Usage
Levocetirizine + Montelukast is prescribed for the relief of symptoms associated with allergic rhinitis (both seasonal and perennial) and for the treatment of comorbid asthma and allergic rhinitis. It offers a synergistic effect, targeting both the histamine and leukotriene pathways involved in allergic inflammation. It is also used as prophylaxis in seasonal allergic rhinitis.
Its pharmacological classifications include:
- Levocetirizine: Antihistamine (second-generation).
- Montelukast: Leukotriene receptor antagonist.
Mechanism of Action: Levocetirizine competitively binds to peripheral H1 receptors, inhibiting histamine-mediated responses like vasodilation, capillary permeability, and bronchoconstriction. Montelukast selectively antagonizes the cysteinyl leukotriene receptor CysLT1, blocking the effects of leukotrienes which are potent bronchoconstrictors and pro-inflammatory mediators.
Alternate Names
While no official alternate names exist for the combination itself, the individual components have various names. Levocetirizine is the active enantiomer of cetirizine and is sometimes referred to as such. Montelukast sodium is the sodium salt form of montelukast. Brand names vary depending on the manufacturer and region but can include names like Larkast, Glemont L, and Co-Altria.
How It Works
Pharmacodynamics: Levocetirizine reduces vascular permeability, itching, and smooth muscle contraction associated with allergic responses. Montelukast inhibits bronchoconstriction, mucus secretion, and eosinophil recruitment in the airways.
Pharmacokinetics:
- Absorption: Both drugs are rapidly absorbed after oral administration.
- Metabolism: Levocetirizine undergoes minimal hepatic metabolism. Montelukast is primarily metabolized by CYP3A4 and CYP2C9 enzymes.
- Elimination: Levocetirizine is primarily excreted unchanged in urine. Montelukast and its metabolites are primarily eliminated in bile.
Mode of Action: Levocetirizine exerts its action by selectively blocking peripheral H1 receptors. Montelukast selectively and competitively inhibits the binding of LTD4 to the CysLT1 receptor, thus reducing the bronchoconstriction, mucus secretion, and airway edema.
Dosage
Standard Dosage
Adults: One tablet containing Levocetirizine 5mg + Montelukast 10mg once daily, usually taken in the evening.
- 2-5 years: One chewable tablet containing Montelukast 4mg and Levocetirizine 2.5 mg once daily.
- 6-14 years: One chewable tablet containing Montelukast 5mg and Levocetirizine 5mg once daily.
Special Cases:
- Elderly Patients: Dosage adjustments may be necessary based on renal function.
- Patients with Renal Impairment: Dosage adjustments of levocetirizine are necessary. For mild renal impairment (CrCl 50-80 mL/min), use Levocetirizine 2.5mg + Montelukast 10mg once daily. For moderate renal impairment (CrCl 30-50 mL/min), use the same dosage every other day.
- Patients with Hepatic Dysfunction: Caution is advised for patients with hepatic impairment, especially in severe cases. Dosage adjustment of montelukast may be necessary.
- Patients with Comorbid Conditions: Consider individual patient factors and potential drug interactions.
Clinical Use Cases
This combination isn’t typically used in the acute management of conditions like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its role is primarily in the chronic management of allergic rhinitis and asthma.
Dosage Adjustments
Dosage adjustments are necessary for patients with renal or hepatic impairment. Consult specific guidelines based on the degree of impairment.
Side Effects
Common Side Effects
Headache, drowsiness, dry mouth, fatigue, nausea, diarrhea, skin rash, pharyngitis, cough, abdominal pain, and epistaxis. In younger children, pyrexia, vomiting, diarrhea, and otitis media have been reported.
Rare but Serious Side Effects
Hepatotoxicity, neuropsychiatric events (e.g., agitation, aggression, hallucinations, depression, suicidal ideation), Churg-Strauss Syndrome (rare systemic vasculitis).
Long-Term Effects
Chronic complications are rare but careful monitoring is necessary, especially regarding neuropsychiatric events.
Adverse Drug Reactions (ADR)
Severe hypersensitivity reactions (angioedema, anaphylaxis), severe neuropsychiatric events require immediate attention.
Contraindications
Hypersensitivity to levocetirizine, montelukast, or any component of the formulation. Severe renal impairment (CrCl <10 mL/min). Patients with galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption. Pregnancy. Breastfeeding.
Drug Interactions
Clinically significant interactions are rare but can occur with:
- CYP450 inducers (e.g., phenobarbital, rifampin): May decrease montelukast levels.
- CYP450 inhibitors (e.g., ritonavir): May increase levocetirizine levels.
- Theophylline: Montelukast may affect theophylline levels.
- Other CNS depressants: May enhance sedative effects.
- Alcohol: May increase drowsiness.
Pregnancy and Breastfeeding
Contraindicated in pregnancy and breastfeeding. Levocetirizine is excreted in breast milk, and the safety of montelukast during breastfeeding is not fully established.
Drug Profile Summary
- Mechanism of Action: Levocetirizine: H1 receptor antagonist. Montelukast: CysLT1 receptor antagonist.
- Side Effects: Headache, drowsiness, dry mouth, fatigue, nausea, diarrhea.
- Contraindications: Hypersensitivity, severe renal impairment, pregnancy, breastfeeding.
- Drug Interactions: CYP450 inducers/inhibitors, theophylline, CNS depressants.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Adults: Levocetirizine 5mg + Montelukast 10mg once daily. Pediatric dosing varies with age.
- Monitoring Parameters: Liver function tests, renal function tests, monitor for neuropsychiatric symptoms.
Popular Combinations
Often used as a standalone combination. However, it may be prescribed along with intranasal corticosteroids for more severe allergic rhinitis or asthma.
Precautions
- General Precautions: Monitor for adverse effects, especially neuropsychiatric symptoms. Assess renal and hepatic function.
- Specific Populations: Use with caution in the elderly and in patients with hepatic impairment.
- Lifestyle Considerations: Avoid alcohol. Avoid driving or operating machinery if drowsiness occurs.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Levocetirizine + Montelukast?
A: Adults: Levocetirizine 5mg + Montelukast 10mg once daily. Pediatric dosing varies with age.
Q2: Can this combination be used during pregnancy or breastfeeding?
A: No, it is contraindicated.
Q3: How does this combination work?
A: Levocetirizine blocks histamine, while montelukast blocks leukotrienes, both of which are involved in allergic reactions.
Q4: What are the common side effects?
A: Headache, drowsiness, dry mouth, fatigue, nausea, diarrhea.
Q5: Are there any serious side effects I should be aware of?
A: Yes, though rare, neuropsychiatric events and hepatotoxicity are possible. Patients should be monitored accordingly.
Q6: What should I do if my patient experiences side effects?
A: Most side effects are mild and transient. If they persist or are severe, discontinue the medication and contact a healthcare professional.
Q7: Does this medication interact with other drugs?
A: It can interact with some medications, including certain antibiotics, antifungals, and those metabolized by CYP3A4 and CYP2C9 enzymes.
Q8: Can it be used in patients with renal or hepatic impairment?
A: Caution is advised. Dosage adjustments may be necessary for renal impairment. It should be avoided in severe hepatic impairment.
Q9: How long should a patient take this medication?
A: The duration of treatment depends on the individual patient and the condition being treated. It’s generally prescribed for as long as allergy symptoms persist.
Q10: Can I prescribe this to a patient with epilepsy?
A: Caution is advised. Montelukast has been associated with neuropsychiatric events, and close monitoring is essential. Consult specialist advice.
