8 Intro and Adrenergic Agonists

What is the term for the process nurses use to observe, interpret, and respond to patient data in order to make safe care decisions? It's how you go beyond “following the steps” to actually reasoning through whether a medication is safe for this patient, right now.

CJMM (Clinical Judgement Measurement Model)

Which portion of the CJMM involves gathering patient data: vitals, history, allergies, labs, current symptoms?

Recognize Cues

Which portion of the CJMM involves asking what the data gathered means for the medication you're about to give?

Analyze Cues

Which portion of the CJMM involves identifying the most likely problem or highest-risk contraindication?

Prioritize Hypothesis

Which portion of the CJMM involves deciding the safe dose/route, administer, or advocate for an alternative?

Generate Solutions & Take Action

Which portion of the CJMM involves reassess what you did and asking questions such as “Did it work?” and/or “Any new or adverse effects?'“

Evaluate Outcomes

What are the 10 Rights of Medication Administration.

Client, Medication, Dose, Route, Time, Assessment, Documentation, to Refuse, Education, Evaluation

What are the functions of the ANS?

Regulates the Heart, Secretory Glands, and Smooth Muscles

The following suggest which action of the Autonomic Nervous System?

• ↑ Heart rate (tachycardia)

• ↑ Blood pressure (hypertension)

• Bronchodilation (opens airway)

• Vasoconstriction -> shunts blood away from peripheral vessels

Adrenergic (Sympathetic)

The following suggest which action of the Autonomic Nervous System?

• ↓ Heart rate

• ↓ Blood pressure (vasodilation)

• Bronchial constriction

• Bladder contraction -> allows urination

• Pupil constriction (miosis)

• ↑ GI motility & secretions

• ↑ Salivation & lacrimation

Cholinergic (Parasympathetic)

What is the term for a drug that mimics a sympathetic response in the body such as increasing HR, increasing BP, or bronchodilation?

Sympathomimetic

What is the term for a drug that blocks parasympathetic effects in the body which can cause dry mouth, urinary retention, or tachycardia?

Anticholinergic

What are the adrenergic receptors of the ANS?

a1, a2, B1, B2

What are the cholinergic receptors of the ANS?

Nicotinic and Muscarinic

The a1 adrenergic receptor can be found mainly where in the body?

blood vessels (& eye, bladder, neck)

The a2 adrenergic receptor can be found mainly where in the body?

presynaptic nerve terminals (aka nerve endings, & CNS)

The B1 adrenergic receptor can be found mainly where in the body?

Heart (high dose) and Kidney (low dose)

The B2 adrenergic receptor can be found mainly where in the body?

Bronchi (& blood vessels, uterus)

When giving a drug to lower the BP of a pt who has hypertension, you notice that BP is starting to increase. What explains this phenomenon?

• this same phenomenon can also happen if the BP was opposite

Baroreceptors (Baroceptor Reflex)

What is the primary effect when the a1 receptors are activated?

Vasoconstriction (pupil dilation, urinary retention, smooth muscle contracts)

What is the primary effect when the a2 receptors are activated?

lower NE release (autoinhibition; inverse reaction of the other adrenergic receptors)

What is the primary effect when the B1 receptors are activated?

increase HR (increase contractility, increase renin)

What is the primary effect when the B2 receptors are activated?

bronchodilation (uterine relaxation, increase glucose)

What is the example drug of the Alpha 1 Agonist?

phenylephrine (aka Sudafed PE, Neo-synephrine: intranasal or ophthalmic, Vazculep- IV)

What are the therapeutic uses of Phenylephrine (Sudafed PE)?

• Nasal decongestion (PO or intranasal)

• Mydriasis – pupil dilation for eye exams

• Adjunct (similar) to local anesthesia (epi + lidocaine → prolongs effect)

• Hemostasis – topical epinephrine controls bleeding

• Raise blood pressure (IV norepinephrine – Critical Care)

What are the Adverse Effects of Phenylephrine (Sudafed PE)?

• Hypertension (can be severe with IV use)

• Bradycardia (baroreceptor reflex)

• Tissue necrosis if IV extravasates (leaves blood vessels and into the surrounding tissue)

• Rebound congestion with overuse of nasal sprays

• Contraindicated in uncontrolled hypertension (remember it causes vasoconstriction – agonist)

What adverse effect is a priority nursing concern can be severe with IV administration of Phenylephrine?

Hypertension

What adverse effect is a priority nursing concern of Phenylephrine, an Alpha 1 Agonist, regarding the baroreceptor reflex?

Bradycardia

What adverse effect is a priority nursing concern if Phenylephrine (Sudafed PE) extravasates/infiltrates when given IV?

Tissue Necrosis

What is the example drug of the Alpha 2 Agonist?

Clonidine (Catapres, Catapres-TTS)

What are the therapeutic uses of Clonidine (Catapres)?

• Hypertension – activates presynaptic α2 receptors → ↓ sympathetic stimulation outflow → ↓ BP

• ADHD (off-label) – reduces hyperactivity/impulsivity centrally

• Opioid, alcohol, and nicotine withdrawal – blunts autonomic symptoms (tachycardia, sweating, anxiety)

• Severe cancer pain (epidural) – adjunct to opioid analgesia

• ADHD / Tourette's tics (off-label)

When a patient receives Clonidine (Catapres) as patches, what must the nurse educate the patient regarding the use of patches?

change patches every 3 days

What are the Adverse Effects of Alpha 2 Agonist drug such as Clonidine (Catapres)?

• Rebound hypertension if stopped abruptly – can be severe, mimics a hypertensive crisis. Watch the patches (TTS)!!

• Bradycardia

• Sedation / drowsiness

• Dry mouth

• Orthostatic hypotension / dizziness

true or false: Clonidine can never be discontinued abruptly and must be tapered

true

What is the example drug of the Beta 1 Agonist?

Dobutamine

What are the therapeutic uses of Dobutamine?

• Heart failure

• Cardiac stress tests

• Cardiogenic shock

• AV heart block (epinephrine → speeds conduction increasing heart rate)

• Cardiac arrest – stimulate the electrical activity of the heart (epinephrine)

What are the Adverse Effects of Dobutamine?

• Tachycardia (can worsen dysrhythmias, especially dopamine)

• Dysrhythmias

• Angina pectoris (↑ O2 demand)

• Caution with AV block: may accelerate ventricular rate

What is the example drug of the Beta 2 Agonist?

Albuterol (ProairHFA, Ventolin)

What are the therapeutic uses of Albuterol?

• Asthma / COPD – bronchodilation (inhaled albuterol preferred)

• Prefer β2-selective agents to minimize cardiac side effects

• Delay preterm labor (tocolysis)

• Rapid onset (inhaled) – ideal for acute bronchospasm

What are the Adverse Effects of Albuterol?

• Hyperglycemia (↑ glycogenolysis → problem in DM!)

• Muscle tremors

• Tachycardia (non-selective agents have β1 spillover)

• Hypokalemia with high doses

Which special adrenergic agonists is used for shock and or acute heart failure?

• Given: IV only, weight-based dosing, very short half-life

Dopamine

If a pt was given a low dose of Dopamine, what is the expected outcome?

renal vasodilation

If a pt was given a medium dose of Dopamine, what is the expected outcome?

acts on B1 → increase HR & increase CO

If a pt was given a high dose of Dopamine, what is the expected outcome?

acts on a1 → vasoconstriction & increase BP

What are the adverse effects of Dopamine?

dysrhythmias, angina, tissue necrosis (if IV extravasates)

Which special adrenergic agonists stimulates ALL alpha & beta receptors and can be used for:

• a1: vasoconstriction, hemostasis, adjunct to local anasthetic

• B1: cardiac arrest, AV block reversal

• B2: bronchodilation

Epinephrine

What is the primary use for Epinephrine?

Anaphylaxis / Anaphylactic Shock

What is important to keep in mind when administering Epinephrine based on the route whether it be IM, SC, IV, or Inh?

concentration