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31 Cards in this Set
- Front
- Back
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what is the mech of action of digoxin
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Overall, it makes the heart more efficient by increasing contractility and decreasing HR
Digoxin inhibits the sodium-potassium ATPase pump, by binding to the a-subunit. This leads to an increase in intracellular Na, reducing the Na-Ca exchanger; resulting in an increase in intracellular calcium and thereby an increase in calcium stored in the sarcoplasmic reticulum. With more calcium released from the SR during an action potential, there is an increase in cardiac contractility. Digoxin also has a parasympathomimetic effect, causing an increase in effective refractory period (ERP) and decrease in conduction velocity at the AV node. Digoxin decreases the ERP of atrial and ventricle tissue. |
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How does digoxin affect an EKG
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increase in PR interval
decrease in QT interval T wave inversion ST depression |
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what are the adverse reactions to digoxin
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Heart –
AV block ventricular tachycardia ventricular fibrillation atrial arrhythmias Gastrointestinal – nausea, vomiting, diarrhea, anorexia CNS – disorientation, hallucinations, color vision disturbances, agitation, occasional convulsions Endocrine – gynecomastia |
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what are the Therapeutic Uses of digoxin
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congestive heart failure (with 3rd heart sound)
atrial fibrillation |
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what is the mech of action of Inamrinone and Milrinone
what are they used for |
These are phosphodiesterase (PDE3) inhibitors, inhibiting the breakdown of cAMP and cGMP. This leads to an increase force of contraction of the heart and vasodilation. They are used in treatment of acute CHF
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what is dobutamine used for
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to increase force of contraction in CHF
increase HR to less of an extent than other Beta agonists |
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name the 3 diuretics and give their effect on K+ levels
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Hydrochlorothiazide (hypokalemia)
Furosemide (hypokalemia) Spironolactone (hyperkalemia) |
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which diuretic reduces morbidity and mortality in patients with severe heart failure receiving ACE inhibitors
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Spironolactone
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what is the effect of ACE inhibitors
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reduces sympathetic activity and aldosterone release
results in: decrease in peripheral resistance (dec. afterload) reduction in sodium and water retention (dec. preload) reducing long term remodeling of heart and vessels, decreasing mortality and morbidity |
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How is Losartan diff from other ACE inhibitors
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it is an inhibitor of angiotensin II (AT1) receptors
it doesn't produce a cough |
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name the vasodilators and what they dilate
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Nesiritide (synthetic brain natriuretic peptide)--arteries and veins
Nitroprusside Nitroglycerin--veins Hydralazine--arteries |
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When can beta blockers be used
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stable heart failure
it will make acute heart failure worse |
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name the class 1A antiarythmic drugs and give their potency as Na channel blockers and their effect on the refractory period
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Quinidine, procainamide, disopyramide
Moderate slowing of upstroke velocity Some prolongation of refractoriness |
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name the class 1B antiarythmic drugs and give their potency as Na channel blockers and their effect on the refractory period
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Lidocaine, Mexiletine
Mild slowing of upstroke velocity No prolongation of refractoriness |
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name the class 1C antiarythmic drugs and give their potency as Na channel blockers and their effect on the refractory period
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Flecainide, Propafonone, Moricizine
Marked slowing of upstroke velocity Not much prolongation of refractoriness |
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what does the term use dependent mean
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some antiarrythmic drugs will bind more tightly when the channels are open
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what test is used to monitor warfarin
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Prothrombin time (PT)
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what test is used to monitor heparin
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Activated Partial Thromboplastin time (APTT)
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what are the advantages of enoxaprin (a LMW heparin) over heparin
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Decreased tendency to cause HIT
Less osteoporosis Dose Monitoring not needed |
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What is used to treat HIT (heparin induced thrombo)
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lepirudin (if normal kidney function)
otherwise argatroban |
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What is INR and what range should it be in
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INR is proportional to (PT test)/(PT control) using international reference thromboplastin
INR should be adjusted to 2.5 -3.5 in many cases |
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what is Abciximab
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Anti-platelet drug
A monoclonal chimera (Fc = human, Fab = mouse) antibody to the platelet receptor for fibrinogen Needs to block greater than 90% of receptors to be effective |
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what is Eptifibatide (Integrelin)
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Peptide (73 AA) used to block fibrinogen receptors
Similar otherwise to abciximab |
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What is the effect of niacin
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lowers VLDL and LDL raises HDL
Decreased secretion of VLDL (which leads to less LDL) Increases HDL due to reduced catalysis of HDL Beneficial side effect - lowers circulating fibrinogen and increases t-PA release |
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what are the side effects of niacin
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Most patients experience cutaneous flushing and sensation of warmth -
Itching and rashes GI disturbances - nausea and abdominal discomfort Contraindicated when patient has peptic ulcers Possible liver toxicity |
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what is the mech of action and effects of fibric acids
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Ligand for a nuclear transcription regulator (PPAR-a). This increases the expression of lipoprotein lipase activity
Lowers plasma VLDL levels Results in lowered triglyceride and cholesterol Increases HDL cholesterol moderately Variable effect on LDL |
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what are the toxicities of firbric acids
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GI upset - mild GI disturbances
Increased risk of gallstone formation Potentiation of the effect of warfarin -dosage of warfarin must be lowered Myopathies (rare) |
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what is the mechanism and effects of Ezetimibe
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Selective inhibitor of intestinal absorption of cholesterol and phytosterols. It inhibits reabsorption of bile cholesterol.
Lowers the level of LDL in the blood |
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what are the side effects of statins
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Mild GI upset
Liver toxicities - measure liver enzymes yearly Myopathies and rhabdomyosis - rare but creatine kinase should be monitored. Can cause an increase in free warfarin |
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what are the adverse effects of thiazide diuretics
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muscle weakness and fatigue
Potassium loss Normal potassium 4 mEq/L Muscle cramps 3 – 3.5 mEq/L Cardiac arrhythmias <3 mEq/L Hyperglycemia Hyperlipidemia |
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what is Spironolactone (Aldactone)
or Triamterene (Dyrenium) or Amiloride (Midamor) |
K+ sparing diuretic
Used in combination with thiazide or loop diuretics |
