6 Respiratory Pharmacotherapy: Conditions and Clinical Cases

How respiratory medicines work

Respiratory medicines have different roles: bronchodilators relax airway muscle, corticosteroids reduce inflammation, mucolytics make thick mucus easier to clear, and leukotriene modifiers reduce leukotriene-driven inflammation and bronchoconstriction. Treatment choices depend on the condition, symptom pattern, exacerbation risk, and medication safety—not just whether cough or wheeze is present.

Asthma treatment and control

Asthma treatment should include an inhaled corticosteroid (ICS). For many adults and adolescents, an ICS–formoterol inhaler is favored as a reliever. In appropriate regimens, it may be used alone as the reliever or as both maintenance and reliever therapy (MART).

A short-acting beta₂-agonist (SABA), such as albuterol, can relieve bronchospasm, but it does not treat the underlying inflammation. Using albuterol several times most days, or having symptoms that wake a person during the night, signals poor control and increased risk. The response should be reassessment and an ICS-containing treatment plan, rather than simply relying more on rescue medication.

The specific treatment regimen should be selected with a clinician. Review inhaler technique, adherence, triggers, and whether a written action plan is needed. A long-acting beta₂-agonist (LABA) should not be used alone for asthma.

Asthma inhaler combinations and ICS safety

ICS–formoterol can be used as a reliever in appropriate treatment plans, including MART. However, it should not be used as the reliever alongside maintenance ICS–LABA treatment containing a different LABA, such as salmeterol. Do not combine these regimens independently; follow the prescribed plan.

Inhaled corticosteroids can cause local effects such as oral thrush and dysphonia, or hoarseness. Rinse the mouth and spit after each dose, and review inhaler technique and device use with a clinician. Do not stop or change prescribed treatment without clinical advice.

Ongoing COPD symptom control

Long-acting bronchodilators are commonly considered for ongoing COPD symptom control. Options include a LABA, a long-acting muscarinic antagonist (LAMA), or both. A LAMA can cause dry mouth and may require caution in people with urinary retention or narrow-angle glaucoma, so inhaler selection should account for comorbidities and technique.

An ICS may be added for selected patients based on exacerbation history and other clinical factors. It is not a substitute for bronchodilation and is not routinely used by itself for COPD.

Managing COPD exacerbations

For an acute COPD exacerbation, short-acting inhaled beta₂-agonists, with or without a short-acting anticholinergic, are initial bronchodilators. A short course of systemic corticosteroids may also be used.

Antibiotics may be considered when signs suggest bacterial infection, such as newly purulent sputum, or when other guideline criteria are met. They are not automatic for every exacerbation. Severe or rapidly worsening difficulty breathing needs urgent medical assessment.

Mucolytics and persistent sputum

A prescribed mucolytic, such as carbocisteine or acetylcysteine, may be considered for selected people with COPD who have a persistent productive cough with thick sputum. It can make mucus easier to cough up, but it does not reverse acute bronchospasm, replace rescue bronchodilators, treat asthma inflammation in place of an ICS, or act as an antibiotic. Review its benefit with the prescriber.

Leukotriene modifiers and montelukast

Montelukast is a leukotriene receptor antagonist used as an add-on or alternative in selected circumstances, including for some patients with asthma and allergic rhinitis. It is not an immediate rescue medicine for a severe asthma attack and should not be assumed to replace an ICS for all patients.

Montelukast carries a boxed warning for serious neuropsychiatric events, including mood or behavior changes and suicidal thoughts. Patients and caregivers should be informed, report new concerning symptoms promptly, and discuss risks and benefits with the prescriber.

Theophylline and interaction risks

Theophylline has a narrow therapeutic range, and adverse effects and drug interactions can be important. Nausea, tremor, insomnia, or a pounding or irregular heartbeat after starting another medicine warrants prompt advice from a prescriber or pharmacist. Medication interactions and theophylline levels may need review, and blood-level monitoring may be needed.