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Chapter 32
Airway Pharmacology
Objectives
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Analyze three phases that constitute the course of drug action from
dose to effect.
Describe classes of drugs that are delivered via the aerosol route.
Compare mode of action, indications, and adverse effects that
characterize each major class of aerosolized drug.
Compare available aerosol formulations, brand names, and dosages
for each specific drug class.
Select the appropriate drug class for a given patient or clinical situation.
Assess the outcomes for each class of aerosol drug therapy.
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Principles of Pharmacology
The drug administration phase

The method by which a drug is made available to the body
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Aerosol therapy is the most common route for drug
administration to the pulmonary patient.
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The most common devices used to administer inhaled aerosols
are the MDI, small-volume nebulizer, and dry-powder inhaler.
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Principles of Pharmacology (cont.)
The drug administration phase (cont.)
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The advantages of inhaled aerosols are
 Can use smaller doses as compared to the systemic route
 Onset of drug is rapid
 Delivery is to the specific organ needing treatment
 Less systemic side effects
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Principles of Pharmacology (cont.)
The pharmacokinetic phase

Describe the time course and disposition of a drug in the body
based on its absorption, distribution, metabolism, and
elimination.
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Aerosols made up of medications that are fully ionized have little
or no systemic side effects (e.g., ipratropium).
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Principles of Pharmacology (cont.)
The pharmacodynamic phase

Describe the mechanisms of drug action by which a drug
molecule causes its effects in the body
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Drug effects are caused by combination of a drug with a
matching receptor.
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Principles of Pharmacology (cont.)
Airway receptors and neural control of the lung
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Sympathetic (adrenergic) and parasympathetic (cholinergic)
receptors are in the lung.
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The neurotransmitter in the sympathetic system is
norepinephrine (epinephrine).
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The neurotransmitter in the parasympathetic system is
acetylcholine.
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Principles of Pharmacology (cont.)
Airway receptors and neural control of the lung
(cont.)
Adrenergic: drug that stimulates a receptor responding to
norepinephrine or epinephrine
Antiadrenergic: drug that blocks a receptor for norepinephrine or
epinephrine
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Principles of Pharmacology (cont.)
Airway receptors and neural control of the lung (cont.)
Cholinergic: drug that stimulates a receptor for acetylcholine
Anticholinergic: drug that blocks a receptor for acetylcholine
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Adrenergic Bronchodilators
Indications for use
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Indication for short-acting agents
 For relief of acute reversible airflow obstruction
Indication for long-acting agents
 For maintenance bronchodilation in patients with obstructive
lung disease
Indication for racemic epinephrine
 To reduce airway swelling after extubation or with acute
upper airway inflammation from croup
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Adrenergic Bronchodilators (cont.)
Mode of action and effects
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-Receptor stimulation: causes vasoconstriction and a
vasopressor effect
1-Receptor stimulation: causes increased heart rate and heart
contractility
2-Receptor stimulation: relaxes bronchial smooth muscle,
stimulates mucociliary activity
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Adrenergic Bronchodilators (cont.)
Adverse effects
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Older adrenergic agents such as isoproterenol commonly
caused tachycardia, palpitations, and nervousness.
Newer 2-selective agents are safe, with tremor as the primary
side effect.
Tolerance to the drug may occur.
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Adrenergic Bronchodilators (cont.)
Assessment of bronchodilator therapy
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Based on the indication(s) for the aerosol agent
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Vital signs, breath sounds, and breathing pattern should be
evaluated before and after treatment.
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The patient’s subjective response is important to evaluate.
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Adrenergic Bronchodilators (cont.)
Indications for use
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Indication for anticholinergic bronchodilator
 Indicated for maintenance bronchodilator therapy for COPD
patients
Indication for combined anticholinergic and -agonist
 COPD patients
 Asthma patients
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Adrenergic Bronchodilators (cont.)
Mode of action

These agents act as competitive antagonists for acetylcholine
on airway smooth muscle.
Adverse effects
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Ipratropium bromide and tiotropium bromide have few systemic
side effects since they are fully ionized and are not absorbed.
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Adrenergic Bronchodilators (cont.)
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Mucus-Controlling Agents
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N-Acetyl-L-cysteine (NAC)
 Given by aerosol or direct tracheal instillation
 Given to reduce accumulation of airway mucus
 May cause bronchospasm due to its irritating side effects

Dornase alfa
 Indicated for the management of cystic fibrosis
 May cause voice alteration, pharyngitis, rash, or chest pain
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Mucus-Controlling Agents (cont.)
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Inhaled Corticosteroids
Indications and purposes
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Orally inhaled preparations are used for antiinflammatory
maintenance therapy of persistent asthma and severe COPD.
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The use of nasal steroids is for control of allergic and nonallergic
rhinitis.
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Inhaled Corticosteroids (cont.)
Mode of action
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Lipid-soluble drugs that act on intracellular receptors
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Full antiinflammatory effects require hours to days.
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Will not provide immediate relief of dyspnea from airways
obstruction
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Inhaled Corticosteroids (cont.)
Adverse effects
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Inhaled Corticosteroids (cont.)
Assessment of drug therapy
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Use strategies for assessment similar to those used for
evaluation of bronchodilators.
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In addition
 Make sure patient understands the importance of consistent
use and not to use it as a rescue drug.
 Instruct patient in the use of a peak flowmeter.
 Assess patient for side effects.
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Nonsteroidal Antiasthma Drugs
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A growing class of drugs for the treatment of asthma
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Three types exist
 Comolyn-like agents (cromolyn, nedocromil sodium)
 Antileukotrienes (zafirlukast, zileuton)
 Monoclonal antibodies or anti-IgE agents (omalizumab)
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Nonsteroidal Antiasthma
Drugs (cont.)
Indications for use
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Used for prophylactic management (control) of mild to moderate
persistent asthma
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May be used as an alternative to steroids in patients with
persistent asthma symptoms

Offer no benefit for acute airways obstruction in asthma
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Nonsteroidal Antiasthma
Drugs (cont.)
Adverse effects
Cromolyn-like agents
- Considered extremely safe
Antileukotriene agents
- Headache, dyspepsia, liver enzyme elevation
Omalizumab
- Injection site reaction, viral infections
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Nonsteroidal Antiasthma
Drugs (cont.)
Assessment of drug therapy
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Strategies similar to those used to assess initial bronchodilator
therapy
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Clinician should verify that the patient understands that these
medications are controller drugs and not rescue agents.
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Aerosolized Antiinfective Agents
Pentamindine isethionate
Has been used in the past for the treatment of Pneumocystis carinii
pneumonia (PCP)
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Due to limited efficacy, pentamindine is no longer recommended
for PCP treatment
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Common side effects include cough, bronchospasm and
wheezing, dyspnea, etc.
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Aerosolized Antiinfective
Agents (cont.)
Ribavirin
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An antiviral agent used in the treatment of severe lower
respiratory tract infections caused by respiratory syncytial virus
(RSV)
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Administration of the aerosol requires the use of a small particle
aerosol generator (SPAG).

Cost-effectiveness continues to be debated.
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Aerosolized Antiinfective
Agents (cont.)
Ribavirin (cont.)
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Adverse effects
 Skin rash
 Eyelid erythema
 Conjunctivitis
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Patients and practitioners who are pregnant should not be
exposed to ribavirin.
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Aerosolized Antiinfective
Agents (cont.)
Inhaled tobramycin
Intended to manage chronic infection with P. aeruginosa in
patients with cystic fibrosis

Side effects with the inhaled route are usually minimal and
include voice alteration and tinnitus.
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Aerosolized Antiinfective
Agents (cont.)
Colistimethate sodium
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An antibiotic used to treat sensitive strains of gram-negative
bacilli, particularly P. aeruginosa
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The most common side effect seen with the aerosol route is
bronchospasm.
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Aerosolized Antiinfective
Agents (cont.)
Inhaled zanamivir
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An inhaled powder
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Indicated for the treatment of uncomplicated acute illness due to
influenza virus in adults and children at least 7 years of age

Can cause bronchospasm and allergic reactions
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Aerosolized Antiinfective
Agents (cont.)
Use of aerosolized amphotericin B
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May be used in lung transplantation patients to prevent or treat
atypical infection
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The aerosolized route reduces the risk of renal damage.
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Can cause nausea, vomiting, and bronchospasm
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Inhaled Pulmonary Vasodilators
Nitric oxide (INOmax)
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Indicated for the treatment of neonates (<34 weeks) with
hypoxic respiratory failure and pulmonary hypertension
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It relaxes vascular smooth muscle in the pulmonary vasculature.
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The most common side effect is hypotension.
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Inhaled Pulmonary
Vasodilators (cont.)
Iloprost
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Used in the treatment of pulmonary hypertension
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Administered with the I-neb or Prodose nebulizer
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Acts by dilating the pulmonary vasculature
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Side effects include headache and increased cough
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Antidiabetic Agents
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Exubera is an inhaled insulin.
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Used to control hyperglycemia in diabetics
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Should not be used by patients who smoke
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Potential side effects include cough, dyspnea, pharyngitis,
increased sputum, and epistaxis.
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