Usage
Bilastine + Montelukast is prescribed for the treatment of allergic rhinitis (hay fever) and asthma. It is also sometimes used to manage refractory and non-responsive urticaria (hives). It belongs to the pharmacological classifications of antihistamines (bilastine) and leukotriene receptor antagonists (montelukast). This fixed-dose combination therapy addresses both the early and late phases of allergic responses. Bilastine works by blocking the action of histamine, a chemical released during allergic reactions. Montelukast inhibits leukotrienes, which contribute to inflammation and bronchoconstriction.
Alternate Names
There are no widely recognized alternate names for the combination itself. However, it’s marketed under various brand names such as Bilafast-M, Bilaset M, Montek BL, Bilazest M, Bilazap M, Odastin M, Bilacad M, Bilahenz M, Prulastin M, Bilagra M, Billasi M, Bilanta M, Bilachek M, Antegy M, Bilafav M, Bilamed M, and Belatin M. It is also sometimes known as AllerDuo.
How It Works
Pharmacodynamics: Bilastine is a selective histamine H1-receptor antagonist that doesn’t readily cross the blood-brain barrier, leading to fewer central nervous system side effects like drowsiness. Montelukast is a leukotriene receptor antagonist, specifically CysLT1. It blocks the binding of leukotrienes, preventing airway constriction and inflammation.
Pharmacokinetics: Bilastine is well-absorbed orally and metabolized primarily through hepatic glucuronidation, with a smaller amount undergoing CYP3A4 metabolism. It is excreted mainly in feces and to a lesser extent in urine. Montelukast is also well-absorbed orally, extensively metabolized by CYP2C8 and CYP3A4, and primarily eliminated through the biliary route with minimal renal excretion.
Mode of Action: Bilastine competitively inhibits histamine binding to H1 receptors, reducing allergic symptoms. Montelukast blocks the CysLT1 receptor, inhibiting the effects of leukotrienes which include bronchoconstriction, mucus secretion, and eosinophil recruitment, thereby reducing inflammation.
Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: Bilastine binds to H1 histamine receptors. Montelukast binds to and antagonizes CysLT1 receptors. The combination does not significantly modulate neurotransmitters or inhibit enzymes other than CYP metabolism mentioned previously.
Elimination Pathways: Bilastine is excreted primarily in feces through hepatic glucuronidation and some CYP3A4 metabolism. Montelukast is excreted primarily through bile after metabolism by CYP2C8 and CYP3A4.
Dosage
Standard Dosage
Adults:
The standard dose is one tablet containing 20mg bilastine and 10mg montelukast taken orally once daily, with or without food.
Children:
- For children aged 6-11 years weighing at least 20kg: A formulation containing bilastine 10mg + montelukast 4mg per 5ml suspension is available, with the dosage determined by the physician.
- The combination is not recommended for children under 6 years of age.
Special Cases:
- Elderly Patients: No specific dose adjustments are typically required.
- Patients with Renal Impairment: Use with caution. Dose adjustment may be needed.
- Patients with Hepatic Dysfunction: Use with caution. Dose adjustment may be needed.
- Patients with Comorbid Conditions: Consider interactions with other medications.
Clinical Use Cases
Specific dosing guidelines for clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations are not established for this combination.
Dosage Adjustments:
Adjustments might be necessary for patients with renal or hepatic impairment, although no standardized guidelines exist. Dosage is determined on a case-by-case basis. Genetic polymorphisms affecting CYP2C8 and CYP3A4 might impact the pharmacokinetics, but the clinical significance is not fully understood.
Side Effects
Common Side Effects:
Headache, drowsiness, fatigue, upper respiratory tract infection, fever, pharyngitis, cough, abdominal pain, diarrhea, influenza, rhinorrhea, sinusitis, nausea, vomiting, dry mouth.
Rare but Serious Side Effects:
Neuropsychiatric events (e.g., mood changes, depression, suicidal thoughts, aggressive behavior), Churg-Strauss syndrome (systemic eosinophilia with vasculitis), allergic reactions (including skin rash, itching, angioedema).
Long-Term Effects:
No specific long-term effects have been definitively identified for this combination specifically.
Adverse Drug Reactions (ADR):
Any of the rare but serious side effects could be considered an ADR, particularly neuropsychiatric events or Churg-Strauss syndrome.
Contraindications
Hypersensitivity to bilastine or montelukast.
Drug Interactions
The combination can interact with:
- CYP3A4 and CYP2C8 inhibitors/inducers: Ketoconazole, erythromycin, rifampicin, phenytoin, phenobarbital.
- Other Medications: Gemfibrozil, itraconazole, some HIV protease inhibitors, antacids containing magnesium or aluminum, H2 receptor antagonists.
- Food and Lifestyle Factors: Grapefruit juice and other fruit juices may decrease the effectiveness of bilastine. Alcohol may increase drowsiness.
Pregnancy and Breastfeeding
The safety of this combination during pregnancy and breastfeeding has not been fully established. It’s recommended to consult with a healthcare provider to weigh the potential risks and benefits.
Drug Profile Summary
- Mechanism of Action: Bilastine: H1 receptor antagonist; Montelukast: CysLT1 receptor antagonist.
- Side Effects: Headache, drowsiness, gastrointestinal disturbances, neuropsychiatric events (rare).
- Contraindications: Hypersensitivity.
- Drug Interactions: CYP3A4/2C8 inhibitors/inducers, some antibiotics, antifungals, antacids.
- Pregnancy & Breastfeeding: Limited data; use with caution.
- Dosage: Adults: Bilastine 20mg/Montelukast 10mg once daily. Pediatric dosage varies.
- Monitoring Parameters: Monitor for allergic reactions and neuropsychiatric effects.
Popular Combinations
This combination itself is a popular pairing in clinical practice. It can be used concomitantly with other medications for allergy and asthma management, such as inhaled corticosteroids, but under the supervision of a physician.
Precautions
Screen for allergies to bilastine and montelukast, liver or kidney impairment. Exercise caution during pregnancy, while breastfeeding, and in children and the elderly. Advise patients against driving or operating machinery if drowsiness occurs.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Bilastine + Montelukast?
A: For adults, the standard dose is one tablet containing 20mg bilastine and 10mg montelukast taken orally once daily. For children aged 6-11 years weighing at least 20kg, a formulation containing 10mg bilastine + 4mg montelukast per 5ml is available, with the dosage determined by the physician.
Q2: What are the primary uses of Bilastine + Montelukast?
A: It’s mainly used to treat allergic rhinitis and asthma.
Q3: How should this combination be administered?
A: Orally, with or without food. Do not crush or chew the tablets. Swallow whole with water.
Q4: Are there any significant drug interactions with Bilastine + Montelukast?
A: Yes, with some antifungals (ketoconazole), antibiotics (erythromycin), anticonvulsants (phenytoin, phenobarbital), and other drugs metabolized by CYP3A4 or CYP2C8. Antacids and fruit juices may decrease absorption.
Q5: What are the common side effects patients should be aware of?
A: Headache, dry mouth, drowsiness, gastrointestinal issues, and flu-like symptoms are common.
Q6: Can Bilastine + Montelukast be used during pregnancy or breastfeeding?
A: Consult with a healthcare professional to assess potential risks and benefits before use during pregnancy or breastfeeding.
Q7: Is this combination safe for children?
A: A specific formulation is available for children between 6 and 11, but it is generally not recommended for children under 6.
Q8: What should patients do if they experience side effects?
A: Report any persistent or severe side effects to their physician.
Q9: What is the role of each component in this combined medication?
A: Bilastine is an antihistamine, reducing allergic symptoms. Montelukast is a leukotriene antagonist, managing asthma and allergic inflammation.
Q10: Why is this combination prescribed together?
A: The combination provides a synergistic approach, addressing both immediate allergic reactions and underlying inflammation, offering broader relief.
