Montekulast: spelling variant of the leukotriene antagonist montelukast
Montekulast is a common spelling variant of the correct substance name montelukast. Confusion arises from the similar-sounding syllables k and t in Singulair (US brand name) and the ending kast. Pharmacologically the same substance is meant in both cases: an oral leukotriene receptor antagonist for the treatment of bronchial asthma, allergic rhinitis and prevention of exercise-induced asthma.
Montelukast was approved in the USA in 1998 and shortly thereafter in the EU. It is taken orally once daily and has very good patient acceptance, especially in children, since chewable and lozenge tablets are available.
Mechanism of action
Cysteinyl leukotrienes (LTC4, LTD4, LTE4) are inflammatory mediators formed from arachidonic acid via the 5 lipoxygenase cascade. They are released mainly from mast cells, eosinophils and macrophages and are central mediators of allergic inflammation. At CysLT1 receptors on bronchial muscle and airway endothelium they induce:
- Bronchoconstriction
- Mucus secretion and mucosal oedema
- Eosinophil recruitment
- Vascular permeability
Montelukast binds selectively and competitively to the CysLT1 receptor, blocks leukotriene binding and interrupts downstream effects. Unlike inhaled corticosteroids, montelukast does not have a broad anti-inflammatory effect but acts selectively on the leukotriene axis.
Oral bioavailability is about 64 %, action begins within hours, full clinical effect develops over several days.
Indications
- Bronchial asthma: as add-on to inhaled corticosteroids when symptom control is insufficient, or as alternative in mild persistent asthma
- Exercise-induced bronchoconstriction: prevention before physical activity
- Allergic rhinitis: seasonal and perennial, especially in patients with asthma comorbidity
- Aspirin-sensitive asthma (Samter's triad): off-label, since aspirin enhances leukotriene production
Montelukast is not suitable for acute asthma attacks. For acute breathlessness short-acting beta-2 agonists are used.
Dosing and administration
Adults and adolescents from 15 years: 10 mg once daily in the evening.
Children 6 to 14 years: 5 mg chewable tablet once daily in the evening.
Children 2 to 5 years: 4 mg chewable tablet or granules once daily in the evening.
Children 6 months to 5 years: 4 mg granules once daily in the evening, in water or soft food.
Evening dosing matches the daily variation of leukotriene production and asthma symptoms. For exercise-induced asthma as on-demand use, take 2 hours before sport.
Take regardless of meals. Granules should be taken within 15 minutes of opening the sachet; once mixed do not use later.
Side effects
Common: headache, abdominal pain, gastrointestinal complaints, dizziness, fatigue, sleep disturbances, rash.
Uncommon: nightmares, irritability, anxiety, depressive mood, aggression, concentration problems, tinnitus, tremor, tachycardia, pruritus, urticaria.
Rare and very rare: suicidal thoughts and behavioural changes (especially in children and adolescents), anaphylaxis, hepatitis, cholestasis, pancreatitis, Churg-Strauss syndrome, Stevens Johnson syndrome, angioedema.
Important safety information (FDA boxed warning since 2020):
- Neuropsychiatric side effects including suicidal thoughts can occur with montelukast
- Before starting therapy, benefit and risk should be carefully weighed
- Patients and relatives should be informed about possible mood and behavioural changes
- If new psychiatric symptoms appear, pause or stop therapy
- In children, inform parents closely and watch for behavioural changes
Churg-Strauss syndrome: rare, often in connection with reduction of systemic steroid therapy under ongoing montelukast use. Eosinophilia, vasculitis, asthma worsening, mononeuritis as warning signs.
Interactions
- Strong CYP3A4 and CYP2C8 inducers (rifampicin, phenobarbital, phenytoin, carbamazepine): reduced levels, avoid combination if possible
- Strong CYP3A4 inhibitors (itraconazole, ketoconazole, clarithromycin): level increase possible
- Gemfibrozil: CYP2C8 inhibition, marked level increase possible
- Other asthma drugs: sensible combinations with ICS, LABA and SABA
- Warfarin: isolated reports of INR change, monitoring sensible
Special considerations
Pregnancy: limited data. If clinically required, individual judgement. With stable asthma on ICS, montelukast should not be added without a clear indication.
Breastfeeding: small passage into milk, usually clinically tolerable.
Children and adolescents: review the indication strictly, especially in children with prior psychiatric conditions or family behavioural concerns. Parents should know about neuropsychiatric warnings.
Older patients: no dose adjustment required, well tolerated.
Renal and hepatic impairment: no adjustment in mild to moderate impairment. With severe hepatic impairment, caution and possible dose reduction.
Patients with aspirin-sensitive airway disease: montelukast can be helpful, especially with nasal polyps and asthma. Aspirin should still be consistently avoided, since leukotriene antagonism reduces but does not eliminate symptoms.
Therapy monitoring: check asthma symptoms and lung function regularly. With insufficient effect, do not escalate therapy but reassess whether the diagnosis is correct and whether the ICS component is adequate.
Related substances
- Montelukast, correct spelling of the substance
- Dupilumab, biologic in severe asthma
- Fluticasone, ICS in asthma and COPD
- Aclidinium, LAMA in COPD
- Umeclidinium, once-daily LAMA
Frequently asked questions
Is the substance called montekulast or montelukast?
The correct name is montelukast. Montekulast is a common spelling variant, presumably due to mispronunciation or typing error. Both terms refer to the same substance.
Does montelukast replace inhaled corticosteroids?
In most cases no. Inhaled corticosteroids remain the basic therapy in persistent asthma because they target the underlying inflammation more broadly and powerfully. Montelukast is often used as add-on with insufficient control or in specific subgroups, such as exercise-induced asthma or allergic rhinitis comorbidity.
Should I avoid montelukast because of psychiatric side effects?
Most patients tolerate montelukast well. However, neuropsychiatric side effects such as nightmares, irritability, depressive mood and rarely suicidality are known, especially in children and adolescents. The topic should be discussed openly before starting. With prior psychiatric conditions or family burden, careful weighing is sensible.
When should montelukast be taken?
In the evening, ideally at the same time. Evening dosing matches the daily rhythm of leukotriene production and supports night-time and morning symptom control. For exercise-induced asthma an additional dose can be taken 2 hours before sport.
Sources
- EMA European Medicines Agency
- BfArM Federal Institute for Drugs and Medical Devices
- AWMF S3 asthma and allergic rhinitis guideline
- Gelbe Liste montelukast monograph
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