Montelukast (Singulair) is a leukotriene receptor antagonist that is used in the maintenance treatment of asthma. It is also used to treat exercise-induced asthma and allergic rhinitis.

Indications of Montelukast (Singulair):

• Allergic rhinitis (perennial or seasonal):
  • It is prescribed to treat the signs and symptoms of both seasonal and chronic allergic rhinitis.
• Asthma:
  • It is administered to treat persistent asthma and as a preventative measure.
• Bronchoconstriction, exercise-induced (prevention):
  •  It effectively stops bronchoconstriction brought on by exercise.

Note:

• The American College of Allergy, Asthma, and Immunology (ACAAI), American Academy of Allergy, Asthma, and Surgery, and American Academy of Otolaryngology, Head & Neck Surgery (AAO-HNS) guidelines advise against using montelukast as the first-line treatment for allergic rhinitis (except in patients with concurrent asthma).
• Off Label Use of Montelukast in Adults:
  • Chronic urticaria
  • Urticaria (nonsteroidal anti-inflammatory drug-induced)

Read: Asthma Treatment Guidelines - GINA Updates Simplified

Montelukast dose in adults:

Note: Patients who suffer from allergic rhinitis as well as asthma should only take one tablet at night.

Montelukast (Singulair) Treatment dose of Allergic rhinitis (perennial or seasonal):

• Montelukast is a medicine used to treat allergy symptoms like sneezing or a runny nose.
• For adults and older kids, the usual dose is one 10 mg tablet taken by mouth once a day.

Montelukast (Singulair) dose in the treatment of Asthma:

• For treating asthma in adults and older kids, montelukast is usually taken as one 10 mg tablet by mouth in the evening.

Montelukast (Singulair) Dose in the prevention of exercise-induced bronchoconstriction:

• For preventing tightness in the chest caused by exercise, take one 10 mg montelukast tablet by mouth 2 hours before exercising.

Don't take another dose within 24 hours. If you're already taking this medicine for something else, don't take an extra dose before exercising.

Montelukast (Singulair) Dose in the treatment of Chronic urticaria:

• For treating long-lasting hives (not the usual use for this medicine), one 10 mg montelukast tablet can be taken by mouth once a day.

Montelukast (Singulair) dose in the treatment of NSAID-induced Urticaria:

• For treating hives caused by certain pain relievers (like aspirin or ibuprofen), one 10 mg montelukast tablet can be taken by mouth once a day.
• This isn't the typical use for this medicine and is based on a specific study.

Montelukast Dose in Children:

Note:Only one dose should be taken in the evening by those who have both asthma and allergic rhinitis.

Montelukast (Singulair) Dose in the Treatment of Allergic rhinitis:

For treating allergy symptoms like sneezing or a runny nose all year round:

• Babies over 6 months to kids under 6 years: one 4 mg tablet once a day.
• Kids 6 years to teens under 15 years: one 5 mg tablet once a day.
• Teens 15 years and older: one 10 mg tablet once a day.

For treating allergy symptoms during allergy season:

• Kids 2 to 5 years: one 4 mg tablet once a day.
• Kids 6 years to teens under 15 years: one 5 mg tablet once a day.
• Teens 15 years and older: one 10 mg tablet once a day.

Montelukast (Singulair) Dose in the Maintenance Treatment of Asthma:

For regular treatment of asthma:

• Kids 1 year to 5 years: one 4 mg tablet every evening.
• Kids 6 years to 14 years: one 5 mg tablet every evening.
• Teens 15 years and older: one 10 mg tablet every evening.

Montelukast (Singulair) dose in the treatment of acute exacerbation of Asthma (adjunct therapy): 

For treating a sudden asthma attack in kids:

• Kids between 2 to 5 years: Give one 4 mg tablet as a one-time dose. In a study with 52 kids having a sudden asthma attack, this 4 mg dose of montelukast, when given with another medicine called salbutamol, helped them breathe better than those who didn't get montelukast (based on Harmanci 2006 study).

Montelukast (Singulair) Dose in the prevention of Exercise-induced bronchospasm:

To prevent chest tightness caused by exercise:

• For kids 6 to 14 years: Give one 5 mg tablet 2 hours before exercise.
• For teens 15 years and older: Give one 10 mg tablet 2 hours before exercise.

Remember:

• Don't give another dose within 24 hours.
• It's not known if taking it every day just for exercise is safe.
• If someone's already taking montelukast for something else, don't give an extra dose before exercise.

Montelukast (Singulair) Dose in the treatment of NSAID-induced Urticaria: 

For treating hives caused by certain pain relievers in teens 15 years and older:

• Take one 10 mg montelukast tablet once a day.
• This advice is based on a study from 2001.

Montelukast (Singulair) Pregnancy Risk Category: B

• There's no strong evidence suggesting that montelukast harms unborn babies when taken during pregnancy
• On the other hand, not managing asthma well during pregnancy can be risky for both the mom and the baby
• This risk might be higher than any risks from taking asthma medications correctly
• So, if a pregnant woman needs montelukast for her asthma, she shouldn't avoid it just because she's pregnant.

Montelukast use during breastfeeding:

• Montelukast can be found in breast milk, but the amount that goes to the baby is relatively low (0.68% of the mother's dose)
• Usually, when this amount is under 10%, breastfeeding is considered safe
• The calculated amount of montelukast in breast milk is about 0.798 micrograms per kilogram of the baby's weight each day.
• Researchers studied 7 moms who took montelukast and breastfed their babies
• They found no bad effects in either the mothers or their babies
• The decision to breastfeed while taking montelukast should be based on the possible baby exposure, the baby's benefits from breastfeeding, and the mother's treatment benefits
• Moms with asthma are generally encouraged to breastfeed their babies.

 Montelukast (Singulair) Dose adjustment in renal disease:

No dosage adjustment necessary.

Montelukast (Singulair) Dose adjustment in liver disease:

• For patient with mild to moderate health issues, they can take the regular dose.
• For patient with serious health problems, the manufacturer doesn't give specific dosing advice because they haven't studied it in such cases.

Side Effects of Montelukast (Singulair):

• Central Nervous System:
  • Headache
  • Dizziness
  • Fatigue
• Dermatologic:
  • Atopic Dermatitis
  • Dermatitis
  • Eczema
  • Skin Infection
  • Urticaria
  • Skin Rash
• Gastrointestinal:
  • Abdominal Pain
  • Diarrhea
  • Nausea
  • Tooth Infection
  • Dyspepsia
  • Gastroenteritis
  • Toothache
• Genitourinary:
  • Pyuria
• Hepatic:
  • Increased Serum Aspartate Aminotransferase
  • Increased Serum Alanine Aminotransferase
• Infection:
  • Influenza
  • Varicella Zoster Infection
  • Viral Infection
• Neuromuscular & Skeletal:
  • Asthenia
• Ophthalmic:
  • Conjunctivitis
  • Myopia
• Otic:
  • Otalgia
  • Otitis
  • Otitis Media
• Respiratory:
  • Cough
  • Acute Bronchitis
  • Laryngitis
  • Pharyngitis
  • Pneumonia
  • Rhinitis
  • Rhinorrhea
  • Nasal Congestion
  • Epistaxis
  • Sinus Headache
  • Sinusitis
  • Upper Respiratory Tract Infection
• Miscellaneous:
  • Fever
  • Trauma

Contraindications to Montelukast (Singulair):

If someone is allergic to montelukast or any ingredient in the pill, they shouldn't take it.

Warnings and precautions

Eosinophilia, vasculitis:

• In rare situations, people might show signs of eosinophilia (a high level of certain white blood cells) and vasculitis (blood vessel inflammation) when taking montelukast
• This can sometimes look like a condition called eosinophilic granulomatosis with polyangiitis
• This condition is often treated with steroids
• Doctors should watch for symptoms like high eosinophil levels, rash, breathing problems, heart issues, and nerve problems in patients taking montelukast.

Events in neuropsychiatrics:

• There have been reports of mood and behavior changes in people taking montelukast
• These changes include unusual dreams, feeling agitated, aggressive, anxious, having trouble focusing, feeling depressed, seeing things that aren't there (hallucinations), sleeping problems, and even thoughts of suicide
• These reports have come from kids, teens, and adults
• A study by the company Merck showed that severe behavior issues were rare

Acute asthma and Bronchospasm

• Montelukast isn't officially approved for treating sudden, severe asthma attacks
• However, some research suggests it might help when used with other treatments
• Even so, people should always have their fast-acting asthma medicine ready
• If someone is having an asthma attack, they should keep taking montelukast, but also use their emergency medicine.

Aspirin-sensitive asthmatics

• Montelukast won't protect against the lung tightness caused by aspirin or similar drugs
• If someone knows they're sensitive to aspirin, they should keep avoiding it even if they're taking montelukast.

Montelukast: Drug Interaction

Monitoring parameters:

• What it is: Some people taking montelukast have reported changes in their mood or behavior.
• Symptoms to watch for:
  • Unusual dreams
  • Feeling agitated or aggressive
  • Feeling anxious or restless
  • Trouble focusing
  • Feeling very sad or depressed
  • Seeing or hearing things that aren't there (hallucinations)
  • Sleeping problems
  • Thoughts of hurting oneself or suicide
• What to do: If you or someone you know shows any of these signs after taking montelukast, contact a doctor right away.

How to administer Montelukast (Singulair)?

Asthma:

• Take the dose in the evening.

Allergic Rhinitis (allergies):

• You can choose to take it in the morning or evening, whichever works best for you.

Both Asthma and Allergies:

• Just take one dose in the evening.

Food:

• It doesn’t matter if you eat or not when taking the medicine.

Using Granules:

• You can:
  • Put them directly in the mouth.
  • Mix with a spoonful of cold or room temperature food like applesauce, carrots, rice, or ice cream.
• Don't mix with other liquids or foods.
• Once you've opened the packet, use the granules within 15 minutes.

Mechanism of action of Montelukast (Singulair):

• Montelukast is a special kind of medicine that blocks certain substances called leukotrienes.
• These leukotrienes can cause asthma problems like:
  • Swelling in the airways.
  • Tightening of the muscles around the airways.
  • Increased inflammation, which makes breathing harder.
• Leukotrienes also play a role in allergies. When you come into contact with something you're allergic to, leukotrienes are released in the nose and cause allergy symptoms.

Duration:

• Its effects last more than 24 hours.

Absorption:

• It gets into the body quickly.

Distribution:

• V: This refers to the volume in which the drug is distributed in the body. For montelukast, it's between 8 to 11 liters.

Binding:

• More than 99% of the drug attaches to proteins in the blood.

Metabolism:

• The liver breaks it down mainly using CYP3A4, 2C8, and 2C9 enzymes.

How much is available for use:

• Regular 10 mg tablet: About 64% of it.
• 5 mg chewable tablet: About 73%. If taken with a standard meal, it's 63%.

Half-life: This is how long it takes for half of the drug to be out of your system.

• Normally: 2.7 to 5.5 hours.
• If the liver isn't working perfectly: 7.4 hours.

Time to maximum effect:

• Regular 10 mg tablet: 3 to 4 hours on an empty stomach.
• 4 mg chewable tablet (for kids 2 to 5 years): 2 hours on an empty stomach.
• 5 mg chewable tablet: 2 to 2.5 hours on an empty stomach.
• Granules: 2.3 hours on an empty stomach and 6.4 hours with a high-fat meal.

Getting rid of the drug:

• 86% goes out with feces.
• Less than 0.2% goes out with urine.

International Brand Names of Montelukast:

• Singulair
• ACH-Montelukast
• AG-Montelukast
• APO-Montelukast
• Auro-Montelukast
• BIO-Montelukast
• DOM-Montelukast
• DOM-Montelukast FC
• JAMP-Montelukast
• Mar-Montelukast
• MINT-Montelukast
• MYLAN-Montelukast
• PMS-Montelukast
• PRIVA-Montelukast FC
• RAN-Montelukast
• RIVAMontelukast FC
• SANDOZ Montelukast
• Singulair
• TEVA-Montelukast
• Actamone
• Actamone FC
• Aeron
• Airfast
• Airlukast
• Altra
• Amikast
• Anxokast
• Asmaact
• Asmakast
• Asmax
• Astair
• Asthator
• Asthator 5
• Asthmatin
• Blow
• Breathezy
• Brecare
• Broncolast
• Clear Air
• Cubraxis
• Edron
• Everest
• Glemont
• Glemont-CT
• Glemont-IR
• Inmunobron
• Kast
• Kastair
• Kastair EZ
• Kipel
• Kipres
• Leukast
• Lukair
• Lukakline
• Lukast
• Lumona
• Lungair
• Mediruka
• Milukant
• Miralust
• Mokast
• Monarin
• Monas
• Monast
• Monast 10
• Monest
• Monkalus
• Monolair
• Montair
• Montecad
• Montegol
• Montek-10
• Monteka
• Montekast
• Montelair
• Montelu V
• Monteluk
• Montelukan
• Montelukan QDT
• Montemax
• Montepect
• Montexin
• Montiget
• Montulair
• Oxair
• Regulair
• Respikast
• Reversair
• Romilast
• Sansibast
• Shu Ning An
• Singkalus Chewable
• Singulair
• Singular Chew
• Sinkast
• Sintrine
• Smart-Air
• Synglon
• Tekast
• Telkast
• Unicast
• Valtrover
• Valttrover
• Vizendo

Montelukast Brand Names in Pakistan: