Ppt chapter 30-1

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Adrenergic AgonistsAdrenergic Agonists

Chapter 30


Adrenergic AgonistsAdrenergic 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

Physiological Responses of Adrenergic Agonists


Alpha- and Beta-Adrenergic Agonists and Their Indications

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 AgonistsAlpha- 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


Alpha- and Beta-Adrenergic Agonists (cont.)


• Contraindications

– Pheochromocytoma

– Tachyarrhythmias or ventricular fibrillation

– Hypovolemia

– Halogenated hydrocarbon general anesthetics

– Caution should be used with peripheral vascular disease

• Caution

– PVD




• 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)

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-Specific Adrenergic Agonists (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


QuestionQuestion

Please identify the following statement as true or false.

Another name for an adrenergic agonist drug is a sympathomimetic drug.


AnswerAnswer

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

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 AgonistsBeta-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.)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.)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

Use of Adrenergic Agents Across the Lifespan


Prototype Alpha- and Beta-Adrenergic Agonists

Prototype Alpha- and Beta-Adrenergic Agonists


Prototype Alpha-AgonistsPrototype Alpha-Agonists


Prototype Beta-Specific Adrenergic Agonists

Prototype Beta-Specific Adrenergic Agonists


Nursing Considerations for Alpha- and Beta-Adrenergic Agonists

Nursing Considerations for Alpha- and Beta-Adrenergic Agonists

• Assessment: History and Physical Exam

• Nursing Diagnosis

• Implementation

• Evaluation


Nursing Considerations for Alpha-Agonists

Nursing Considerations for Alpha-Agonists



• Implementation

• Evaluation


Nursing Considerations for Beta-Specific Adrenergic Agonists

Nursing Considerations for Beta-Specific Adrenergic Agonists



• Implementation

• Evaluation


QuestionQuestion

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


AnswerAnswer

B. Pheochromocytoma

Rationale: Assess for contraindications or cautions including pheochromocytoma which could lead to fatal reactions

due to systemic overload of catecholamines.

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