Respiratory therapy drugs are strictly used to only target the lungs and airways. To avoid unnecessary side effects, drugs targeting the respiratory system are inhaled instead of being directly injected into the bloodstream through IV, or orally by a pill. Many different pharmacological agents are used in respiratory care, but I will concentrate on the ones used most often- bronchodilators, mucolytics, and corticosteroids.
Bronchodilators are the most frequently inhaled medications for treating COPD and asthma1. They are divided into two groups; adrenergic (sympathomimetic) and anticholinergic (parasympatholytic), as well as short or long acting. The adrenergic bronchodilators stimulate the sympathetic nervous system and cause bronchodilation, while anticholinergic bronchodilators cause dilation by blocking the receptor for acetylcholine, the neurotransmitter in the parasympathetic nervous system. Short acting drugs have a duration of approximately 4-6 hours, whereas long-acting drugs last about 12 hours. The onset of action for long-acting drugs is longer than 20 minutes with peak flow improvement in about 3-4 hours; therefore it would not be used for an immediate relief.
Short-acting adrenergic bronchodilators such as albuterol and levalbuterol are indicated for relief of acute reversible airflow obstruction in an obstructive disease such as asthma2. For maintenance of bronchodilation and daily control of bronchospasm, a patient with COPD would inhale long-acting agents such as salmeterol, formoterol, and arfomortelor2. Epinephrine, an-ultra short-acting catecholamine (a sub-class of adrenergic bronchodilators) may also be used to relax the airway smooth muscles. Anticholinergic bronchodilators are another way of producing airway relaxation and relief from shortness of breath. A peak flow meter is used to monitor the peak expiratory flow (PEF) before and after bronchodilator therapy to gauge the effectiveness of the therapy.
N-acetyl-cysteine (NAC) and dornase alfa are considered mucolytics and are used to reduce mucous viscosity and improve mucociliary clearance. Mucoactive drug therapy can be used with aerosol nebulizers and its effectiveness is assessed by the patient’s airflow changes and FEV1, breathing pattern, rate, and subjective reaction. Indication of mucous controlling agents would include patients with diseases such as COPD, acute tracheobronchitis, and bronchiectasis. Another way we use NAC daily would be to treat or prevent liver damage that can occur when a patient takes an overdose of acetaminophen. NAC can be very irritable to the airways and can produce bronchospasm. It is recommended to use 10% rather than 20% solution and pre-treat with a bronchodilator to reduce the appearance of bronchospasm.
Inhaled glucocorticoids/corticosteroids are used for patients with asthma and severe COPD. Corticosteroids are different from bronchodilators mainly because they are controller agents and do not provide immediate relief; full anti-inflammatory effects require hours to days to be felt by the patient2.
Respiratory therapists use many more drugs and inhalers to administer therapy. Aerosol therapy has many modes of action and therapy is selected depending on the patient’s needs. Every drug class has different side effects that should be looked at closely to make sure the patient is benefiting from the therapy.
- Prescribing inhaled bronchodilators and inhaler devices.(2015). Nurse Prescribing, 13(9), 438-445 6p.
- Kacmrek, R. M., Stroller, J. K., & Heuer, A. J. (2013). History of respiratory care. In Robert Kacmrek, James Stroller, Albert Heuer (Ed.). United States: Elsevier Inc.
Respiratory Care 