Ppt chapter 30-1

Adrenergic Agonists
Chapter 30
Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Adrenergic Agonists
• Definition
– Called sympathomimetic drugs because they mimic
the effects of the sympathetic nervous system (SNS)
• Therapeutic and Adverse Effects
– Related to their stimulation of adrenergic receptor
sites
• Uses
– Varies from ophthalmic preparations for dilating
pupils to systemic preparations for shock

Physiological Responses of Adrenergic
Agonists

Alpha- and Beta-Adrenergic Agonists and
Their Indications
• Epinephrine (Adrenalin, Sus-Phrine): Shock; glaucoma;
prolongs effects of regional anesthetic
• Norepinephrine (Levophed): Treat shock or during
cardiac arrest to get sympathetic activity
• Dopamine (Intropin): Shock
• Dobutamine (Dobutrex): Congestive heart failure
• Ephedrine (Pretz-D): Seasonal rhinitis; hypotensive
episodes
• Metaraminol (Aramine): Synthetic agent that is similar to
norepinephrine

Alpha- and Beta-Adrenergic Agonists
• Actions
– The effects of these drug are mediated by the adrenergic
receptors in target organs; heart rate increases, bronchi dilate,
vasoconstriction occurs, intraocular pressure decreases,
glycogenolysis occurs throughout the body
• Indications
– Treatment of hypotensive shock, bronchospasm, and some types
of asthma
• Pharmacokinetics
– Rapidly absorbed after injection or passage through mucous
membranes
– Metabolized in the liver and excreted in the urine

(cont.)
• Contraindications
– Pheochromocytoma
– Tachyarrhythmias or ventricular fibrillation
– Hypovolemia
– Halogenated hydrocarbon general anesthetics
– Caution should be used with peripheral vascular
disease
• Caution
– PVD

(cont.)
• Adverse Reactions
– Arrhythmias, hypertension, palpitations, angina,
dyspnea
– Nausea and vomiting
– Headache and sweating
• Drug-to-Drug Interaction
– Tricyclic antidepressants and MAOI’s

Alpha-Specific Adrenergic Agonists
(Alpha-Agonists)
• Definition
– Drugs that bind primarily to alpha-receptors rather
than to beta-receptors
• Drugs In This Class
– Phenylephrine (Neo-Synephrine, Allerest, AK-Dilate,
and others)
– Midodrine (ProAmantine)
– Clonidine (Catapres)

(Alpha-Agonists) (cont.)
• Actions
– Therapeutic effects come from the stimulation of alpha-receptors
within the SNS
• Indications
– Hypertension, constriction of topical vessels in nose
– Well absorbed and reach peak levels in a short period—20
to 45 minutes
– Widely distributed in the body

– Allergy to drug
– Severe hypertension or tachycardia
– Narrow-angle glaucoma
– Pregnancy
• Caution
– CVD or vasomotor spasm
– Thyrotoxicosis or diabetes

– Anxiety, restlessness, depression, fatigue, blurred
vision
– ECG changes, arrhythmias, blood pressure changes
– Nausea, vomiting
– Decreased urinary output
– MAOIs and TCAs
– Digoxin and beta-blockers

Question
Please identify the following statement as true or false.
Another name for an adrenergic agonist drug is a
sympathomimetic drug.

Answer
True
Rationale: An adrenergic agonist is also called a
sympathomimetic drug because it mimics the effects of
the sympathetic nervous system (SNS).

Beta-Specific Adrenergic Agonists and
Their Indications
• Isoproterenol (Isuprel)
– Treatment of shock, cardiac standstill, and heart
block in transplanted hearts; prevention of
bronchospasm during anesthesia; inhaled to treat
bronchospasm
• Ritodrine (Yutopar)
– Management of preterm labor

Beta-Specific Adrenergic Agonists
• Actions
– Effect is related to its stimulation of the beta-adrenergic
receptors
– Increase heart rate, conductivity, and contractility,
bronchodilation, increase blood flow to skeletal muscles
and splanchnic bed, and relaxation of uterus
– Rapidly distributed after injection
– T ½ less than 1 hour

Beta-Specific Adrenergic Agonists (cont.)
– Allergy
– Pulmonary hypertension
– Eclampsia, uterine hemorrhage, and intrauterine death
– Pregnancy and lactation
• Caution
– Diabetes, thyroid disease
– Vasomotor problems
– Heart disease and stroke

Beta-Specific Adrenergic Agonists (cont.)
– Restlessness, anxiety, and fear
– Tachycardia, angina, MI, and palpitations
– Difficulty breathing, cough, and bronchospasm
– Nausea, vomiting, and anorexia
– Increase with other sympathomimetic drugs
– Decrease with beta adrenergic blockers

Use of Adrenergic Agents Across
the Lifespan

Prototype Alpha- and Beta-Adrenergic
Agonists

Prototype Alpha-Agonists

Prototype Beta-Specific Adrenergic
Agonists

Nursing Considerations for Alpha- and
Beta-Adrenergic Agonists
• Assessment: History and Physical Exam
• Nursing Diagnosis
• Implementation
• Evaluation

Nursing Considerations for
Alpha-Agonists
• Implementation
• Evaluation

Nursing Considerations for Beta-Specific
Adrenergic Agonists
• Implementation
• Evaluation

Question
When providing care for a patient receiving alpha and beta
adrenergic agonists, which of the following would be
important to assess in order to prevent the systemic
overload of catecholamines?
A. Hypotension
B. Pheochromocytoma
C. Hypovolemia
D. Allergic rhinitis

Answer
B. Pheochromocytoma
Rationale: Assess for contraindications or cautions
including pheochromocytoma which could lead to fatal
reactions due to systemic overload of catecholamines.

Ppt chapter 30-1

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