Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CHAPTER 19 Adrenergic-Blocking Drugs

2 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic Blockers  Bind to adrenergic receptors, but inhibit or block stimulation of the sympathetic nervous system (SNS)  Alpha-blockers and beta-blockers

3 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic Blockers (cont’d)  Have the opposite effect of adrenergic drugs  Inhibit—or lyse—sympathetic stimulation  Also known as:  Adrenergic antagonists  Sympatholytics  Alpha-blockers, beta-blockers, or alpha-beta blockers

4 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic Blockers (cont’d)  Classified by the type of adrenergic receptor they block  Alpha 1 and alpha 2 receptors  Beta 1 and beta 2 receptors

5 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

6 Drug Effects and Indications: Alpha-Blockers  Cause both arterial and venous dilation, reducing peripheral vascular resistance and BP  Used to treat hypertension  Effect on receptors on prostate gland and bladder decreases resistance to urinary outflow, thus reducing urinary obstruction and relieving effects of BPH

7 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Drug Effects and Indications: Alpha-Blockers (cont’d)  Used to control and prevent hypertension in patients with pheochromocytoma  Phentolamine  Quickly reverses the potent vasoconstrictive effects of extravasated vasopressors such as norepinephrine or epinephrine  Restores blood flow and prevents tissue necrosis

8 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Alpha-Blockers: Adverse Effects Body SystemAdverse Effects CardiovascularPalpitations, orthostatic hypotension, tachycardia, edema, dysrhythmias, chest pain CNSDizziness, headache, drowsiness, anxiety, depression, vertigo, weakness, numbness, fatigue

9 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Alpha-Blockers: Adverse Effects (cont’d) Body SystemAdverse Effects GastrointestinalNausea, vomiting, diarrhea, constipation, abdominal pain OtherIncontinence, nosebleed, tinnitus, dry mouth, pharyngitis, rhinitis

10 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Common Alpha-Blockers  phenoxybenzamine HCl (Dibenzyline)  phentolamine (Regitine)  prazosin (Minipress)  tolazoline (Priscoline)

11 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Blockers  Block stimulation of beta receptors in the SNS  Compete with norepinephrine and epinephrine  Can be selective or nonselective  Nonselective beta-blockers block both beta 1 and beta 2 receptors

12 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta Receptors  Beta 1 receptors  Located primarily on the heart  Beta-blockers selective for these receptors are called cardioselective beta-blockers  Beta 2 receptors  Located primarily on smooth muscle of bronchioles and blood vessels

13 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Mechanism of Action  Cardioselective beta-blockers (beta 1 )  Reduce SNS stimulation of the heart  Decrease heart rate  Prolong SA node recovery  Slow conduction rate through the AV node  Decrease myocardial contractility, thus reducing myocardial oxygen demand

14 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Mechanism of Action (cont’d)  Nonselective beta-blockers (beta 1 and beta 2 )  Cause same effects on heart as cardioselective beta-blockers  Constrict bronchioles, resulting in narrowing of airways and shortness of breath  Produce vasoconstriction of blood vessels  Other effects

15 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Indications  Angina  Decreases demand for myocardial oxygen  Cardioprotective  Inhibits stimulation from circulating catecholamines  Dysrhythmias  Class II antidysrhythmic  Migraine headache  Lipophilicity allows entry into CNS

16 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Indications (cont’d)  Antihypertensive  Heart failure  Glaucoma (topical use)

17 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adverse Effects: Beta-Blockers Body SystemAdverse Effects BloodAgranulocytosis, thrombocytopenia CardiovascularAV block, bradycardia, heart failure, peripheral vascular insufficiency CNSDizziness, mental depression, lethargy, hallucinations, unusual dreams

18 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adverse Effects: Beta-Blockers Body SystemAdverse Effects GastrointestinalNausea, dry mouth, vomiting, diarrhea, cramps, ischemic colitis OtherImpotence, rash, alopecia, bronchospasm

19 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adverse Effects: Beta-Blockers  Nonselective beta-blockers may interfere with normal responses to hypoglycemia (tremor, tachycardia, nervousness)  May mask signs and symptoms of hypoglycemia

20 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Blockers: Examples  acebutolol (Sectral)  carvedilol (Coreg)  labetalol (Normodyne)  metoprolol (Lopressor)  atenolol (Tenormin)  esmolol (Brevibloc)  sotalol (Betapace)  propranolol (Inderal)

21 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic-Blocking Drugs: Nursing Implications  Assess for allergies and history of COPD, hypotension, cardiac dysrhythmias, bradycardia, heart failure, or other cardiovascular problems  Any preexisting condition that might be exacerbated by the use of these drugs might be a contraindication to their use

22 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic-Blocking Drugs: Nursing Implications (cont’d)  Remember that alpha-blockers may precipitate hypotension  Remember that some beta-blockers may precipitate bradycardia, hypotension, heart block, heart failure, and bronchoconstriction

23 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic-Blocking Drugs: Nursing Implications (cont’d)  Avoid over-the-counter medications because of possible interactions  Possible drug interactions may occur with:  Antacids (aluminum hydroxide type)  Antimuscarinics/anticholinergics  Diuretics and cardiovascular drugs  Neuromuscular blocking drugs  Oral hypoglycemic drugs

24 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic-Blocking Drugs: Nursing Implications (cont’d)  Encourage patients to take medications as prescribed  Instruct patients that these medications should never be stopped abruptly  Inform patients to report constipation or the development of urinary hesitancy or bladder distention

25 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic-Blocking Drugs: Nursing Implications (cont’d)  Teach patients to change positions slowly to prevent or minimize postural hypotension  Instruct patients to avoid caffeine (excessive irritability)  Instruct patients to avoid alcohol ingestion and hazardous activities until blood levels become stable  Instruct patients to notify their physician if palpitations, dyspnea, nausea, or vomiting occurs

26 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic-Blocking Drugs: Nursing Implications (cont’d)  Monitor for adverse effects  Monitor for therapeutic effects  Decreased chest pain in patients with angina  Return to normal BP and HR  Other specific effects, depending on the use

27 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Blocking Drugs: Nursing Implications  Rebound hypertension or chest pain may occur if this medication is discontinued abruptly  Instruct patients to notify their physician if they become ill and unable to take medication  Inform patients that they may notice a decrease in tolerance for exercise (dizziness and fainting may occur with increased activity), and have patients notify the physician if these problems occur

28 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Blocking Drugs: Nursing Implications (cont’d)  Inform patients to report the following to their physician:  Weight gain of more than 2 pounds in 1 day or 5 pounds in 1 week  Edema of the feet or ankles  Shortness of breath  Excessive fatigue or weakness  Syncope or dizziness