1
9/28/21 PHARM ADRENERGIC AGONISTS AND ANTAGONISTS
Adrenergic Agonists & Antagonists
Readings
● Chapter #15
McCuiston, L.E., Vuljoin-DiMaggio, K., Winton, M., & Yeager, J.J. (2021) Pharmacology: A
patient-centered nursing process approach (10th ed.). Canada: Saunders/Elsevier Inc.
The Nervous System
The Sympathetic Nervous System / adrenergic nervous system
o (arousing)
● “Fight or Flight” Response
○ Effects on the body
● Neurotransmitters
○ Epinephrine, Dopamine, Norepinephrine → catecholamines
○ Endogenous or exogenous (synthetic)
● Adrenergic receptors
ADRENERGIC RECEPTORS
Alpha1 (ɑ1) Beta1 (�1)
● Blood vessels→ vasoconstriction, ● Heart: increased heart contraction,
increase BP, increased contractility of increased HR
the heart ● Kidney: increased renin secretion,
● Eye → mydriasis(pupil dilation) increased angiotensin, increased blood
● Bladder → relax pressure
● Prostatic → contraction
Alpha2 (ɑ2) Beta1 (�2)
● Blood vessels → decrease blood ● Smooth muscle (GI) → decreased GI
pressure motility and tone
● Smooth muscle (GI tract) → decrease ● Lungs → bronchodilation
GI motility and tone ● Uterus → relaxation of uterine smooth
muscle
● Liver → activation of glycogenolysis,
increased blood sugar
Dopaminergic Receptors
● Located in renal, mesenteric, coronary, and cerebral arteries
● Causes vasodilation and increased blood flow
● _______________ is the only neurotransmitter medication that can activate this receptor
Adrenergic Medications
Adrenergic Agonists
● AKA: sympathomimetics
● Stimulate the sympathetic nervous system because they __________ endogenous
sympathetic neurotransmitters
● Act on adrenergic receptors at target sites
● Classifications
● Direct Acting
○ Epinephrine (Epi) and norepinephrine (NE)
, 2
9/28/21 PHARM ADRENERGIC AGONISTS AND ANTAGONISTS
○ Directly stimulates adrenergic receptors
● Indirect Acting
○ Amphetamine
○ Stimulates the release of NE from terminal nerve endings
● Mixed Acting
○ Ephedrine and pseudoephedrine
○ Stimulates adrenergic receptor sites and stimulates the release of NE from
terminal nerve endings
● selective vs. non-selective
○ Target organs
Epinephrine: Adrenergic Agonists
Action Uses
● Potent inotrope → vasocontriction and ● Anaphylaxis
bronchodilation ● Bronchospasms, status asthmaticus
● Non-selective adrenergic agonist ● Cardiogenic shock, cardiac arrest
● Given IV, IM, or ET
Side Effects/Adverse Reactions Contraindications
● Tachycardia, dysrhythmias, ● Use with caution in pt taking Digoxin
palpitations → dysrhythmia
● Hypertension, headache, dizziness ● Tricyclic Antidepressants &
● Insomnia, restlessness, tremors monoamine oxidase inhibitors →
intensive and prolong effects of epi
● Beta blockers → antagonistic effect
Nursing Interventions
● Obtain and record vital signs (BP & HR)
● Monitor urine output & IV site for infiltration
● Report rhythm tremors, dizziness, HTN, and palpitations
● Avoid cold medicines and diet pills if hypertensive
● Antidote: phentolamine mesylate
ALBUTEROL: ADRENERGIC AGONIST
Action Uses
● Selective (�2) ● Asthma → emergency and
● Bronchodilation bronchospasm prophylaxis
Side Effects/Adverse Drug Reactions Nursing interventions
● Tremor, nervousness, anxiety Teach pt. how to use, rinse mouth
● Tachycardia, hypertension, after use
dysrhythmia Check expiration
● Headache, Insomnia, N/V/D Listen to lung sounds
ADRENERGIC AGONIST: CLONIDINE
Action Uses
9/28/21 PHARM ADRENERGIC AGONISTS AND ANTAGONISTS
Adrenergic Agonists & Antagonists
Readings
● Chapter #15
McCuiston, L.E., Vuljoin-DiMaggio, K., Winton, M., & Yeager, J.J. (2021) Pharmacology: A
patient-centered nursing process approach (10th ed.). Canada: Saunders/Elsevier Inc.
The Nervous System
The Sympathetic Nervous System / adrenergic nervous system
o (arousing)
● “Fight or Flight” Response
○ Effects on the body
● Neurotransmitters
○ Epinephrine, Dopamine, Norepinephrine → catecholamines
○ Endogenous or exogenous (synthetic)
● Adrenergic receptors
ADRENERGIC RECEPTORS
Alpha1 (ɑ1) Beta1 (�1)
● Blood vessels→ vasoconstriction, ● Heart: increased heart contraction,
increase BP, increased contractility of increased HR
the heart ● Kidney: increased renin secretion,
● Eye → mydriasis(pupil dilation) increased angiotensin, increased blood
● Bladder → relax pressure
● Prostatic → contraction
Alpha2 (ɑ2) Beta1 (�2)
● Blood vessels → decrease blood ● Smooth muscle (GI) → decreased GI
pressure motility and tone
● Smooth muscle (GI tract) → decrease ● Lungs → bronchodilation
GI motility and tone ● Uterus → relaxation of uterine smooth
muscle
● Liver → activation of glycogenolysis,
increased blood sugar
Dopaminergic Receptors
● Located in renal, mesenteric, coronary, and cerebral arteries
● Causes vasodilation and increased blood flow
● _______________ is the only neurotransmitter medication that can activate this receptor
Adrenergic Medications
Adrenergic Agonists
● AKA: sympathomimetics
● Stimulate the sympathetic nervous system because they __________ endogenous
sympathetic neurotransmitters
● Act on adrenergic receptors at target sites
● Classifications
● Direct Acting
○ Epinephrine (Epi) and norepinephrine (NE)
, 2
9/28/21 PHARM ADRENERGIC AGONISTS AND ANTAGONISTS
○ Directly stimulates adrenergic receptors
● Indirect Acting
○ Amphetamine
○ Stimulates the release of NE from terminal nerve endings
● Mixed Acting
○ Ephedrine and pseudoephedrine
○ Stimulates adrenergic receptor sites and stimulates the release of NE from
terminal nerve endings
● selective vs. non-selective
○ Target organs
Epinephrine: Adrenergic Agonists
Action Uses
● Potent inotrope → vasocontriction and ● Anaphylaxis
bronchodilation ● Bronchospasms, status asthmaticus
● Non-selective adrenergic agonist ● Cardiogenic shock, cardiac arrest
● Given IV, IM, or ET
Side Effects/Adverse Reactions Contraindications
● Tachycardia, dysrhythmias, ● Use with caution in pt taking Digoxin
palpitations → dysrhythmia
● Hypertension, headache, dizziness ● Tricyclic Antidepressants &
● Insomnia, restlessness, tremors monoamine oxidase inhibitors →
intensive and prolong effects of epi
● Beta blockers → antagonistic effect
Nursing Interventions
● Obtain and record vital signs (BP & HR)
● Monitor urine output & IV site for infiltration
● Report rhythm tremors, dizziness, HTN, and palpitations
● Avoid cold medicines and diet pills if hypertensive
● Antidote: phentolamine mesylate
ALBUTEROL: ADRENERGIC AGONIST
Action Uses
● Selective (�2) ● Asthma → emergency and
● Bronchodilation bronchospasm prophylaxis
Side Effects/Adverse Drug Reactions Nursing interventions
● Tremor, nervousness, anxiety Teach pt. how to use, rinse mouth
● Tachycardia, hypertension, after use
dysrhythmia Check expiration
● Headache, Insomnia, N/V/D Listen to lung sounds
ADRENERGIC AGONIST: CLONIDINE
Action Uses
