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53 Cards in this Set
- Front
- Back
name the classes of drugs that are cardiac inotropic drugs?
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sympathomimetic drugs, digitalis glycosides, phophodiesterase III inhibitors, phosphodiesterase III inhibitors/calcium sensitizers
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name some sympathomemetic drugs that are cardiac inotropes?
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epinephrine, isoproterenol, dobutamine
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name some digitalis glycosides that are cardiac inotropes?
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digoxin, digitoxin, ouabain
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name some phosphodiesterase III inhibitors?
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milrinone, amrinone
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name some phosphodiesterase III inhibitors/calcium sensitizers?
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pimobendan
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what acronym do we follow to manage cardiac arrest?
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ABCDEF
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how do we manage cardiac arrest?
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airway, breathing, CPR (chest compression), drugs, ECG (monitor rate and rhythm), fluids
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what is the action/organ that alpha1 receptors affect?
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contract pilomotor smooth muscles, gluconeogenesis in liver, secretion of sweat glands, increase tone of urethra smooth muscles, and constrict peripheral & splanchnic vessels (with alpha2)
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what is the action/organ that beta2 receptors affect?
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dilate skeletal muscle vessels, relax bronchial smooth muscles, stabilize respiratory mast cells
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what is the action/organ that beta1 receptors affect?
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increase heart rate and contraction
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what is the action/organ that alpha2 receptors affect?
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constrict peripheral and splanchnic vessels (with alpha1)
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what receptors does norepinephrine affect?
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a1 (+++), a2 (+++), B1 (++)
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what receptors does epinephrine affect?
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a1 (+++), A2(++), B1 (+++), B2 (+++)
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what receptors does dobutamine affect?
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a1 (+), B1 (+++), B2 (+)
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what receptors does dopamine affect?
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a1 (+), B1 (+++), DA (+++)
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what receptors does isoproterenol affect?
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B1 (+++), B2 (+++)
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freebie
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freebie
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freebie
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freebie
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what reaction does epinephrine cause and at what receptors?
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a1 & a2 = vasoconstriction, B2 = bronchodilation & vasodilation, B1 = increased heart rate & increased contractility & increased conduction
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what are the primary receptors affected by epinephrine?
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B1, B2 & a1
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what are the primary receptors affected by norepinephrine?
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B1, a1
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what are the primary receptors affected by isoproterenol?
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potent B1 & B2
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what type of agent is epinephrine?
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sympathomimetic agent
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what type of agent is norepinephrine?
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sympathomimetic agent
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what type of agent is isoproterenol?
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sympathomimetic agent
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what drug, besides epinephrin, is used to treat cardia arrest?
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vasopression (argine vasopressin, AVP)
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what does vasoppresin do at what receptors?
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acts at V1, V2, V3 receptors, pressor effect mediated by V1 receptors on vascular smooth muscle
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what drugs would we use to treat acute cardiogenic pulmonary edema?
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positive inotropic agent (dobutamine) diuretics (furosemide), vasodilators (nitroprusside: maintain mean arterial pressure > 70 mmHg), oxygen therapy (supplemental O2)
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what does dobutamin hydrochloride do at what receptors in treating acute cardiogenic pulmonary edema?
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B1 is cardioselective, a1 & B2 have minor effects: positive cardiac inotrope, minimum increase in heart rate
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what determines the dosage of dobutamine hydrochloride for treating acute cardiogenic pulmonary edema?
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half life = 2-3 min, CRI; adjust infusion rate by clinical response
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what adverse reactions may occur when using dobutamine hydrochloride to treat acute cardiogenic pulmonary edema?
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high doses will cause increased heart rate and arrhythmias. Do NOT mix with alkalinizing solutions.
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what are the effects of low dose dopamine?
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stimulates DA1 receptors & increase renal perfusion
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what are the cardiovascular effects of moderate dose dopamine?
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stimulates B1-receptors on heart & positive inotropic and chronotropic effect
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what are the cardiovascular effects of high dose dopamine?
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stimulates a1 vascular receptors & increases vascular resistance & decreases renal perfusion (tachycardai, vasoconstriction, tissue necrosis if administered outside vein)
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what is the non-cardiac uses of dopamine?
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acute renal failure: via action on DA1 & DA2 receptors proposed to increase renal perfusion; no clinical evidence of benefit
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what are the components addressed in management of heart failure?
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treat valvular insufficiency with a positive iotrope which decreased contractility and decreased cardiac output which results in renin-angiotensin -aldosterone imbalance which is treated with diuretic, ACE-inhibitor. The decreased cardiac output causes increased sympathetic tone which leads to tachycardia that is treated with negative chronotrope and vasoconstriction that is treated with a vasodilator
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what cardiac inotropic drugs can be used to treat heart failure?
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digitalis glycosides (digoxin, digitoxin, ouabain), phosphodiesterase III inhibitors/calcium sensitizers (pimobendan), & NOT LONG TERM: phosphodiesterase III inhibitors (mitrinone, amrinone) sympathomimetic drugs (epinephrine, isoproterenol, dobutamine)
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what are the direct effects of digoxin?
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(1) inhibit NA+/K+ ATPase (2) increasese exchange of Na+ for Ca++ (3) increases intracellular Ca++ (4) more intracellular Ca++ available for contraction
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what are the neuroendocrine effects of digoxin?
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increase (restores) baroreceptor reflex sensitivity, decreases sympathetic tone, increased vagal tone
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what are the clinical effects of digoxin?
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slowed sinus rate & decreased AV conduction
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what needs to be monitored with digoxin?
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concentration due to narrow therapeutic index
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what affects the therapeutic concentration of digoxin?
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oral absorption rates (tablet 60% absorption, elixer 85% absorption), clearance impaired with renal disease, collect samples 4 and 12 hours after last dose
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what are the clinical uses of digoxin?
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increase force of contraction, slow heart rate, decrease conduction through AV-node
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what diseases are treated with digoxin?
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heart failure, cardiomyopathy, atrial fibrillation
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what are the adverse affects of digitalis?
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GI (anorexia, nausea, vomiting, diarrhea), cardiovascular (heart block, arrhythmias)
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how does digitalis interact with electrolytes?
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low K+ enhances toxicity, high K+ reduces digoxin effects, high Ca++ may increase effects
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name phosphodiesterase III inhibitors?
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milrinone, amrinone (not available in vet med), pimbendan (also a calcium sensitizer), levosimndan (also a calcium sensitizer)
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what are the effects of pimobendan?
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weak effects in myocardium & peripheral effects of vasodilation
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what is an inodilator?
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a drug that causes positive inotropic effects (calcium sensitizer) and vasodilation (PDE III inhibitor)
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what drug is an inodilator?
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pimobendan
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what is the direct affect of pimobendan?
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increases sensitivity to tropinin C to intracellular Ca++, increases contraction without increasing energy expenditure, may have additional cardiac effect (restore baroreceptor sensitivity, modulates cytokines associated with heart failure)
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compared to ACE inhibitors, what is the efficacy of pimobendan?
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with furosemide (for both drugs), pimobendan supports longer survival, improved clinical signs, and few adverse effects
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what are the adverse affects of pimobendan?
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early treatment of heart disease may cause adverse cardiac effects; worsening mitral valve disease, increase in cardiac lesions
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