Please check your internet connection and try again.
# Montelukast/Levocetirizine
## Overview
A fixed-dose combination (FDC) of a leukotriene receptor antagonist (montelukast) and a second-generation H1-receptor antagonist (levocetirizine). Used primarily for allergic rhinitis with an asthma component or allergic rhinitis refractory to monotherapy. Note: Montelukast carries a significant FDA Boxed Warning.
## Primary Indications
* Allergic rhinitis (perennial and seasonal).
* Adjunctive treatment for asthma with allergic rhinitis.
## Adult Dosing
* **Standard dose:** 10 mg montelukast / 5 mg levocetirizine once daily in the evening.
## Pediatric Dosing
* **Ages 6–11 years:** 5 mg montelukast / 2.5 mg levocetirizine once daily in the evening.
* **Ages < 6 years:** Combination products are generally not recommended due to fixed-dose constraints; use individual components to titrate.
## Dose Adjustments
* **Renal Impairment:** Requires adjustment based on the levocetirizine component. In patients with CrCl 30–49 mL/min, dosing frequency may need reduction (consult specific product labeling based on local availability).
* **Hepatic Impairment:** No specific adjustment for mild-to-moderate impairment, but monitor for hepatotoxicity (montelukast association).
## Contraindications
* Hypersensitivity to montelukast, levocetirizine, or hydroxyzine/cetirizine derivatives.
* Severe renal impairment (CrCl <10 mL/min).
## Adverse Effects
* **Neuropsychiatric (Montelukast):** Agitation, aggression, depression, sleep disturbances, suicidal ideation.
* **CNS (Levocetirizine):** Somnolence (less than first-gen antihistamines, but significant in some), fatigue.
* **Other:** Upper respiratory infection, fever, headache, pharyngitis, xerostomia (dry mouth).
## Key Drug Interactions
* **CNS Depressants:** Risk of additive sedation with alcohol, opioids, or benzodiazepines.
* **CYP450 Inducers:** Phenobarbital, rifampin, and phenytoin may decrease montelukast plasma concentrations.
* **Ritonavir:** May increase plasma concentrations of levocetirizine.
## Monitoring
* **Neuropsychiatric:** Monitor for mood changes, behavior modification, or suicidal ideation. Discontinue if symptoms occur.
* **Hepatic:** Monitor for signs of hepatitis (jaundice, nausea, abdominal pain).
* **Sedation:** Advise patients to assess tolerance before driving or operating machinery.
## Clinical Pearls
* **Boxed Warning:** The FDA recommends reserving montelukast for patients who do not respond to or cannot tolerate alternative therapies due to the risk of serious neuropsychiatric events.
* **Rationale:** The combination is often used to address both the histamine-mediated phase and the inflammatory leukotriene-mediated phase of allergies/asthma.
* **Switching:** If symptoms do not improve after 2–4 weeks, reassess the treatment plan or consider monotherapy.
***
*Disclaimer: This information is for educational purposes. Clinical guidelines, particularly regarding combination products, can vary by region and local formulary. Always verify the most current prescribing information in official resources (e.g., FDA-approved labeling, BNF, or Micromedex) before prescribing or administering medication.*
