Respiratory: Inhaled Anti-Inflammatory Agents

Question 1

Types of Respiratory Drugs:

Bronchodilators: Beta2-Receptor Agonists:

Basic Understanding:

Answer 1

Cromolyn sodium and nedocromil are synthetic compounds
that inhibit antigen-induced bronchospasm. Cromolyn was
originally produced to be used as a bronchodilator but was
found to have no bronchodilator activity. Nevertheless, cromolyn inhibits antigen-induced bronchospasm, blocks the
release of histamine, and is a mast cell stabilizer. Nedocromil
is similar to cromolyn in many ways but is now only available
in ophthalmic solution, which is discussed in Chapter 27.
Cromolyn is used in the treatment of asthma; it (Nasalcrom)
is also used in treating allergic rhinitis.

Question 2

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacodynamics:

Answer 2

Cromolyn acts to inhibit mast cell degranulation, which prevents the release of histamine and slow-reacting substance of
anaphylaxis (SRS-A). Neither drug prevents the binding of
IgE to the mast cell or the binding of antigen to IgE. Cromolyn also prevents the release of leukotrienes, which induce
numerous effects that contribute to the inflammatory process
in the lungs. With continued use, cromolyn reduces bronchi
hyperreactivity to stimuli such as cold air, allergens, and environmental irritants. Cromolyn does not have bronchodilator, antihistamine, or vasoconstrictor activity, and at therapeutic
doses, does not have systemic activity

Question 3

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacokinetics: Absorption and Distribution:

Answer 3

Inhaled cromolyn is poorly absorbed systemically; only 8%
of the dose is absorbed. Approximately 5% to 10% of the inhaled dose reaches the lungs, with the amount affected by the
degree of bronchoconstriction present. Intranasal cromolyn
is minimally absorbed. Distribution of the absorbed amount
of the drug is unknown. Minimal amounts of cromolyn cross
the placenta and distribute into breast milk.

Question 4

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacokinetics: Metabolism and Excretion:

Answer 4

The portion of the dose of cromolyn that is absorbed from
the lung is rapidly excreted unchanged in the urine and bile.
The remaining portion of the dose is exhaled or swallowed
and excreted unchanged in the feces.

Question 5

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacotherapeutics: Precautions and Contraindications:

Answer 5

Cromolyn is not a bronchodilator, and it is contraindicated in
the treatment of acute bronchospasm or status asthmaticus.
Hypersensitivity to cromolyn is a contraindication to its use.
Cromolyn is Pregnancy Category B and should be used
with caution in the lactating mother because safety has not
been established. Cromolyn is safe for use in children as
young as 2 years (nebulizer solution).

Question 6

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacotherapeutics: Adverse Drug Reactions:

Answer 6

Cromolyn is generally well tolerated. Inhaled cromolyn may
cause bronchospasm, which can be avoided by preadministering a beta-agonist bronchodilator. Throat irritation and
cough are also reported. Intranasal cromolyn may produce
nasal irritation and cause sneezing.

Question 7

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacotherapeutics: Drug Interactions:

Answer 7

There are no clinically significant drug interactions with
cromolyn. Cromolyn solution for nebulizer use will form a
precipitate if mixed with ipratropium solution.

Question 8

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacotherapeutics: Rational Drug Selection:

Answer 8

The decision regarding which inhaled anti-inflammatory to
use is often based on cost, availability, and patient variables
such as age or ease of dosing.

Patient Variables

Cromolyn has dosage forms available for use in children as
young as 2 years.

Administration

Cromolyn comes in multiple formulations that allow the
provider to match the patient’s age and lifestyle with an administration form. Cromolyn MDI (Intal) has been discontinued in the United States, but generic inhalation solution
for nebulizer use is available.

Cost

Cromolyn is available in generic nebulizer solution; the cost
of 96 ampules is $212.

Question 9

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacotherapeutics: Monitoring

Answer 9

No specific monitoring is required other than monitoring

associated with the disease process.

Question 10

Types of Respiratory Drugs:

Bronchodilators: B2RAs:

Pharmacotherapeutics:
Patient Education:

Answer 10

Administration

The administration of inhaled anti-inflammatory agents requires the patient to use the medication as prescribed.
Cromolyn is not effective if not used at regular intervals. Clarification regarding the use of inhaled bronchodilators that
can be used as needed and the inhaled anti-inflammatory
agents will enable the patient to use the medication appropriately, as will a written plan.
The use of cromolyn via nebulizer must be demonstrated
to the patient in the clinic or by the home health agency that
is providing the nebulizer. Because the vials are premeasured,
there is no concern about dosing error.

Adverse Reactions

At therapeutic dosages, minimal adverse reactions are reported. The patient should be instructed not to exceed the
recommended dosage of the medication.

Lifestyle Management

Lifestyle management issues related to the disease process being
treated should be discussed. They often include the following:
1. The patient needs to self-monitor respiratory status
with a peak flowmeter to determine the effectiveness
of the medication prescribed.
2. The patient should avoid or quit smoking.
3. The patient should avoid environmental triggers for
the asthma at home, work, and school.