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Chapter 22
Respiratory and
Gastrointestinal Drugs
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Sympathomimetic Agents
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Noninfectious respiratory diseases are
divided into two groups.
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Asthma is characterized by reversible airway
obstruction.
Chronic obstructive pulmonary disease
(COPD) is characterized by irreversible airway
obstruction.
• COPD is further divided into emphysema and chronic
bronchitis.
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Sympathomimetic Agents
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Beta-Adrenergic Agonists
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Nonselective adrenergic agonist drugs stimulate
beta receptors in the lungs and heart and alpha
receptors in the heart.
Epinephrine and isoproterenol are nonselective
adrenergic agonists.
Today, short- and long-acting β2-agonists are used
to treat asthma and COPD.
Β2-Agonists stimulate receptors in the lungs.
Stimulation of these receptors produces
bronchodilation.
Adverse effects include nervousness, tachycardia,
and insomnia.
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Respiratory Drugs
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Beta-Adrenergic Agonists
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Short-Acting β2-Agonists
• These drugs are used to treat acute asthma attacks.
• They are usually administered via metered dose
inhalers.
• They are available in tablet and liquid dose forms.
• Short-acting β2-agonists are often used as
prophylaxis prior to exercise or another known
precipitating event.
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Long-Acting β2-Agonists
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These agonists have a delayed onset of
action and a longer duration of action.
Onset of action is within 10-20 minutes
and the duration of action of 12 hours.
These drugs are used as maintenance
therapy in the treatment of asthma and
COPD.
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Metered Dose Inhalers (MDI)
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These devices deliver the medication directly to
the bronchioles.
The total dose is kept low and side effects should
be minimal.
The inhaled dose can be accurately measured.
Onset of action is rapid and predictable.
They are compact, portable, and sterile.
They can be difficult to use.
Spacers are available which makes the inhaler
easier to use.
Adverse effects with MDI use include dry mouth.
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Corticosteroids
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Steroids reduce the inflammation
associated with airway obstruction.
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They also inhibit the release of inflammatory
substances.
 Steroids are available as MDIs and oral and
liquid dose forms.
 The MDI has become the most common dose
form used in treating asthma and COPD.
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Corticosteroids
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Corticosteroids significantly improve
pulmonary function with a decrease in
wheezing, tightness, and cough.
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These drugs are not used for acute attacks.
 Chronic oral prednisone use is reserved for
patients with severe asthma.
 Adverse effects are dependent upon dose
form, frequency of intake, total dose, and any
preexisting conditions.
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Corticosteroids
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Prolonged systemic use can lead to
adrenal suppression, poor wound healing,
and immunosuppression.
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MDI use can lead to oral candidiasis.
Patients using inhaled steroids should be
instructed to brush, floss, rinse, and spit, after
each use.
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Leukotriene-Pathway Inhibitors
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These drugs work by either preventing the
synthesis of leukotrienes or by blocking
leukotriene receptors.
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Leukotriene release produces
bronchoconstriction, increased mucus
secretion, mucosal edema, and increased
bronchial hyperreactivity.
 These drugs are used to treat asthma and
allergic rhinitis.
 Adverse reactions include irritation of the
stomach mucosa, headache, and altered liver
function tests.
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Cromolyn
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Cromolyn inhibits mast cell degranulation.
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It is used for the prophylaxis of asthma.
 It can be used in patients with chronic asthma
or taken before exercise-induced asthma.
 Adverse effects include cough, dry mouth,
nausea, and headache.
 It is available as a nebulizer or in a spinhaler
dose form.
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Methylxanthines
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Theophylline is the main drug in this
category.
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It is a bronchodilator with a narrow therapeutic
window.
 It is used to treat severe asthma and the
bronchospasm associated with COPD.
 Side effects include CNS stimulation, cardiac
stimulation, and GI upset.
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Anticholinergic Drugs
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Ipratropium bromide is an inhaled
anticholinergic drug that is used to treat
asthma and COPD.
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Its anticholinergic effects produce a
bronchodilating effect in the lungs.
Side effects include dry mouth. The patient
should rinse after each inhaler use to minimize
dry mouth.
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Nasal Decongestants
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Nasal decongestants are α-agonists that
act by constricting the blood vessels of the
nasal mucous membranes.
Chronic use of topical decongestants can
lead to rebound swelling and congestion.
Adverse effects include insomnia,
excitation, and tachycardia.
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Expectorants and Mucolytics
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Expectorants promote the removal of
exudate or mucous from the respiratory
passages.
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Mucolytics destroy or dissolve mucus.
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Antitussives
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These agents are used for the
symptomatic relief of nonproductive cough.
Opioids and dextromethorphan are the
most common antitussives.
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Dental Implications of the
Respiratory Drugs
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Gastrointestinal Diseases
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Gastrointestinal reflux disease (GERD) is a dental
concern in and of itself.
Patients with GERD may not be able to remain in a
supine position in the dental chair. A supine position
may stimulate acid reflux.
The chair should be raised until the patient is
comfortable. In some instances, the chair may need to
be in a fully seated position.
Ulcers affect the stomach and small intestine.
Patients with either ulcers or GERD should avoid
aspirin and NSAIDs to treat dental pain.
These drugs are irritating to the stomach and can
cause ulcers and exacerbate symptoms of GERD.
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Gastrointestinal Drugs
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Classes of drugs used to treat GERD and peptic
ulcer disease are many.
They include histamine2-receptor blockers, proton
pump inhibitors, and antacids. H2-blockers block
gastric acid secretion by blocking the H2-receptors
of the parietal cells.
Proton pump inhibitors are potent inhibitors of
gastric acid secretion.
Antacids neutralize stomach acid production.
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Gastrointestinal Drugs
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Most patients self-treat with antacids or over-thecounter H2-blockers or omeprazole.
Patients should be questioned about their use of
these drugs during dental appointments.
Some oral adverse effects include mucosal
atrophy of the tongue and dry mouth.
H2-blockers interact with ketoconazole,
itraconazole, and benzodiazepines.
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Gastrointestinal Drugs
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Ulcers may also be due to the bacteria H. pylori.
Patients usually receive a combination of an
antibiotic and either an H2-blocker or a proton
pump inhibitor to treat this.
Misoprostol is a prostaglandin that is used to treat
and prevent drug-induced ulcers.
Sucralfate is a complex of aluminum hydroxide
and sulfated sucrose.
It is used to treat peptic ulcer disease.
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Gastrointestinal Drugs
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Sucralfate binds with proteins and forms a
complex that acts as a “bandage” on the ulcer
site.
Adverse effects include constipation, dry mouth,
nausea, rash, and dizziness.
Metoclopramide is a dopamine antagonist that
stimulates the motility of the upper GI tract. It
leads to an accelerated gastric emptying time.
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Gastrointestinal Drugs
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Adverse effects include restlessness, drowsiness,
fatigue, and extrapyramidal side effects.
Simethicone is combined with antacids and is
used to relieve flatulence.
Simethicone lowers surface tension and breaks
up gas pockets.
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Laxatives
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Laxatives are used for a variety of reasons
to include the treatment of constipation
and bowel cleansing prior to certain
procedures.
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Bulk laxatives are considered more natural and
increase peristalsis and facilitate movement
through the intestine.
Lubricants can interfere with the absorption of
fat-soluble vitamins and are no longer
recommended.
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Laxatives
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Stimulant laxatives act by producing local
irritation to the intestinal mucosa.
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Stool softeners accumulate water in the
intestine and soften the stool so that it is easily
expelled from the body.
Osmotic or saline laxatives produce their effect
by osmotically holding water.
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Antidiarrheals
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Drugs used to treat diarrhea are either
adsorbents or opioid-like in action.
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They are used to minimize fluid and electrolyte
imbalances.
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Emetics
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These drugs are used to treat people who
have ingested or overdosed drugs that can
be harmful.
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Antiemetics
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Vomiting can occur for any number of
reasons to include the flu, motion
sickness, pregnancy, drugs, infections, or
chemotherapy.
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Phenothiazines are used to control severe nausea.
Anticholinergic and antihistamine drugs are used for
nausea and vomiting due to motion sickness.
Other antiemetics include trimethobenzamide,
metoclopramide, benzquinamide, and cannaboids which
are used for cancer chemotherapy patients.
All of these drugs cause sedation, dizziness, and dry
mouth.
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