Leukotriene modifiers: Nursing pharmacology

Leukotriene modifiers are a group of medications that help breathing, so they are typically used to manage nasal congestion and inflammation associated with allergic rhinitis, as well as to manage narrowing and obstruction of the airways in obstructive lung diseases, such as asthma.

Asthma is characterized by chronic inflammation in the lungs, as well as asthma exacerbations or attacks, where certain triggers, such as viruses, allergens, stress, aspirin and exercise, lead to reversible bronchial smooth muscle spasms and mucus production, both of which make it hard to breathe. As a result, clients experience symptoms like dyspnea, wheezing, coughing, and chest tightness.

Now, leukotriene modifiers act by decreasing the action of leukotrienes, which are inflammatory molecules produced and released by certain immune cells, such as mast cells, to trigger an inflammatory response.

Once released, leukotrienes bind to leukotriene receptors located on the bronchial smooth muscles, causing them to contract, as well as on the mucous glands to increase mucus secretion. In addition, leukotrienes increase blood vessel permeability, which results in fluid leakage and edema.

Now, leukotriene modifiers can be classified into two groups, based on their mechanism of action. On the one hand, leukotriene receptor antagonists, such as montelukast and zafirlukast, bind to and block leukotriene receptors on the airways, preventing leukotrienes from binding.

On the other hand, leukotriene synthesis inhibitors, such as zileuton, inhibit the enzyme that produces leukotrienes.

Now, regardless of the exact mechanism, the net effect is decreased leukotriene action, leading in turn to decreased smooth muscle contraction in the airways, decreased mucus secretion, and decreased inflammation.

Alright, now unlike other medications that are used for asthma, leukotriene modifiers are typically administered orally and have slower onset of action, which is why they are only used as part of maintenance therapy and not during an acute attack. In addition, they are especially effective in preventing exercise- or aspirin- induced asthma.

However, leukotriene modifiers can have side effects. The most common side effects are mild and nonspecific, such as a headache, gastrointestinal disturbances, fatigue, and a skin rash or urticaria.

However, they can also lead to severe allergic reactions as well as neuropsychiatric effects like agitation, sleep disturbances, depression, and suicidal ideation.

Montelukast has a boxed warning for these neuropsychiatric events. In general, leukotriene modifiers should be used with caution in those with severe asthma, as well as in clients with existing depression or suicidal ideation.

Zafirlukast and zileuton are also potentially hepatotoxic, and zafirlukast is contraindicated in clients with active liver disease.

OK, before administering a leukotriene modifier, assess your client’s respiratory status, and confirm your client’s liver function tests are normal. Also be sure the client does not have a history of depression or suicidal ideation.