Monas 4 mg Chewable Tablet, produced by ACME Laboratories Ltd., is a leukotriene receptor antagonist indicated for the management of asthma, exercise-induced bronchoconstriction (EIB), and allergic rhinitis. It contains montelukast sodium, which selectively binds to cysteinyl leukotriene receptors (CysLT₁) in the airways, inhibiting the effects of leukotrienes—chemicals involved in inflammation and bronchoconstriction. By blocking these receptors, montelukast helps reduce airway inflammation, prevent bronchoconstriction, and alleviate allergy symptoms such as sneezing and nasal congestion. This medication is suitable for pediatric patients aged 2 years and older, with the 4 mg chewable tablet form being appropriate for children aged 2 to 5 years. It is typically taken once daily in the evening, with or without food, and is not intended for the relief of acute asthma attacks. Common side effects may include headache, abdominal pain, and gastrointestinal discomfort. As with any medication, it's important to follow your healthcare provider's instructions and consult them before starting or discontinuing use.