Bronchodilators
Lilley Pharmacology Text: Chapter 35

Original PPT modified by:

Anita A. Kovalsky, R.N., M.N.Ed.

Professor of Nursing

Original by: Professor Edwards,

 

 

 

Review of Glossary Terms:
Lilley pg. 542

•Alveoli:

•Antigen:

•Antibody:

•Asthma Attack:

•Bronchial Asthma:

•Chronic Bronchitis:

•Emphysema:

ADDITIONAL TERMS

•Acute:

•Exacerbation:

Diseases commonly treated with Bronchodilators

 

•Asthma

           http://www.whatsasthma.org

COPD

                        Chronic Bronchitis

                        Emphysema

 

BRONCHODILATOR CLASSIFICATIONS

Bronchodilators:

 

ό        Xanthines Derivatives

 

ό        Beta-Agonists

 

Xanthine Derivatives
(Refer to Prototype List in syllabus, pg. 19)

•Prototype Drugs:

 

–Theophylline- Theo-dur

 

–Aminophylline

 

 

 

 

How Do These Drugs Work?

•Relieve Bronchoconstriction

 

 

 

 

 

 

•Cause bronchodilatation

 

 

 

Mechanism of Action

•Cause bronchodilation by:

–Increasing the levels of the energy producing substance called cAMP

–Inhibiting PDE the enzyme that breaks down *cAMP….

–Subsequently, this causes smooth muscle relaxation and broncchodilation; also inhibits release of chemical mediators such as histamine, etc.

–*cAMP = cyclic adenosine monophosphate

 

 

Mechanism of Action contd.

•Slow onset of action, so used more as preventative measure, however, also used as a continuous IV infusion to treat reversible bronchospasm in COPD clients who have an exacerbation of symptoms

Drug Effects

•Relieve bronchopasms by causing airways to dilate, thereby improving air passage into and out of lungs

 

•Stimulates CNS:

–Increases contractility of heart (+ inotropic)

–Increases heart rate  (+chrontropic)

–Increases cardiac output, thereby causing a….

–Diuretic effect…what would cause this???????

Therapeutic Uses

•Dilate airways in asthma, chronic bronchitis and emphysema

 

•Adjunctive agent for treatment of pulmonary edema and dyspnea in left-sided heart failure by increasing cardiac output and increasing bloodflow to kidneys ΰdiuresis

 

 

 

Lab Diagnostics
Cavanaugh Text: pg. 215

Side and Adverse Effects

•Nausea

•Vomiting

•Anorexia

•Gastroesophageal reflux

 

CARDIAC!!!!!!!! HIGH ALERT!!!!

•Sinus Tachycardia

•Palpitations

•Ventricular Dysrhythmias

 

•Hyperglycemia (transient)

•Increased urinary output (transient)

 

 

 

Interactions

•Allopurinol

•Cimetidine

•Erythromycin

•Flu Vaccine

•Oral Contraceptives

 

•Need blood levels monitored closely

Available Theophylline Preparations

–Oral

 

–Parenteral

      (aminophylline infusion)

 

–Rectal

Beta-Agonists or Sympathomimetic Bronchodilators
 (Refer to Prototype List in syllabus, pg. 19
    Also listed in Lilley, pg. 548)

•Prototype Drugs: (Brand name    in parentheses)

              - Albuterol (Proventil) Beta2 Selective

OTHERS:

-Ephedrine

-Epinephrine  (Adrenalin, Primatene, Bronkaid)

-Terbutaline (Brethine)

 

 

 

 

 

 

When are Beta-Agonists used?

•During acute phase of asthmatic attack

•To quickly reduce airway constriction and cause bronchodilation

 

WHY ARE THEY CALLED AGONISTS????

•AGONISTS or stimulators of SNS receptors----->   

              SYMPATHOMIMETIC ACTION

 

WHAT IS THE PRIMARY MECHANISM OF ACTION??

•Imitate the effects of norepinephrine on receptors

 

•Stimulate beta2-adrenergic receptors in the lungs causing dilation within the airways of the lungs (Example: Albuterol/Proventil)

 

 

Specific Receptors
Refer to Lilley text, pg. 547

•Nonselective adrenergic: stimulate the alpha,  beta1 (cardiac), and beta2-  (respiratory) receptors  (Example: epinephrine)

 

•Nonselective beta-adrenergic: stimulate both beta1 and beta2 receptors (Example: Isuprel)

 

•Selective beta2: stimulate the beta2 receptors (Example: albuterol)

Drug Effects

**SELECTIVE BETA2

•Beta2 stimulationΰ causes bronchodilation; also a decreased diastolic B/P, decreased K+ level

 

Mechanism of Action

•Begins with specific receptors stimulated and ends with the dilation of airways

•cAMP is activated when a beta2-adrenergic receptor is stimulated

•Smooth muscles relax and airflow increased

 

 

 

Therapeutic Uses of
Beta-Agonists

•Pulmonary disorders for relief of bronchospasm

 

•Nonselective: Used for hypotension and shock treatment and to relieve nasal congestion and stuffiness

 

Bronchodilators:  Beta-Agonists
Side Effects

Alpha-Beta       Beta1 and Beta2            Beta2

(epinephrine)    (isoproterenol)  (albuterol)

Insomnia                   cardiac stimulation         hypotension
restlessness              tremor                            vascular headache
anorexia                    anginal pain         
cardiac stimulation    vascular headache         tremor
vascular headache

Interactions

 

•Beta-agonist with nonselective beta-adrenergic blocker (beta-blocker)ΰ antagonizes the bronchodilation effect!!!

 

•Avoid MAO inhibitors

 

 

Available Selected
Beta-Agonist Preparations

•PO

•SC

•Inhaler

•Nebulizer

•IM

Nursing Considerations for Bronchodilators

•Does the client have cardiac disease??

•If so, which type of bronchodilator should be the drug of choice??

•Does the client have diabetes??

•If the client is receiving a xanthine, what blood levels should be monitored???

 

A client is receiving IV aminophylline for a severe exacerbation of COPD. Which of the following would you expect when evaluating for a therapeutic response to the medication?

A.  Drowsiness
B.  Increased heart rate
C.  Dilatation of bronchioles
D.  Increased respiratory rate

Which of the following side effects is associated with the use of xanthine derivatives?

A.  Bradycardia
B.  Palpitations
C.  Increase in appetite
D.  Constriction of bronchioles

Overview of Drugs Affecting
the Respiratory System

•Bronchodilators

–Xanthine derivatives

–Beta-agonists

•Anticholinergics

•Antileukotriene agents

•Corticosteroids

•Mast cell stabilizers


THE END