Leukotriene modifiers are a class of medications designed to manage certain inflammatory conditions. These drugs work by targeting specific chemical messengers in the body known as leukotrienes. Their general purpose is to reduce inflammation and related symptoms, helping individuals with conditions where these chemical reactions play a role.
Understanding Leukotrienes
Leukotrienes are lipid molecules produced by white blood cells, including mast cells, basophils, and eosinophils. They are formed from arachidonic acid through a pathway involving the enzyme 5-lipoxygenase. These molecules act as inflammatory mediators, signaling to cells.
Their overproduction or exaggerated effects can lead to various issues. Certain leukotrienes, known as cysteinyl leukotrienes (LTC4, LTD4, and LTE4), constrict airways, increase mucus production, and promote swelling in the lungs. This excessive activity is associated with symptoms in conditions like asthma and allergic rhinitis.
How Leukotriene Modifiers Work
Leukotriene modifiers interfere with the action of leukotrienes in the body. This occurs through two main mechanisms, leading to a reduction in inflammation, a widening of the airways, and decreased mucus production.
One type, leukotriene receptor antagonists (LTRAs), blocks leukotrienes from binding to their specific receptors on target cells. Montelukast and zafirlukast are examples of LTRAs, which primarily inhibit the CysLT1 receptor, reducing inflammatory effects.
The other type, 5-lipoxygenase inhibitors, prevents the body from producing leukotrienes. Zileuton is an example, directly blocking the 5-lipoxygenase enzyme necessary for leukotriene formation. Both approaches reduce the impact of these inflammatory chemicals.
Conditions Treated by Leukotriene Modifiers
Leukotriene modifiers treat conditions with inflammation and airway issues. Their effectiveness comes from counteracting leukotriene effects.
A primary use is in the long-term management of chronic asthma, including exercise-induced bronchoconstriction. In asthma, leukotrienes cause tightening of airway muscles, increased mucus, and fluid production, making breathing difficult. By blocking these actions, leukotriene modifiers help keep bronchial tubes from constricting, reducing symptoms like wheezing, coughing, and shortness of breath.
These medications also treat allergic rhinitis, often called hay fever. Leukotrienes contribute to common allergy symptoms such as sneezing, itchy nose, and nasal congestion. Montelukast blocks allergic responses, providing relief from these symptoms.
Common Medications and Usage
Leukotriene modifier medications are prescribed as oral tablets. Montelukast (Singulair), zafirlukast (Accolate), and zileuton (Zyflo) are common examples. Montelukast treats both asthma and allergic rhinitis, while zafirlukast and zileuton are primarily for asthma.
These medications are taken daily, often as a single pill, for long-term control, not immediate relief. While some bronchodilator effects begin within hours, full anti-inflammatory benefits may take a week to a month to become noticeable. Continue taking them as prescribed, even when feeling better, as they prevent future issues. These are prescription-only medications, requiring guidance from a healthcare professional.
Potential Side Effects and Considerations
Leukotriene modifiers can have side effects. Common ones include headache, stomach pain, diarrhea, and upper respiratory infections. Some individuals may also experience fever, sore throat, or ear infections.
Montelukast carries a boxed warning regarding serious behavioral and mood-related changes. These neuropsychiatric side effects include agitation, anxiety, depression, bad dreams, irritability, and in rare instances, suicidal thoughts or actions. These events can occur in patients with or without a prior history of psychiatric conditions, and symptoms may persist even after discontinuing the medication.
Patients and caregivers should be aware of these changes and contact a healthcare professional immediately if symptoms develop. The medication should be stopped if these behavioral or mood changes are observed. For allergic rhinitis, montelukast is reserved for individuals who have not responded to or cannot tolerate other treatments.