NURS 1950: Pharmacology I 1

 Objective 1: describe the relationship of calcium to electrical activity of the heart  Resting:  Preload:  Afterload: 2

 Heart dependent upon influx of calcium  Ca+ enters channels in the cardiac cell membrane and go into the cell along with Na  K+ comes out  Cardiac cells contract 3

 Objective 2: describe how the ANS affects the heart rate 4

 The ANS is the primary controller of heart rate  Cholinergic (parasympathetic) vagal fibers are close to the SA node  Stimulation with acetylcholine slows the heart rate 5

 Sympathetic (adrenergic) nerves also innervate the heart  Stimulation causes norepinephrine to be released.  Increases heart rate, slows refractory period 6

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 Objective 3: describe how cardiac drugs affect cardiac action 8

 1. Increase or decrease the force of myocardial action  Positive inotropics  Negative inotropics 9

 2. Increase or decrease heart rate by altering SA node impulse conduction  Positive chronotropics  Negative chronotropics 10

 3. Increase or decrease conduction of AV impulses  Positive dromotropics  Negative dromotropics 11

 Diuretics to decrease blood volume 12

 Objective 4: identify the action of cardiac glycosides 13

 Digoxin & relatives come from  Natural sources  Helpful in CHF  Have a positive inotropic effect 14

 Increases mechanical efficiency of heart  This pumps more blood  With increased blood to kidneys, diuresis occurs, edema reduced  Cardiac glycosides also have negative chronotropic effect,  Negative dromotropic effect 15

 Action  Thought that they cause release of free calcium within the cardiac muscle cell  Also change the electrical activity of myocardium 16

 Decrease velocity of electrical conduction, prolong refractory period in AV conduction system  Increase vagal tone 17

 Objective 5: relate how the effects of digitalis are beneficial to the client with CHF  Recall the signs/symptoms of CHF  How do you think cardiac glycosides improve this condition? 18

 Objective 6: describe the usefulness of digitalis in the treatment of atrial fibrillation 19

 What is atrial fibrillation?  What activity of the cardiac glycosides improve this condition? 20

 Chronotropic/dromotropic effects ◦ Suppress impulse conduction through the AV node ◦ This prevents excessive atrial activity from reaching ventricles 21

 Objective 7: list the generic and brand names of the digitalis preparations  Digitalis preparations similar in pharmacological properties, toxic effects 22

 Digoxin (Lanoxin, Lanoxicaps): oral or IV  Onset minutes oral  Peaks 2-6 hrs  Duration 2-4 days  Eliminated by kidney ◦ Used most often as rapid onset, short duration 23

 Must take apical pulse 1 minute before administration  Hold if under 60, contact MD  Blood levels needed 24

 Objective 8: define digitalization 25

 Digitalization is the administration of digitalis that is more than the maintenance dose  This raises the blood level quickly to therapeutic range ◦ May also be called a loading dose 26

 Example ◦ Oral dose of digoxin mg ◦ mg then given every 6-8 hours until desired blood level reached ◦ Then maintenance dose: mg daily 27

 Objective 9: list symptoms of digitalis toxicity 28

 Digitalis toxicity: ◦ GI distress: N/V, anorexia, and/or diarrhea (flu like symptoms) ◦ May have excessive salivation and abdominal pain ◦ Neurological: restless, irritable, lethargy, drowsiness, and/or confusion 29

 May have vision changes, changes in color ◦ May have halos, amblyopia and diplopia ◦ Cardiac effects: development of arrhythmias (bradycardia, primary AV block) 30

 Objective 10: identify factors which predispose digitalis toxicity 31

 Toxicity predisposition: hypokalemia as cardiac muscles more sensitive to the glycosides  Renal impairment as 60-90% excreted by kidney  IV administration: rapid accumulation can occur 32

 Treatment ◦ Hold the drug ◦ Use digoxin immune fab (Digibind)  Antigen-binding fragments combine with digoxin to neutralize its action 33

 Objective 11: describe the nursing responsibilities associated with administering cardiac glycosides preparations 34

 Take apical pulse 1 full minute  Hold if under 60, over 100 in adults  Report any evidence of irregular rhythm  Observe for toxicity S/S  Monitor K+ if on diuretics  Encourage K+ rich foods 35

 Teach client to take pulse  Teach S/S of toxicity  If hypothyroid, sensitive to digitalis  Draw blood levels periodically 36

 Atherosclerosis narrows heart’s vessels  Blood flow impeded  Demand exceeds supply = anginal pain 37

 Objective 12: describe the actions of the antianginal drugs 38

 Drugs are used to dilate coronary arteries  This brings in oxygen and nutrients  Supply = demand so no pain 39

 Objective 13: identify the drugs used to treat angina pectoris 40

 Nitroglycerin  Calcium channel blockers  Beta blockers  ACE inhibitors 41

 Nitroglycerin drugs  Works by relaxing arterial and venous smooth muscle  Dilate coronary arteries 42

 Liquid nitroglycerin unstable, highly volatile  Oral tablets stable, non-explosive  Can be given sublingual for rapid, predictable action  Can be transmucosal, aerosol translingual spray, IV, transdermal 43

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 Ointment: placed on paper with inches marked off  Amount prescribed placed on the paper, taped into place  4-8 hours of action  (Nitro-bid, Nitrol) 45

 Nitroglycerin patches: worn hours  “Patch-off” period of 6-12 hours  Prevents tolerance  (Transderm-Nitro, Nitro-Dur) 46

 IV nitroglycerin in early treatment, then another form 47

 Long acting forms for prophylaxis ◦ Erythrityl tetranitrate (Cardilate) ◦ Pentaerythritol tetranitrate (PETN) 48

 Objective 14: list the side effects of nitroglycerin 49

 Tolerance  Headache  Postural hypotension  Dizziness  Weakness  Syncope ◦ Don’t use alcohol with nitros 50

 Nitrates can increase intraocular and/or intracranial pressure 51

 Objective 15: identify the nursing responsibilities associated with administering the nitroglycerin preparations 52

 Teach: when angina occurs, take 3 tabs in 15 min; if no pain relief, call 911  Keep nitro in original container, cap tightly closed  Store in cool, dry place  Rotate sites of topical applications  Monitor BP during therapy 53

 Shelf-life is 6 months. If burning/stinging sensation under tongue, drug still potent  Replace 3 months after opening bottle 54

 Objective 16: identify the beta-adrenergic blocker used to treat angina 55

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 Examples: propranolol, Atenolol  Decrease heart rate, contractility ◦ Results in reduction of myocardial oxygen consumption ◦ Better if used with nitrates  Can not use in COPD, CHF, heart block, bradycardia, DM 57

 When used with nitrates, hypotensive episodes more likely to occur  Drugs used ◦ Atenolol (Tenormin)--prototype ◦ Metoprolol (Lopressor) ◦ Nadolol (Corgard) ◦ Propranolol (Inderal) 58

 Objective 17: identify the calcium channel blockers used to treat angina 59

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 Nifedipine (Adalat, Procardia)  Diltiazem HCl (Cardizem, Dilacor SR)-- prototype  Verapamil (Calan, Isoptin)  Bepridil (Vascor)  Nicardipine HCl (Cardene) 61

 These drugs create coronary vasodilation, increased coronary blood flow, lowered blood pressure, increased cardiac output, and relax coronary artery spasms 62

 Objective 18: identify the ACE inhibitors used to treat angina 63

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 The angiotensin-converting enzyme inhibitors decrease myocardial oxygen demands 65

 Captopril (Capoten)  Lisinopril (Prinivil)--prototype  Ramipril (Altace) 66

 Objective 19: nursing care 67

 Frequency, nature, precipitants of angina attack  Lifestyle changes made  Effectiveness of coronary vasodilators in relief of pain  Monitor VS, esp. BP 68

 Ineffective tissue perfusion, cardiac function RT angina  Risk for injury RT side effects of coronary vasodilators  Deficient knowledge RT health alteration and medication regimen 69

 What teaching is done for clients taking nitroglycerin?  What teaching is done for clients taking calcium channel blockers, ACE inhibitors, beta blockers?  What will the nurse monitor when clients are on these medications? 70