Learning Outcomes
By the end of this section, you should be able to:
- 25.3.1 Identify the characteristics of xanthines, leukotriene modifiers, and mast cell stabilizers used to treat respiratory disorders.
- 25.3.2 Explain the indications, actions, adverse reactions, and interactions of xanthines, leukotriene modifiers, and mast cell stabilizers used to treat respiratory disorders.
- 25.3.3 Describe nursing implications of xanthines, leukotriene modifiers, and mast cell stabilizers used to treat respiratory disorders.
- 25.3.4 Explain the client education related to xanthines, leukotriene modifiers, and mast cell stabilizers used to treat respiratory disorders.
Xanthines
Xanthines are a class of drugs that have been used for many years to manage respiratory conditions, particularly asthma and COPD. Xanthines work by relaxing the smooth muscles in the airways, which helps to open the bronchial passages and improve breathing. They also have some anti-inflammatory effects and can enhance the contractility of the diaphragm.
The primary xanthine medication used in clinical practice is theophylline. Aminophylline is another xanthine that can be used to treat asthma and COPD; however, it has a very narrow therapeutic index and even with regular monitoring can lead to adverse effects.
Theophylline is typically administered orally or intravenously (Khan, 2021). It has a narrow therapeutic window, requiring careful monitoring of blood levels to ensure efficacy and prevent toxicity. The therapeutic serum levels of theophylline are 10–20 mcg/mL. Doses should be adjusted so that levels are maintained at the lowest level within this range that produces a symptomatic response (DailyMed, Theophylline, 2023). Clients with theophylline toxicity may present with abdominal pain, blurred vision, confusion, nausea, and vomiting. Although the use of xanthines has decreased with the advent of newer medications, they still play a role in certain situations and can be a valuable option for clients who do not respond well to other treatments. Clients taking theophylline should avoid other CNS stimulants such as caffeine (Cunha, 2021).
Table 25.10 lists common xanthines used for lower respiratory system disorders and typical routes and dosing for adult clients.
| Drug | Routes and Dosage Ranges |
|---|---|
| Theophylline (Theobid, Theo-24) |
Parenteral theophylline (preferred route) for acute bronchospasm in clients not currently receiving theophylline: Loading dose: 4.6 mg/kg of ideal body weight IV over 30 minutes, then maintenance infusion of 400–1600 mg/day. Adults over age 60: 0.3 mg/kg/hour IV, up to a maximum of 17 mg/hour. Oral theophylline for acute bronchospasm in clients not currently receiving theophylline: Adults age 60 and younger: 5 mg/kg orally, then 300 mg (immediate-release solution/elixir) orally daily in divided doses every 6–8 hours for 3 days. If tolerated, increase to 400 mg orally daily in divided doses every 6–8 hours. If necessary, dosage may be increased after 3 days to 600 mg orally daily in divided doses every 6–8 hours. |
| Aminophylline (Norphyl, Phyllocontin, Quibron-T) |
Loading dose: 4.6 mg/kg of ideal body weight IV over 30 minutes, then maintenance infusion of 0.4 mg/kg/hour up to a maximum of 900 mg/day unless higher doses are required to reach a target level of 10 mcg/mL. Adults over age 60: 0.3 mg/kg/hour IV, up to a maximum of 400 mg/day unless higher doses required to reach a target level of 10 mcg/mL. |
Adverse Effects and Contraindications
Close monitoring and individualized dosing are essential when utilizing xanthines in respiratory therapy. Xanthines can have a variety of potential adverse effects, including nausea, vomiting, restlessness, nervousness, increased heart rate, and tremors. The number of adverse effects is partly why xanthines are not as widely used as they formerly were. Clients with hypersensitivity, seizure disorder, hyperthyroidism, and severe cardiac arrhythmias should not use xanthines (Khan, 2021).
Table 25.11 is a drug prototype table for xanthines featuring theophylline. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
| Drug Class Xanthine Mechanism of Action Relaxes the smooth muscles located in the bronchial airways and pulmonary blood vessels |
Drug Dosage Parenteral theophylline (preferred route) for acute bronchospasm in clients not currently receiving theophylline: Loading dose: 4.6 mg/kg of ideal body weight IV over 30 minutes, then maintenance infusion of 400–1600 mg/day. Adults older than age 60: 0.3 mg/kg/hour IV, up to a maximum of 17 mg/hour. Oral theophylline for acute bronchospasm in clients not currently receiving theophylline: Adults age 60 and younger: 5 mg/kg orally, then 300 mg (immediate-release solution/elixir) orally daily in divided doses every 6–8 hours for 3 days. If tolerated, increase to 400 mg orally daily in divided doses every 6–8 hours. If necessary, dosage may be increased after 3 days to 600 mg orally daily in divided doses every 6–8 hours. |
| Indications Acute and chronic bronchospasm Therapeutic Effects Bronchodilation |
Drug Interactions Allopurinol Calcium channel blockers Macrolides Methotrexate Nicotine St. John’s wort Many others (see drug reference for full list) Food Interactions Caffeine Alcohol High-carbohydrate, low-protein diet |
| Adverse Effects Dizziness Restlessness Headache Palpitations Tachycardia Nausea Vomiting Diarrhea |
Contraindications Hypersensitivity Peptic ulcer Poorly controlled seizure disorder Caution: Older adults COPD Liver disease Diabetes |
Leukotriene Modifiers
Leukotriene modifiers, also known as leukotriene receptor antagonists or leukotriene inhibitors, are a class of medications used to manage various inflammatory conditions, particularly asthma. These medications target leukotrienes, which are inflammatory substances produced in the body in response to certain triggers. By blocking the effects of leukotrienes, leukotriene modifiers help to reduce inflammation, bronchoconstriction, and mucus production in the airways. This can lead to improved asthma control, decreased frequency of asthma symptoms, and reduced need for rescue medications.
Leukotriene modifiers, such as montelukast, zafirlukast, and zileuton, are typically administered orally and are often used as adjunctive therapy in combination with other asthma medications. Montelukast is taken at night due to its short half-life and to ensure peak drug levels with symptom onset (Cleveland Clinic, 2023b).
Table 25.12 lists common leukotriene modifiers and typical routes and dosing for adult clients.
| Drug | Routes and Dosage Ranges |
| Montelukast (Singulair) |
One 10 mg tablet orally daily, in the evening. |
| Zafirlukast (Accolate) |
One 20 mg tablet orally twice daily. |
| Zileuton (Zyflo, Zyflo CR) |
Two 600 mg tablets orally twice daily within 1 hour after morning and evening meals; total dose: 2400 mg. |
Adverse Effects and Contraindications
Montelukast is typically well tolerated; side effects include fever, headache, cough, abdominal pain, and diarrhea. Clients with hypersensitivity should not take this drug. Zafirlukast can cause headache, nausea, diarrhea, dizziness, and vomiting. Zileuton’s most common adverse effects are sinusitis and nausea. Both zafirlukast and zileuton should be avoided in clients who are hypersensitive and in clients with hepatic impairment.
Table 25.13 is a drug prototype table for leukotriene modifiers featuring montelukast. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
| Drug Class Leukotriene modifier Mechanism of Action Decreases action of leukotrienes |
Drug Dosage One 10 mg tablet orally daily, in the evening. |
| Indications Asthma Exercise-induced bronchospasm Therapeutic Effects Reduced asthmatic symptoms |
Drug Interactions Gemfibrozil Food Interactions No significant interactions |
| Adverse Effects Headaches Dizziness Epistaxis Urticaria |
Contraindications Hypersensitivity Caution: Montelukast is linked to psychological reactions such as agitation, aggression, depression, and suicidal thinking. It should be used cautiously in clients with mental health disorders and under supervision of the health care provider. |
FDA Black Box Warning
Montelukast
Serious neuropsychiatric events have been reported in clients taking montelukast. Agitation, hostile and/or aggressive behavior, depression, and suicidality have been seen.
Mast Cell Stabilizers
Mast cell stabilizers are medications used to manage allergic conditions such as asthma and allergic rhinitis. These medications work by preventing the release of inflammatory substances, particularly histamine, from mast cells. Histamine is a key mediator of allergic reactions and is responsible for the symptoms of itching, sneezing, wheezing, and swelling. By stabilizing mast cells, mast cell stabilizers help to inhibit the release of histamine and other inflammatory mediators, thereby reducing the allergic response.
Cromolyn sodium is one of the commonly used mast cell stabilizers. It is available as an inhaler for asthma and is most effective when used prophylactically, before exposure to triggers, because it does not provide immediate relief of symptoms (Science Direct, 2019).
Adverse Effects and Contraindications
Mast cell stabilizers are generally well tolerated, with minimal systemic absorption and few side effects. Side effects that may occur include coughing, sneezing, nausea, wheezing, and nasal congestion. Clients with a hypersensitivity to the drug should not take cromolyn (DailyMed, Cromolyn sodium, 2022).
Table 25.14 is a drug prototype table for mast cell stabilizers featuring cromolyn sodium (Intal). It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
| Drug Class Mast cell stabilizer Mechanism of Action Inhibits the release of mediators from mast cells Indirectly blocks calcium ions from entering the mast cell, thereby preventing mediator release |
Drug Dosage 1 ampule (20 mg/2 mL) administered by nebulization 4 times daily at regular intervals. |
| Indications Asthma symptom prophylaxis Therapeutic Effects Reduced incidence of asthmatic symptoms |
Drug Interactions No significant interactions Food Interactions No significant interactions |
| Adverse Effects Headache Diarrhea Nausea Myalgia Rash Abdominal pain |
Contraindications Hypersensitivity |
Nursing Implications
The nurse should do the following for clients who are taking xanthines, leukotriene modifiers, and mast cell stabilizers:
- Assess for hypersensitivity.
- Ensure the client’s medication list is up to date.
- Monitor for signs and symptoms of toxicity including blurred vision, nausea and vomiting, headache, and confusion.
- For leukotriene modifiers, assess for neuropsychiatric symptoms including depression, hallucinations, suicidal thoughts, and anxiety.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Client Teaching Guidelines
The client taking a xanthine, leukotriene modifier, or mast cell stabilizer should:
- Take the drug as prescribed without skipping doses or stopping therapy, even if asymptomatic.
- Report all adverse reactions including headache, diarrhea, nausea, abdominal pain, irritability, and suicidal thoughts.
- Report any worsening symptoms including shortness of breath, wheezing, or increase in allergy symptoms such as runny nose and itchy, watery eyes.
- Take drug with water and/or food to minimize GI distress.
- Keep appointments for lab draws to monitor medication levels.
The client taking a xanthine, leukotriene modifier, or mast cell stabilizer should not:
- Stop taking the drug abruptly.
- Use these medications as rescue medications in acute asthma attacks.