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Pharm Cardiac Drugs

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insanitycrossing's version from 2016-09-03 17:43

Section 1

Question Answer
What is digitalis the preferred treatment for?atrial fribrillation/flutter
What is digitalis combined with? (digioxin negates some side effects of this)quinidine
Does digitalis need a loading dose?YES
When are the slow, rapid, and intensive methods used?Slow: mild cardiac failure, Rapid: doesn't say Intensive: EMERGENCY
Are cats or dogs more sensitive to digioxin?CATS
Do you use the animals fat or lean body weight to calculate the dose for digioxin?Lean, digitalis is poorly distributed in fat
Do you increase or decrease the dose in animals with renal and liver problems?DECREASE
When do you give digitalis IV?Can't keep oral medication down, acute cardiac decompensation/respiratory distress
When do you give digitalis IM?NEVER
Signs of Digitalis toxicityvomiting, diarrhea, chronic weight loss, arrhythmias
Cardiac arryhthmias in digitalis toxicitycan be incomplete or complete with dropped beats, also causes ventricular bigeminal rhythm
Ventricular bigeminal rhythmextra QRS after each normal systole
Does hyperkalemia make digitlalis toxicity worse or better?Better, hypokalemia would make it worse!
Why does increased potassium levels help with digitalis toxicity?competes with digitalis for binding on NaKATPase
Does hypercalcemia make digitalis toxicity better or worse?WORSE: increased calcium is available for heart contractions so this makes the effects of digitalis toxicity worse
What should be given in severe digitalis toxicity?Cholestyramine to bind to glycoside in GIT which prevents it from being reabsorbed and forces it be excreted
FurosemideDiuretic used in CHF. Luminal membrane of thick ascending limb of Henle to inhibit Na/K/Cl co transport
Thiazideinhibvits Na/Cl symporter in distal convoluted tubule, increases excretion of K and resorption of Ca be careful!
Spinronolactonealdosterone antagonists (K+ sparing diuretic)
Triamterene and amiloridedirectly inhibit resorption of Na
memorize

Section 2

Question Answer
What are inamrinone and milrinoneinodilators: peripheral vasodilation and inotropic on heart
How do inodilators work?inhibit phosphodiesterase III which allows cAMP to accumulate in heart and smooth muscle vasculatur--> increased cardiac contraction and peripheral vasodilation
InamrinoneInotropic without increaseing myocardial O2 consumption, decreases preload and afterload
Pimobendanphosphodiesterase III inhibitor: Inotropic and vasodilation. increases binding efficiency of carediac myfibril to Ca. LACKS ARRHYTHMOGENICITY
Beta adrenergic agonistdobutamine
Dobutaminepositive inotropic, decreases preload, weak chronotropic action (tachycardia)
Drawbacks to Dobutaminearrhythmias with ischemic heart condition, tachyphylaxis, short half life so need continuous IV
Clinical indications of dobutamine in dogsacute treatment of dilated cardiomyopathy with CHF. Alternative to dopamine for cardiogenic shock
Use of dopamine in horseshypotension during anesthesia
Aminophyllineinhibits phosphodiesterase enzyme in cardiac tissue but is primarily a bronchodilator.also causeses weak inotropic and mild diuresis
Use of aminophyllineacute pulmonary edema
memorize

Section 3

Question Answer
Sodium nitroprussidearteriol and venous dilator, used in hypertensive emergencies, IV, release NO
why would you give dogs dobutamine along side sodium nitropursside?compensate for hypotension
Nitroglycerinvascular smooth muscle, rapid onset (emergency treat angina), low bioavailability due to first pass effect
Hydralazine and minoxidildilate arterioles, used in CHF secondary to mitral/aortic valve insufficiency and hypertension
Hydralazine in dogsrapid oral absorption, metabolized by liver, some excreted by kidneys, increase concentration in uremic patients
Side effects of hydralazine in dogstachycardia-> increased O2 demand and cardiac decompensation in dogs with CHF
Prazosinalpha1 adrenergic agonist: peripheral vasodilation with minimal reflex tachycardia
Prazosin in dogsCHF dogs that are refractory to digoxin
Digoxin and prazosin togetherpositive inotropic action of heart and peripheral vasodilation for dogs with CHF
Isoxsuprinebeta2 adrenoreceptor agonist
Ca ch blockersdecreases cardiac contractile force, slows impulse conduction, vasodilation to decrease O2 demand of failing heart
DiltiazepemCa ch blocker, used for hypertrophic cardiomyopathy in dogs and cats
AmlodipineCa ch blocker, hypertension in cats
PDE5 inhibitorsinhibit degradation of cGMP--> relaxes pulmonary blood vessels so used for pulmonary hypertension in dogs
ACE inhibitorsused for heart failure and hypertension
memorize

Section 4

Question Answer
Angiotensin IIdirect vasoconstriction, increase aldosterone production, stimulates sympathetic system
ACE Inhibitorsused in heart failure and hypertension
CaptoprilACE inhibitor, oral bioavailability reduced with food
Enalaprilprodrug-> enalaprilat, transformed in liver, bioavailability not affected by food
Benazepril hydrochlorideprodrug -> benazeprilat transfromed in liver, bioavailability not affected by food
Lisinoprilgreater affinity for ACE than enalapril
Excretion of ACE inhibitorskidney, moniter renal function, reduce doses in renal conditions
NAIDS and ACE inhibitorsdecreases hypotensive effects because it blocks bradykinin induced vasodilation
ACE inhibitors other effectsmild natriuresis, K sparing effect due to decrease Na/K exchange mechanism in renal collecting tubule (decreased secretion of aldosterone)
Captopril and Hydrocholorthiazideenhances antihypertensive effect and decreases K loss
Enalapril and hydrochlorothiazideenhances antihypertensive effect and decreases K loss
ACE inhibitor and thiazide diuretic clinical usehypertension in small animals, stroke prevention in people
Angiotensin receptor blockerslosartan and irbesartan, blocks AT1 but doesn't affect bradykinin activity
Thearpeutic indications of losartan and irbesartanhypertension and heart failure
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Section 5

Question Answer
Furosemideloop acting diuretic, when given by IV increases venous capacitance and thus decreases pulmonary congestion
Morphine sulphateopiod agonist, hypotensive effect by decreasing the reponsiveness of medullary respiratory center to increased PCO2--relieves dyspnea and anxiety associated with left ventricular failure
Digoxingiven to dogs suffering from pulmonary edema with left ventricular failure
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Section 6

Question Answer
Class I antiarrhythimic agentsmembrane stabilizers/local anesthetics
Drugs of Class IQuinidine, phenytoin, lidocaine, procainamide
Class II antiarrhythimic agentsbeta blockers
Drugs of Class IIpropranolol, atenolol, esmolol, metoprolol, carvedelilol
Class III antiarrhythmic agentsprolong action potential duration
Drugs of Class IIIbretylium, amiodaron, sotalol
Class IV antiarrhythimic agentscalcium ch blockers
Drugs of Class IVverpamil, diltiazem
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