were usually mild and occurred at a greater frequency in patients treated with Singulair® than placebo (a pill containing no medication).
Serious side effects
Talk with your doctor immediately if you notice any of the following side effects, which may be serious, and for which you may need urgent medical treatment.
Uncommon: the following may affect up to 1 in 100 people
- allergic reactions including swelling of the face, lips, tongue, and/or throat which may cause difficulty in breathing or swallowing
- behaviour and mood related changes: agitation including aggressive behaviour or hostility, depression
- seizure
Rare: the following may affect up to 1 in 1,000 people
- increased bleeding tendency
- tremor
- palpitations
Very rare: the following may affect up to 1 in 10,000 people
- combination of symptoms such as flu-like illness, pins and needles or numbness of arms and legs, worsening of pulmonary symptoms and/or rash (Churg-Strauss syndrome) (see section 2)
- low blood platelet count
- behaviour and mood related changes: hallucinations, disorientation, suicidal thoughts and actions
- swelling (inflammation) of the lungs
- severe skin reactions (erythema multiforme) that may occur without warning
- inflammation of the liver (hepatitis)
Other side effects while the medicine has been on the market
Very common: the following may affect more than 1 in 10 people
- upper respiratory infection
Common: the following may affect up to 1 in 10 people
- diarrhoea, nausea, vomiting
- rash
- fever
- elevated liver enzymes
Uncommon: the following may affect up to 1 in 100 people
- behaviour and mood related changes: dream abnormalities, including nightmares, trouble sleeping, sleepwalking, irritability, feeling anxious, restlessness
- dizziness, drowsiness, pins and needles/numbness
- nosebleed
- dry mouth, indigestion
- bruising, itching, hives
- joint or muscle pain, muscle cramps
- bedwetting in children
- weakness/tiredness, feeling unwell, swelling
Rare: the following may affect up to 1 in 1,000 people
- behaviour and mood related changes: disturbance in attention, memory impairment, uncontrolled muscle movements
Very rare: the following may affect up to 1 in 10,000 people
- tender red lumps under the skin, most commonly on your shins (erythema nodosum)
- behaviour and mood related changes: obsessive-compulsive symptoms, stuttering
Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.
5. HOW TO STORE SINGULAIR®
- Keep out of the sight and reach of children.
- Do not use this medicine after the expiry date which is stated on the label after EXP. The expiry date refers to the last day of that month.
- Do not store above 30°C.
- Store in the original package in order to protect from light and moisture.
- If the tablets become discoloured or show any other signs of deterioration, you should seek the advice of your pharmacist who will tell you what to do.
- Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help to protect the environment.
6. CONTENTS OF THE PACK AND OTHER INFORMATION
What Singulair® contains
- The active substance is montelukast. Each tablet contains montelukast sodium which corresponds to 10 mg of montelukast.
The other ingredients are:
Microcrystalline cellulose, lactose monohydrate (89.3 mg), croscarmellose sodium, hyprolose (E 463), and magnesium stearate. Film coating: hypromellose, hyprolose (E 463), titanium dioxide (E 171), red and yellow ferric oxide (E 172), and carnauba wax.
What Singulair® looks like and contents of the pack
10 mg Singulair® tablets are beige, rounded square, film-coated with SINGULAIR engraved on one side, MSD 117 on the other. Blister in packages of 28 tablets.
Manufactured by Merck Sharp & Dohme B.V., Waarderweg 39, 2031 BN Haarlem, The Netherlands.
Procured from within the EU and repackaged by the Product Licence Holder Beachcourse Ltd., Unit 2-3, Townsend Industrial Estate, Waxlow Road, London, NW10 7NU.
Revision date: 23.03.2026
PL 16378/1303 POM
Singulair® is a registered trademark of N.V. Organon
Blind or partially sighted?
Is this leaflet hard to see or read? Phone Beachcourse,
Tel: 020 8896 9054 for help. Ref. number: 1303
Information is given by:
Asthma UK, 18 Mansell Street, London, E1 8AA. Alternatively phone the Asthma UK Helpline on 0300 222 5800, Monday to Friday, 9 am to 5 pm. (Asthma UK is an independent charity working to conquer asthma and is not associated with Organon Pharma (UK) Limited).