Adrenergic Antagonists (Sympatholytics) Nursing Pharmacology Study Guides

Adrenergic antagonists are also referred to as sympatholytics because they lyse, or block, the effects of the sympathetic nervous system. They react with specific adrenergic receptor sites without activating them, thus preventing the typical manifestations of SNS activation.

These drugs occupy the adrenergic receptor site so released norepinephrine can be prevented from activating the receptor.

Adrenergic antagonists have varying degrees of specificity and are therefore classified into five: nonselective adrenergic antagonists, nonselective alpha- and beta- adrenergic antagonists, and selective alpha1– and beta-adrenergic antagonists.

Table of Common Drugs and Generic Names


Here is a table of commonly encountered adrenergic antagonists, their generic names, and brand names:

Classification Generic Name Brand Name
Nonselective Adrenergic Blocking Agents amiodarone Cordarone
carvedilol Coreg
labetalol Normodyne, Trandate
Nonselective Alpha-Adrenergic Blocking Agent phentolamine Regitine
Alpha1-Selective Adrenergic Blocking Agents alfuzosin Uroxatral
doxazosin Cardura
prazosin Minipress
tamsulosin Flomax
terazosin Hytrin
Nonselective Beta-Adrenergic Blocking Agents nebivolol Bystolic
nadolol Corgard
propranolol Inderal
timolol Blocarden, Timoptic
Beta1-Selective Adrenergic Blocking Agents bisoprolol Zebeta
esmolol Brevibloc
metoprolol Lopressor, Toprol XL

Disease Spotlight: Cardiorespiratory-related conditions, Benign Prostatic Hypertrophy


  • Nonselective adrenergic antagonists are primarily used to treat cardiac-related conditions. Completely opposite with sympathomimetics, these drugs are ideal for hypertension and heart failure because they reduce the rate and conduction of the heart, relieving it from too much workload.
  • Of all nonselective alpha adrenergic antagonists, only phentolamine (Regitine) is used. This drug classification has its use limited because of more specific drugs.
  • Selective alpha1-receptor adrenergic antagonists can improve urine flow in male patients and are used as treatment for benign prostatic hypertrophy (BPH). This is because they can block smooth muscle receptors in the genitourinary tract which leads to relaxation of prostate and bladder.
  • Nonselective beta-adrenergic antagonists are used to treat CV problems and to prevent reinfarction after MI.
  • Selective beta1-receptor adrenergic antagonists is more advantageous than nonselective beta-blockers because they don’t block beta2-receptors, allowing bronchodilation. This class is preferred for smokers and those with respiratory problems. They are also used for treating hypertension, angina, and cardiac arrhythmias.

Nonselective Adrenergic Blocking Agents


Description

  • Nonselective adrenergic blocking agents block all receptors (alpha- and beta-receptors). These drugs are primarily used to treat cardiac-related conditions.
  • Popular example under this class include labetalol and carvedilol.

Therapeutic Action

The desired and beneficial actions of nonselective adrenergic antagonists are as follows:

  • Nonselective adrenergic antagonists competitively block the effects of norepinephrine at both alpha and beta receptors throughout the SNS. This results in lower blood pressure, slower pulse rate, and increased renal perfusion with decreased renin levels.

Indications

Nonselective adrenergic antagonists are indicated for the following medical conditions:

  • Most nonselective adrenergic antagonists  (e.g. labetalol, carvedilol, etc.) are indicated to treat essential hypertension, alone or in combination with diuretics. Others (e.g. amiodarone) is for emergency cases and is only used as an antiarrhythmic.

Here are some important aspects to remember for indication of adrenergic antagonists in different age groups:

Children

  • They are at greater risk for complications related to use of these drugs, i.e. bradycardia, difficulty breathing, and changes in glucose metabolism.
  • Safety of these drugs has not been established in children younger than 18. However, three drugs have established pediatric dosage. Prazosin (for treatment of hypertension) and phentolamine (used during surgery for pheochromocytoma) are two of these drugs.

Adults

  • Adults with diabetes should be monitored closely for fluctuations in glucose levels because sympathetic reactions (e.g. sweating, feeling tense, increased heart rate, and rapid breathing) can cause problems with glucose levels.
  • Adults with CNS complications may benefit from adrenergic antagonists which are not centrally-acting.
  • Use of these drugs among pregnant and lactating women is justified when benefits clearly outweigh the risks.

Older adults

  • Dose adjustment is needed as this age group is also more susceptible to drug side effects.
  • They are more likely to have toxic levels of the drug because of renal or hepatic impairments.
  • Bisoprolol is the drug of choice for older patients in treating hypertension because it is not associated with as many problems and regular dosing profiles can be used.

Pharmacokinetics

Here are the characteristic interactions of nonselective adrenergic antagonists and the body in terms of absorption, distribution, metabolism, and excretion:

Route Onset Peak Duration
Oral Varies 1-2 h 8-12 h
IM Immediate 5 min 5.5 h
T1/2: 6-8 h
Metabolism: liver
Excretion: urine

Contraindications and Cautions

The following are contraindications and cautions for the use of nonselective adrenergic antagonists:

  • Allergy to any component of the drug. To prevent hypersensitivity reaction
  • Bradycardia and heart blocks. Can be worsened by slowed heart rate and conduction.
  • Hepatic impairment. Can alter metabolism of drugs.
  • Asthma. Exacerbated by loss of norepinephrine’s effect of bronchodilation.
  • Shock or heart failure. Can become worse with loss of sympathetic reaction
  • Lactation. Potential effects on neonates.

Adverse Effects

Use of nonselective adrenergic antagonists may result to these adverse effects:

  • CNS: dizziness, paresthesias, insomnia, depression, fatigue, vertigo
  • CV: arrhythmias, hypotension, heart failure, pulmonary edema, CVA
  • Respiratory: bronchospasms, cough, rhinitis, bronchial obstruction
  • GI: nausea, vomiting, diarrhea, anorexia, flatulence
  • GU: decreased libido, impotence, dysuria, Peyronie disease.
  • Others: decreased exercise tolerance, hypoglycemia, rash
  • Carvedilol has been associated with hepatic failure related to its effects on the liver.
  • Abrupt withdrawal: MI, stroke, arrhythmias related to increased hypersensitivity to catecholamines that develops when the receptor sites have been blocked.

Interactions

The following are drug-drug interactions involved in the use of nonselective adrenergic antagonists:

Nursing Considerations

Here are important nursing considerations when administering nonselective adrenergic antagonists:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

  • Assess for contraindications or cautions (e.g. history of allergy to drug, heart blocks, asthma, pregnancy or lactation status, etc.) to avoid adverse effects.
  • Establish baseline physical assessment to monitor for any potential adverse effects.
  • Assess the level of orientation and for any complaints of dizziness, paresthesias, or vertigo to monitor CNS drug effects.
  • Assess vital signs, especially pulse and blood pressure to monitor for possible excess stimulation of the cardiac system.
  • Note respiratory rate and auscultate lungs for adventitious sounds to evaluate effects on bronchi and respirations.
  • Monitor laboratory test results (e.g. liver and renal function tests) to determine need for possible dose adjustment, serum electrolyte levels to evaluate fluid loss and appropriateness of therapy, and blood glucose to evaluate for hyper- or hypoglycemia.
Nursing Diagnoses

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

Implementation with Rationale

These are vital nursing interventions done in patients who are taking nonselective adrenergic antagonists:

  • Do not discontinue abruptly after chronic therapy because hypersensitivity to catecholamines may develop and patient could have severe reaction; taper drug slowly over two weeks, monitoring the patient.
  • Educate patient about positive lifestyle changes (e.g. diet, exercise, smoking cessation) to aid in lowering blood pressure.
  • Assess heart rate for changes that might suggest arrhythmia. Obtain blood pressure in various positions to assess for orthostatic hypotension.
  • Monitor GI function and need for increased access to bathroom facilities and need for increased fluid intake related to diarrhea.
  • Provide comfort measures to help patient cope with drug effects.
  • Provide patient education about drug effects and warning signs to report to enhance knowledge about drug therapy and promote compliance.
Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

  • Monitor patient response to therapy (improvement in blood pressure and heart failure).
  • Monitor for adverse effects (e.g. CV changes, headache, GI upset, liver failure).
  • Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
  • Monitor patient compliance to drug therapy.

Nonselective Alpha-Adrenergic Blocking Agents


Description

  • Nonselective alpha-adrenergic blocking agents are drugs with specific affinity for alpha-receptor sites. Their use has somewhat limited because of development of more specific and safer drugs.
  • Of all drugs, only phentolamine is still used.

Therapeutic Action

The desired and beneficial actions of nonselective alpha-adrenergic antagonists are as follows:

  • Phentolamine blocks the alpha1-adrenergic receptors, decreasing sympathetic tone in the vasculature and causing vasodilation, which leads to lowering of blood pressure.
  • It also blocks the alpha2-receptors, preventing the feedback control of norepinephrine release. The result is an increase in reflex tachycardia that occurs when blood pressure is lowered.

Indications

Nonselective alpha-adrenergic antagonists are indicated for the following medical conditions:

  • Phentolamine is most frequently used to prevent cell death and tissue sloughing after extravasation of intravenous norepinephrine or dopamine, causing a local vasodilation and a return of blood flow to the area.
  • For treatment of severe hypertension reactions caused by manipulation of pheochromocytoma before and during surgery
  • For diagnosis of pheochromocytoma

Pharmacokinetics

Here are the characteristic interactions of nonselective alpha-adrenergic antagonists and the body in terms of absorption, distribution, metabolism, and excretion:

Route Onset Peak Duration
IM Rapid 20 min 30-45 min
IV Immediate 2 min 15-30 min
T1/2: Unknown
Metabolism: Unknown
Excretion: Unknown

Contraindications and Cautions

The following are contraindications and cautions for the use of nonselective alpha-adrenergic antagonists:

  • Allergy to any component of the drug. To prevent hypersensitivity reaction
  • Coronary artery disease or MI. Potential exacerbation of these conditions.
  • Pregnancy and lactation. Potential effects to  fetus or neonates.

Adverse Effects

Use of nonselective alpha-adrenergic antagonists may result to these adverse effects:

Interactions

The following are drug-drug interactions involved in the use of nonselective alpha-adrenergic antagonists:

Nursing Considerations

Here are important nursing considerations when administering nonselective alpha-adrenergic antagonists:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

  • Assess for contraindications or cautions (e.g. history of allergy to drug, CV diseases, pregnancy or lactation status, etc.) to avoid adverse effects.
  • Establish baseline physical assessment to monitor for any potential adverse effects.
  • Assess orientation, affect, and reflexes to monitor for CNS changes related to drug therapy.
  • Monitor CV status (blood pressure, pulse rate, peripheral perfusion) to determine changes in function.
  • Monitor urine output which will reflect perfusion of the kidney as another assessment of cardiac function.
Nursing Diagnoses

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

Implementation with Rationale

These are vital nursing interventions done in patients who are taking nonselective alpha-adrenergic antagonists:

  • Monitor heart rate and blood pressure closely and frequently for changes to anticipate the need to discontinue the drug if adverse reactions are severe.
  • Inject phentolamine directly into area of extravasation of epinephrine or dopamine to prevent local cell death.
  • Institute safety measures to prevent injury if the patient experiences weakness, dizziness, or orthostatic hypotension.
  • Provide comfort measures to help patient cope with drug effects.
  • Provide patient education about drug effects and warning signs to report to enhance knowledge about drug therapy and promote compliance.
Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

  • Monitor patient response to therapy (improvement in signs and symptoms of pheochromocytoma, improvement in tissue condition after extravasation).
  • Monitor for adverse effects (e.g. orthostatic hypotension, arrhythmias, CNS effects).
  • Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
  • Monitor patient compliance to drug therapy.

Alpha1-Selective Adrenergic Blocking Agents

Description
  • Alpha1-selective adrenergic blocking agents are drugs that have a specific affinity for alpha1-receptors.
  • Common drug examples include prazosin, tamsulosin, and doxazosin.
Therapeutic Action

The desired and beneficial actions of alpha1-selective adrenergic blocking agents are as follows:

  • Blocking the postsynaptic alpha1-receptor sites. This causes a decrease in vascular tone and vasodilation, which leads to a fall in blood pressure. A reflex tachycardia that accompanies a fall in blood pressure does not occur because they do not block presynaptic alpha2-receptor sites.
  • Reducing total peripheral resistance through alpha blockade; it does not affect heart rate or cardiac output.
  • Increasing high-density lipoproteins while lowering total cholesterol level.
  • Blocking smooth muscle receptors in prostate, prostatic capsule, prostatic urethra, and urinary bladder neck leading to relaxation of bladder and prostate and improved flow of urine in male patients.
Indications

Alpha1-selective adrenergic blocking agents are indicated for the following medical conditions:

Pharmacokinetics

Here are the characteristic interactions of alpha1-selective adrenergic blocking agents and the body in terms of absorption, distribution, metabolism, and excretion:

Route Onset Peak Duration
Oral Varies 2-3 h Not known
T1/2: 22 hours
Metabolism: liver
Excretion: bile, feces, urine
Contraindications and Cautions

The following are contraindications and cautions for the use of alpha1-selective adrenergic blocking agents:

  • Allergy to any component of the drug. To prevent hypersensitivity reaction
  • Lactation. Drugs cross into breast milk
  • Heart or renal failure. Can be exacerbated by blood pressure-lowering effects of the drug
  • Hepatic impairment. Can alter drug metabolism.
  • Pregnancy. Potential adverse effects to the fetus.
Adverse Effects

Use of alpha1-selective adrenergic blocking agents may result to these adverse effects:

  • CNS: headache, weakness, dizziness, fatigue, drowsiness, depression
  • CV: arrhythmia, hypotension, edema, HF, angina
  • GI: nausea, vomiting, diarrhea, abdominal pain
  • Vasodilation drug effect: flushing, rhinitis, reddened eyes, nasal congestion, priapism
Interactions

The following are drug-drug interactions involved in the use of alpha1-selective adrenergic blocking agents:

Nursing Considerations

Here are important nursing considerations when administering alpha1-selective adrenergic blocking agents:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

  • Assess for contraindications or cautions (e.g. history of allergy to drug, heart or renal failure, pregnancy or lactation status, etc.) to avoid adverse effects.
  • Establish baseline physical assessment to monitor for any potential adverse effects.
  • Assess orientation, affect, and reflexes to monitor for CNS changes related to drug therapy.
  • Monitor CV status (blood pressure, pulse rate, peripheral perfusion) to determine changes in function.
  • Assess renal function, including urinary output, to evaluate effects on the renal system and assess benign prostatic hypertrophy and its effects on urinary output.
  • Monitor renal and hepatic function tests to evaluate potential need for dose adjustment.
Nursing Diagnoses

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

Implementation with Rationale

These are vital nursing interventions done in patients who are taking alpha1-selective adrenergic blocking agents:

  • Monitor blood pressure, pulse, rhythm, and cardiac output regularly to evaluate for changes that may indicate a need to adjust dose or discontinue the drug if CV effects are severe.
  • Establish safety precautions if CNS effects or orthostatic hypotension occurs to prevent patient injury.
  • Arrange for small, frequent meals if GI upset is severe to relieve discomfort and maintain nutrition.
  • Provide comfort measures to help patient cope with drug effects.
  • Provide patient education about drug effects and warning signs to report to enhance knowledge about drug therapy and promote compliance.
Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

  • Monitor patient response to therapy (lowering of blood pressure, improved urine flow with BPH).
  • Monitor for adverse effects (e.g. GI upset, CNS, or CV changes).
  • Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
  • Monitor patient compliance to drug therapy.

Nonselective Beta-Adrenergic Blocking Agents

Description

  • Nonselective beta-adrenergic blocking agents are drugs that block the beta-receptors within the SNS. Nonselective blockade of all beta-receptors results in a loss of the reflex bronchodilation that occurs with sympathetic stimulation.
  • Use of these drugs is limited in patients who smoke or have allergic or seasonal rhinitis, asthma, or COPD.
  • Common drug examples include propranolol, nebivolol, and timolol.

Therapeutic Action

The desired and beneficial actions of nonselective beta-adrenergic blocking agents are as follows:

  • Competitively blocks beta-adrenergic receptors in the heart and juxtaglomerular apparatus
  • Reduction of vascular tone in the CNS

Indications

Nonselective beta-adrenergic blocking agents are indicated for the following medical conditions:

  • These drugs are used for a wide range of conditions, including hypertension, stage fright (situational anxiety), migraines, angina, and essential tremors.
  • Timolol and carteolol in ophthalmic form are used for reduction of intraocular pressure in patients with open-angle glaucoma.

Pharmacokinetics

Here are the characteristic interactions of nonselective beta-adrenergic blocking agents and the body in terms of absorption, distribution, metabolism, and excretion:

Route Onset Peak Duration
Oral 20-30 min 60-90 min 6-12 h
IV Immediate 1 min 4-6 h
T1/2: 3-5 hours
Metabolism: liver
Excretion: urine

Contraindications and Cautions

The following are contraindications and cautions for the use of nonselective beta-adrenergic blocking agents:

  • Allergy to any component of the drug. To prevent hypersensitivity reaction
  • Bradycardia, heart blocks, shock, HF. Can be exacerbated by the cardiac-suppressing effects of these drugs
  • Bronchospasm, COPD, acute asthma. Can be worsen due to blocking of the sympathetic bronchodilation
  • Pregnancy. Teratogenic effects have occurred in animal studies with all these drugs except sotalol; neonatal apnea, bradycardia, and hypoglycemia can occur
  • Lactation. Potential effects to the neonate include slowed heart rate, hypotension, and hypoglycemia
  • Diabetes, hypoglycemia. Drugs can block the normal signs and symptoms of hypo- and hyperglycemia
  • Thyrotoxicosis. Adrenergic blocking effects on the thyroid gland
  • Renal or hepatic dysfunction. Can interfere with drug metabolism and excretion.

Adverse Effects

Use of nonselective beta-adrenergic blocking agents may result to these adverse effects:

  • CNS: headache, fatigue, dizziness, depression, paresthesia, sleep disturbances, memory loss, disorientation
  • CV: bradycardia, heart block, HF, hypotension, peripheral vascular insufficiency
  • Respiratory: difficulty of breathing, coughing, bronchospasm, severe pulmonary edema, severe bronchial obstruction
  • GI: GI upset, nausea, vomiting, diarrhea, gastric pain, colitis
  • GU: decreased libido, impotence, dysuria, Peyronie disease
  • Other: decreased exercise tolerance, hypo- or hyperglycemia, liver changes
  • Abrupt withdrawal: angina, MI, hypertension, stroke

Interactions

The following are drug-drug interactions involved in the use of nonselective beta-adrenergic blocking agents:

  • Clonidine. Paradoxical hypertension can occur; increased rebound hypertension with clonidine withdrawal.
  • NSAIDs. Decreased antihypertensive effect
  • Epinephrine. Initial hypertensive episode followed by bradycardia
  • Ergot alkaloids. Peripheral ischemia may occur
  • Insulin and other antidiabetic agents. Potential change in blood glucose levels

Nursing Considerations

Here are important nursing considerations when administering nonselective beta-adrenergic blocking agents:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

  • Assess for contraindications or cautions (e.g. history of allergy to drug, heart failure, pregnancy or lactation status, etc.) to avoid adverse effects.
  • Establish baseline physical assessment to monitor for any potential adverse effects.
  • Assess orientation, affect, and reflexes to monitor for CNS changes related to drug therapy.
  • Monitor CV status (blood pressure, pulse rate, peripheral perfusion) to determine changes in function.
  • Assess abdomen, including auscultating bowel sounds to monitor GI effects.
  • Monitor renal and hepatic function tests to evaluate potential need for dose adjustment, as well as electrolyte levels to monitor for risks for arrhythmias.
Nursing Diagnoses

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

Implementation with Rationale

These are vital nursing interventions done in patients who are taking nonselective beta-adrenergic blocking agents:

  • Do not stop these drugs abruptly after chronic therapy, but taper gradually over 2 weeks because long-term use of these drugs can sensitize the myocardium to catecholamines, and severe reactions could occur.
  • Continuously monitor any patient receiving an intravenous form of these drugs to avert serious complications caused by rapid sympathetic blockade.
  • Provide comfort measures to help patient cope with drug effects.
  • Provide patient education about drug effects and warning signs to report to enhance knowledge about drug therapy and promote compliance.
Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

  • Monitor patient response to therapy (lowering of blood pressure, decrease in angina episodes, and improvement of condition being treated).
  • Monitor for adverse effects (e.g. GI upset, CNS, or CV changes).
  • Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
  • Monitor patient compliance to drug therapy.

Beta1-Selective Adrenergic Blocking Agents

Description

  • Beta1-selective adrenergic blocking agents are drugs that do not block the beta1-receptors responsible for bronchodilation. This gives them an advantage over nonselective beta-blockers.
  • These drugs are preferred for patients who smoke or who have asthma, any other obstructive pulmonary disease, or seasonal or allergic rhinitis.
  • Popular examples under this class include atenolol, metoprolol, and esmolol.

Therapeutic Action

The desired and beneficial actions of beta1-selective adrenergic blocking agents are as follows:

  • Blocking the beta1-adrenergic receptors decreasing the excitability of the heart, cardiac output, and oxygen consumption.
  • Decreasing renin release which lowers blood pressure.

Indications

Nonselective beta-adrenergic blocking agents are indicated for the following medical conditions:

  • Treatment for cardiac arrhythmias, hypertension, and chronic angina
  • Prevention of reinfarction after an MI by decreasing cardiac workload and oxygen consumption
  • In oral form, used to decrease intraocular pressure and to treat open-angle glaucoma

Pharmacokinetics

Here are the characteristic interactions of beta1-selective adrenergic blocking agents and the body in terms of absorption, distribution, metabolism, and excretion:

Route Onset Peak Duration
Oral Varies 2-4 h 24 h
IV Immediate 5 min 24 h
T1/2: 6-7 h
Metabolism: –
Excretion: bile, urine, feces

Contraindications and Cautions

The following are contraindications and cautions for the use of beta1-selective adrenergic blocking agents:

  • Allergy to any component of the drug. To prevent hypersensitivity reaction
  • Bradycardia, heart blocks, cardiogenic shock, HF. Can be exacerbated by the cardiac-suppressing effects of these drugs
  • Pregnancy and lactation. Potential effects to the fetus or neonate
  • Diabetes, thyrotoxicosis, COPD. Potential for adverse effects on these diseases with sympathetic blockade

Adverse Effects

Use of beta1-selective adrenergic blocking agents may result to these adverse effects:

  • CNS: headache, fatigue, dizziness, depression, paresthesia, sleep disturbances, memory loss, disorientation
  • CV: bradycardia, heart block, HF, hypotension, peripheral vascular insufficiency
  • Respiratory: rhinitis, bronchospasm, dyspnea
  • GI: GI upset, nausea, vomiting, diarrhea, gastric pain, colitis
  • GU: decreased libido, impotence, dysuria, Peyronie disease
  • Other: decreased exercise tolerance, hypo- or hyperglycemia, liver changes
  • Abrupt withdrawal: angina, MI, hypertension, stroke

Interactions

The following are drug-drug interactions involved in the use of beta1-selective adrenergic blocking agents:

Nursing Considerations

Here are important nursing considerations when administering beta1-selective adrenergic blocking agents:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

  • Assess for contraindications or cautions (e.g. history of allergy to drug, bradycardia, pregnancy or lactation status, etc.) to avoid adverse effects.
  • Establish baseline physical assessment to monitor for any potential adverse effects.
  • Assess orientation, affect, and reflexes to monitor for CNS changes related to drug therapy.
  • Monitor CV status (blood pressure, pulse rate, peripheral perfusion) to determine changes in function.
  • Assess abdomen, including auscultating bowel sounds to monitor GI effects.
  • Monitor renal and hepatic function tests to evaluate potential need for dose adjustment, as well as electrolyte levels to monitor for risks for arrhythmias.
Nursing Diagnoses

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

Implementation with Rationale

These are vital nursing interventions done in patients who are taking beta1-selective adrenergic blocking agents:

  • Do not stop these drugs abruptly after chronic therapy, but taper gradually over 2 weeks because long-term use of these drugs can sensitize the myocardium to catecholamines, and severe reactions could occur.
  • Continuously monitor any patient receiving an intravenous form of these drugs to avert serious complications caused by rapid sympathetic blockade.
  • Give oral forms of metoprolol with food to facilitate absorption.
  • Provide comfort measures to help patient cope with drug effects.
  • Provide patient education about drug effects and warning signs to report to enhance knowledge about drug therapy and promote compliance.
Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

  • Monitor patient response to therapy (lowered blood pressure, fewer angina episodes, lowered intraocular pressure).
  • Monitor for adverse effects (e.g. GI upset, CNS, or CV changes).
  • Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
  • Monitor patient compliance to drug therapy.

Practice Quiz: Adrenergic Antagonists


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Practice Quiz: Adrenergic Antagonists (Sympaptholytics)

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1. Student Nurse Aimee is reviewing for her licensure exam. She would be right to pick which drug pairing (classification and corresponding example)?

A. alpha1-selective adrenergic blocking agent: phentolamine
B. nonselective adrenergic blocking agent: labetalol
C. nonselective alpha-adrenergic blocking agent: doxazosin
D. nonselective beta-adrenergic blocking agent: metoprolol

1. Answer: B. nonselective adrenergic blocking agent: labetalol

Other examples of nonselective adrenergic blocking agents aside from labetalol are amiodarone and carvedilol. Phentolamine is a nonselective alpha blocker. Doxazosin is an alpha1-selective blocker and metoprolol is a selective beta-blocker.

2. Which of the following drugs can improve urine flow in males?

A. prazosin
B. nebivolol
C. labetalol
D. amiodarone

2. Answer: A. prazosin

Prazosin, a selective alpha1-receptor adrenergic antagonist, can improve urine flow in male patients and are used as treatment for benign prostatic hypertrophy (BPH). This is because they can block smooth muscle receptors in the genitourinary tract which leads to relaxation of prostate and bladder.

3. Nurse Sam is taking care of a patient on carvedilol therapy. Which parameter should he monitor regularly to assess for possible dose adjustment?

A. serum sodium level
B. hemoglobin and hematocrit
C. SGPT
D. BUN

3. Answer: C. SGPT

Carvedilol has been associated with hepatic failure related to its effects on the liver.

4. Mrs. Smith, a 40-year-old patient, came in due to acute hypertensive episode. Her chart says she is asthmatic. Which of the following drugs would be safest to give?

A. nebivolol
B. timolol
C. propranolol
D. atenolol

4. Answer: D. atenolol

Atenolol is a selective beta-blocker and it does not block the receptors responsible for bronchodilation. All other options are nonselective beta-blockers and may cause bronchoconstriction and spasms.

5. Which of the following drug is used for diagnosis of pheochromocytoma?

A. amiodarone
B. phentolamine
C. tamsulosin
D. acebutolol

5. Answer: B. phentolamine

See Also


Here are other nursing pharmacology study guides: Endocrine System Drugs Autonomic Nervous System Drugs Immune System Drugs Chemotherapeutic Agents Reproductive System Drugs Nervous System Drugs Cardiovascular System Drugs

Further Reading and Resources


Recommended resources and books:
  1. Focus on Nursing Pharmacology - Easy to follow guide for Pharmacology
  2. NCLEX-RN Drug Guide: 300 Medications You Need to Know for the Exam - Great if you're reviewing for the NCLEX
  3. Nursing 2017 Drug Handbook (Nursing Drug Handbook) - Reliable nursing drug handbook!
  4. Lehne's Pharmacology for Nursing Care - Provides key information on commonly used drugs in nursing
  5. Pharmacology and the Nursing Process - Learn how to administer drugs correctly and safely!
  6. Pharm Phlash Cards!: Pharmacology Flash Cards - Flash Cards for Nursing Pharmacology
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