Montelukast Sandoz (Montelukast)

Montelukast acts on the leukotriene pathway to control inflammatory airway conditions.

• Asthma: improves long‑term control and reduces the frequency of exacerbations in patients with persistent asthma.
• Allergic rhinitis: alleviates nasal congestion, sneezing and itching associated with seasonal or perennial allergic rhinitis.
• Exercise‑induced bronchoconstriction: prevents airway narrowing that occurs during or after vigorous physical activity.

• Montelukast selectively antagonizes the cysteinyl leukotriene receptor CysLT1 located on airway smooth‑muscle cells, sub‑mucosal glands and inflammatory cells. By blocking the binding of leukotriene D4 and related mediators, it inhibits leukotriene‑induced bronchoconstriction, mucus secretion and vascular permeability, thereby reducing airway inflammation and hyper‑responsiveness. The effect is dose‑dependent and persists for 24 hours, allowing once‑daily dosing. It does not directly relax bronchial smooth muscle, distinguishing it from β2‑agonists.

Montelukast may cause a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Headache: mild to moderate intensity, often transient.
• Abdominal pain: discomfort in the stomach area.
• Nausea: feeling of queasiness.
• Diarrhoea: loose stools.

Serious or Rare Side Effects

• Allergic reactions: rash, angioedema or anaphylaxis requiring immediate medical attention.
• Neuropsychiatric events: mood changes, depression, suicidal thoughts or behavior.
• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.

When prescribing Montelukast, clinicians should consider several safety precautions to minimize risk.

• Assess asthma control: confirm that the patient’s asthma is stable before initiating therapy.
• Monitor neuropsychiatric symptoms: watch for mood changes, depression or suicidal thoughts during treatment.
• Use caution in hepatic impairment: adjust use if liver disease is present.
• Avoid in patients with known hypersensitivity: discontinue if allergic reaction occurs.
• Review concomitant medications: consider potential drug interactions that may affect efficacy.
• Store at room temperature: keep in the original packaging, protect from moisture and heat.

Montelukast can interact with other medicines, altering its effectiveness or safety profile.

Major Interactions (Avoid)

• Phenobarbital: strong enzyme inducer that reduces montelukast plasma concentrations.
• Rifampin: induces CYP3A4 and CYP2C9, markedly decreasing drug exposure.
• Ketoconazole: potent CYP3A4 inhibitor that may increase montelukast levels.

Moderate Interactions (Monitor Closely)

• NSAIDs: may increase risk of gastrointestinal side effects.
• Oral contraceptives: montelukast can slightly reduce hormonal efficacy.
• Other leukotriene modifiers: combined use may increase adverse effect risk.