Montelukast

What Does Montelukast Do?

Montelukast is a leukotriene receptor antagonist (LTRA) medication, primarily used for treating and preventing asthma in both adults and children, as well as in the relief of seasonal allergies symptoms. It also has applications for exercise-induced bronchoconstriction (EIB) and off-label use in treating eosinophilic esophagitis. 

How Does Montelukast Work? (the complicated bit)

Montelukast functions as a leukotriene receptor antagonist (LTRA). Leukotrienes are substances secreted by the body in response to allergens, inducing inflammation and constriction of air passages. By obstructing leukotriene receptors, Montelukast interrupts the attachment of these substances to cells, resulting in reduced inflammation and dilatation of airways. This leads to an alleviation of allergic reactions and enhanced respiratory function.

Drug Type and Category of Montelukast

Montelukast belongs to the class of medications known as leukotriene receptor antagonists (LTRA). 

What dosage of Montelukast should you be taking?

NHS Dosage Guidelines ¹

Montelukast comes as 10mg non-chewable tablets, chewable tablets in strengths of 5mg or 4mg, and granules in sachets of 4mg.

• The usual dose for adults and children aged 15 years old and over is one 10mg tablet once a day.
• The usual dose for children aged 6 to 14 years old is one 5mg chewable tablet once a day.
• The usual dose for children from 6 months to 5 years old is 4mg once a day. This can be taken as granules, or a chewable tablet for children over 2 years old.

What are the side-effects of Montelukast?

Common Side Effects:

• Headache
• Abdominal pain
• Cough
• Dizziness
• Fatigue
• Fever (especially in children)

Less Common but Potentially Serious Side Effects:

• Mood Changes and Behavioral Side Effects: Irritability, anxiety, depression, agitation, aggressive behavior, sleep disturbances, and, in rare cases, suicidal thoughts or actions.
• Neuropsychiatric Events: Some patients have reported vivid dreams, hallucinations, and tremors.
• Allergic Reactions: Rash, itching, swelling (especially of the face, tongue, or throat), severe dizziness, and difficulty breathing.
• Liver Issues: Elevated liver enzymes, jaundice (yellowing of the skin or eyes), and liver dysfunction.

Rare Side Effects:

• Churg-Strauss Syndrome: A rare condition characterised by inflammation of blood vessels that can occur in people taking Montelukast, particularly those who are also reducing their use of oral corticosteroids.
• Increased Bleeding Tendencies: Though rare, some patients may experience increased bruising or bleeding.

Due to the potential for serious neuropsychiatric side effects, healthcare providers often monitor patients for any mood or behavioral changes, especially in children and adolescents.

Drug Interactions

Common Interactions:

Phenobarbital: This anticonvulsant and sedative may decrease the effectiveness of Montelukast by increasing its metabolism in the liver.

Rifampin: An antibiotic commonly used to treat tuberculosis, Rifampin can also decrease the levels of Montelukast in the body by inducing liver enzymes that metabolise the drug.

Gemfibrozil: This lipid-lowering medication can increase the levels of Montelukast in the blood, potentially increasing the risk of side effects.

General Considerations:

Other CYP3A4 Inducers or Inhibitors: Although Montelukast is primarily metabolised by the liver enzyme CYP2C8, it also involves CYP3A4 and CYP2C9. Therefore, drugs that strongly induce or inhibit these enzymes could theoretically affect Montelukast levels, though such interactions are not commonly reported.

Corticosteroids: No significant interaction is expected, but it's important to monitor patients who are transitioning from systemic corticosteroids to Montelukast, as this could unmask underlying conditions like Churg-Strauss syndrome.

Montelukast is not known to significantly interact with most other common medications,including antihistamines, inhaled corticosteroids, or other asthma medications.

Natural Alternatives to Montelukast ²

Natural alternatives to Montelukast can include various lifestyle changes, dietary modifications, and specific supplements. While these alternatives may help manage symptoms, they should not replace prescribed medications without consulting a healthcare provider. Vitamin C, known for its antioxidant properties, can help reduce allergy symptoms and is found in many fruits and vegetables like oranges, strawberries, and spinach. Some studies suggest that high doses may alleviate allergy-related issues. Quercetin, a flavonoid present in foods like apples and onions, has been studied for its potential to act as a natural antihistamine, with supplements possibly providing more effective doses. 

Butterbur, a plant extract often used for treating hay fever and migraines, should be used cautiously due to potential allergic reactions and liver toxicity from unprocessed forms. Probiotics can enhance gut health and may support the immune system, potentially reducing allergy symptoms. Spirulina, a blue-green algae, has shown some antihistamine effects in studies and can be consumed in supplement or powder form. Additionally, incorporating regular exercise, maintaining a healthy diet, and minimising exposure to allergens are important lifestyle changes that can help manage asthma and allergy symptoms.

Interesting facts about Montelukast

Montelukast is frequently prescribed to patients with Aspirin-Exacerbated Respiratory Disease (AERD), a condition where asthma and nasal polyps worsen after taking aspirin or other NSAIDs. It helps manage symptoms in these patients.

Montelukast has a relatively long half-life of about 2.7 to 5.5 hours, which contributes to its once-daily dosing schedule. This ensures that therapeutic levels are maintained throughout the day.

Disclaimer

This article is generated for informational purposes only. It was created in December 2024. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References

1. https://www.nhs.uk/medicines/montelukast/
2. https://www.medicalnewstoday.com/articles/323276