Montelukast

# Montelukast ## Overview - **Classification**: Leukotriene Receptor Antagonist (LTRA) - **Mechanism**: Selectively blocks the CysLT1 receptor, inhibiting the actions of leukotrienes involved in inflammation in asthma and allergic rhinitis. ## Primary Indications 1. **Asthma Prophylaxis & Chronic Treatment**: For patients ≥12 months old. 2. **Exercise-Induced Bronchoconstriction (EIB) Prevention**: For patients ≥6 years old. 3. **Allergic Rhinitis (Seasonal & Perennial)**: For patients ≥6 months old. ## Adult Dosing ### Standard Dosing **Asthma / Allergic Rhinitis / EIB Prevention** - **Dose**: **10 mg** - **Frequency**: Once daily - **Route**: Oral - **Special Considerations**: For asthma/AR, take in the evening. For EIB, take at least 2 hours before exercise; do not take an additional dose if already taking daily montelukast. ### Dose Adjustments - **Renal Impairment**: No dose adjustment needed. - **Hepatic Impairment**: No dose adjustment needed for mild-to-moderate impairment. Not studied in severe. - **Elderly Patients**: No dose adjustment needed. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: Not indicated. - **Special Notes**: Safety and efficacy not established in this age group. ### Infants (1-12 months) **Allergic Rhinitis (6 months to 5 years)** - **Dose**: **4 mg** (oral granules or chewable tablet) - **Frequency**: Once daily, in the evening - **Maximum**: **4 mg/day** - **Special Notes**: For seasonal and perennial allergic rhinitis. Oral granules can be mixed with soft food or formula; administer within 15 minutes. ### Children (1-12 years) **Asthma / Allergic Rhinitis (12 months to 5 years)** - **Dose**: **4 mg** (oral granules or chewable tablet) - **Frequency**: Once daily, in the evening - **Maximum**: **4 mg/day** - **Special Notes**: For asthma and allergic rhinitis. **Asthma / Allergic Rhinitis (6-14 years)** - **Dose**: **5 mg** (chewable tablet) - **Frequency**: Once daily, in the evening - **Maximum**: **5 mg/day** **EIB Prevention (6-14 years)** - **Dose**: **5 mg** (chewable tablet) - **Frequency**: At least 2 hours before exercise - **Maximum**: **1 dose/24h**. Do not take an additional dose if already on daily montelukast for asthma/AR. ### Adolescents (13-18 years) **Asthma / Allergic Rhinitis / EIB Prevention (≥15 years)** - **Dose**: **10 mg** (tablet) - **Frequency**: Once daily, in the evening (for asthma/AR) or 2 hours prior to exercise (for EIB). - **Maximum**: **10 mg/day** - **Special Notes**: Follow adult dosing guidelines. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to montelukast or any component. - **Absolute**: Acute asthma attacks, including status asthmaticus (not for rescue use). ### Common Adverse Effects - **Very Common (>10%)**: Upper respiratory infection (pediatric). - **Common (1-10%)**: Headache, abdominal pain, cough, diarrhea, flu-like symptoms, dizziness, fatigue, rash, pharyngitis, nausea, dyspepsia, otitis media (pediatric). - **Serious but Rare**: Neuropsychiatric events (agitation, aggression, depression, suicidal thoughts/behavior, tremor, sleep disturbance), Churg-Strauss Syndrome (eosinophilic conditions). ### Key Drug Interactions - **Phenobarbital, Rifampin**: May decrease montelukast plasma levels. Clinical monitoring advised; no dose adjustment usually needed. - **No significant interactions** with commonly co-administered asthma medications. ## Monitoring & Follow-up - **Before Treatment**: Assess baseline asthma/allergic rhinitis symptom control. - **During Treatment**: Monitor for improvement in asthma symptoms, reduction in rescue inhaler use. - **During Treatment**: Monitor for improvement in allergic rhinitis symptoms. - **During Treatment**: Closely monitor for neuropsychiatric symptoms (e.g., agitation, depression, suicidal ideation) in all patients, especially children and adolescents. - **Clinical Signs**: Watch for worsening asthma, new onset neuropsychiatric symptoms, or signs of eosinophilic conditions. ## Clinical Pearls - 💡 **Tip 1**: Administer montelukast once daily in the evening for optimal efficacy in asthma and allergic rhinitis. - 💡 **Tip 2**: For EIB prevention, take at least **2 hours before exercise**. Do not take an additional dose if already on daily montelukast for other indications. - 💡 **Tip 3**: Counsel patients and caregivers about potential neuropsychiatric side effects, including mood changes, aggression, and suicidal thoughts. Report any changes promptly. - 💡 **Tip 4**: Montelukast is not for the relief of acute asthma attacks; patients should always have a short-acting beta-agonist (SABA) available. - 💡 **Tip 5**: Oral granules can be mixed with a spoonful of soft food (e.g., applesauce, pureed carrots, rice, ice cream) or 5-10 mL of breast milk/formula and administered immediately (within 15 minutes). > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.