19.4: Antiasthma Drugs: Leukotriene Modifiers

Leukotriene modifiers, or cysteinyl leukotriene receptor antagonists, are medications used to manage chronic asthma. These agents target specific inflammatory mediators produced during arachidonic acid metabolism, an essential process in generating inflammation in the body.

Leukotriene modifiers work through two distinct mechanisms:

1. 5-Lipoxygenase Inhibitors: Some drugs in this class, like zileuton (Zyflo), inhibit an enzyme called 5-lipoxygenase. This enzyme is crucial in synthesizing leukotrienes, inflammatory substances that can cause bronchoconstriction and increase lung mucus production. By inhibiting 5-lipoxygenase, zileuton prevents the formation of these inflammatory substances.
2. Leukotriene receptor antagonists (LTRAs):Other leukotriene modifiers such as zafirlukast (Accolate) and montelukast (Singulair) block the binding of specific leukotriene (leukotriene-D-4) to its receptor on the cells lining the respiratory tract. This action mitigates bronchoconstriction and inflammation, improving airflow and reducing asthma symptoms.

These medications are typically administered orally, making them easier to use than inhalation therapies. This ease of use enhances patient compliance, especially in children who struggle with inhalers or nebulizers.

While leukotriene modifiers are generally safe and well-tolerated, they can cause some adverse effects. These might include headache, nausea, abdominal pain, and cough in adults. Rarely, they may cause psychological effects such as mood changes and nightmares. If these occur, they should be reported promptly to a healthcare professional for evaluation and management.

In children, potential side effects may include nausea, diarrhea, sinusitis, and viral infections. Parents or caregivers should monitor for these symptoms and consult a healthcare provider if they arise. Despite these potential side effects, leukotriene modifiers remain a valuable tool in the arsenal of medications for managing chronic asthma.

Leukotriene modifiers, or cysteinyl leukotriene receptor antagonists, effectively manage chronic asthma by targeting inflammatory mediators produced during arachidonic acid metabolism.

These agents operate through two distinct mechanisms. Drugs like zileuton inhibit 5-lipoxygenase and prevent leukotriene synthesis. In contrast, drugs like zafirlukast and montelukast block LTD₄ binding to its receptor on respiratory mucosa, mitigating bronchoconstriction and inflammation. As a result, airflow improves, reducing asthma symptoms.

These drugs are typically administered orally, enhancing patient compliance, especially in children struggling with inhalation therapies.

Though these drugs are generally safe, potential adverse effects in adults encompass headache, nausea, abdominal pain, and cough. Rarely, psychological effects such as mood changes and nightmares may arise, necessitating prompt medical attention.

In children, symptoms like nausea, diarrhea, sinusitis, and viral infections might manifest.