Week 5 - Cardiac continued Flashcards by Nicole Hayashi

Mechanism of Cardiac Glycosides `

Inhibit sodium/potassium pump to increase intracellular Calcium during depolarization

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What effect do cardiac glycosides have on the conduction of SA to AV?

Slows conduction - Always check HR before giving!

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Cardiac Glycoside have: 
\_\_\_\_\_\_\_ inotropic effect 
\_\_\_\_\_\_\_ chronotropic effect 
\_\_\_\_\_\_\_ dromotopic effect 
\_\_\_\_\_\_\_ stroke volume 
\_\_\_\_\_\_\_ cardiac output 
\_\_\_\_\_\_\_ peripheral and lung fluid retention 
\_\_\_\_\_\_\_ fluid excretion

Positive inotropic effect
Negative chronotropic effect
Negative dromotopic effect
Increases stroke volume
Increases cardiac output
Decreases peripheral and lung fluid retention
Increases fluid excretion

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Indications for cardiac glycosides

CHF, A Fib/flutter, paroxysmal atrial tachycardia

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Cardiac glycoside prototype

Digoxin (Lanoxin)

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Digoxin dosage (PO, IV, Elderly, children )

PO: 0.5 - 1mg initially in 2 divided doses (digitalization) , then 0.125 - 0.5 mg/day for maintenance

IV: same as PO but given over 5 min

Elderly: 0.125 mg/day
Children: Doses are ordered in mcg in elixir form

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Digoxin absorption (Oral, Liquid)

Oral: 60-70%
Liquid: 90%

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Digoxin distribution (protein bound and its implication)

LOW protein bound - means there is a lot of active form circulation and thus higher risk for toxicity

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Digoxin half life

30-40 hours

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Digoxin excretion

70% urine through kidney - thus higher risk for toxicity in renal patients
30% by liver metabolism

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Quinidine, Verapamil, Flecainide ______ serum digoxin levels

Increase serum digoxin levels

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Antacids _____ digoxin levels by

Antacids decrease digoxin levels by decreasing absorption

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Thiazides and loop diuretics ______ risk for toxicity because

Increase risk for toxicity because they can cause hypokalemia, which intensifies effects of digitalis

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Hypomagnesemia, hypercalcemia _____ risk for toxicity

Increase risk for toxicity

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Hypokalemia _____ effects of digitalis

Hypokalemia intensifies effects of digitalis

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Digoxin and Ginseng

Ginseng - falsely elevates digoxin levels

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Digoxin and St. John’s Wort

St. John’s Wort - decreases absorption and thus serum level

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Digoxin and Hawthorn

Hawthorn - increases effect of digoxin

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Digoxin and Aloe

Aloe - increases potassium loss, causing hypokalemia which can lead to digitalis toxicity

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Digoxin and Ma Huang

Ma Huang - increases risk for toxicity

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Digoxin and Licorice

Licorice - potentiates effects of digoxin

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Therapeutic serum level of Digoxin

0.5 - 2.0 ng/mL

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The therapeutic serum level is _______. This plus the low PB indicates ______ risk for ______.

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The therapeutic serum level is narrow. This plus the low PB indicates high risk for toxicity.

Signs and symptoms of digitalis toxicity (8)

Study These Flashcards

*Bradycardia, PVC, cardiac dysrhythmias,visual disturbances (green and yellow halos), blurred vision, confusion/delirium H/A, N/V

Who are at greater risk for digitalis toxicity?

Elderly and renal patients

When giving digoxin, always check (4)

- Serum potassium - Baseline apical pulse rate (do not give if below 60) - BUN and creatinine - Signs and symptoms of toxicity

Carvedilol (Coreg) classification

3rd generation Beta blocker (beta receptor antagonist) - NON-selective

Carvedilol mechanism

-Blocks beta 1, beta 2, alpha 1 It's an ANTIOXIDANT -Protects against free radicals causing damage to nucleic acids, proteins, and lipids (which are linked to CAD, atherosclerosis) -Protects from further inflammatory damage or change

Carvedilol is NOT for... (4)

COPD, CHF, Asthma, DM

When should Carvedilol be given?

Early stages of HF to slow progression to CHF

What is the primary line of therapy for majority of patients with HF?

Diuretics

Three categories of diuretics

Thiazides, Loop, Potassium sparing

Diuretic mechanism

Produce net loss of sodium and water acting directly on the kidney to decrease acute symptoms of HF that result from fluid retention (such as dyspnea, edema)

Thiazide mechanism

Inhibits active transport of Cl-Na in the cortical diluting segment of the ascending limb of the Loop of Henle

Thiazide example

Hydrochlorothiazide (HCTZ)

Loop mechanism

Inhibits active transport of Cl-Na-K in the thick portion of the ascending limb of the Loop of Henle

Loop example

Furosemide (Lasix)

Potassium sparing mechanism

- Inhibits REABSORPTION of Na in the distal convoluted and collecting tubules - BLOCKS aldosterone production

What kind of effect do potassium sparing diuretics have on the heart?

Cardioprotective effect - blocks aldosterone in the heart and blood vessels to promote cardiac remodeling (repair inflammation)

What can use of potassium sparing diuretics lead to?

Hyperkalemia

Potassium sparing example

Spironolactone (Aldactone)

What is carbonic anhydrase?

Enzymes found in the proximal convoluted tubule in the kidney that helps maintain balance of hydrogen ion and bicarbonate in our bodies

Carbonic Anhydrase Inhibitors - mechanism

Inhibits action of carbonic anhydrase - causes Na, K, HCO excretion to make pH of kidney tubules alkaline and alkalinizes the urine

Carbonic Anhydrase Inhibitors - uses (2)

- Primarily used to decrease IOP in chronic open angle glaucoma - Can also alkalinize urine in rhabdomyolisis (alkalinizing = protects integrity of tubules)

Carbonic Anhydrase Inhibitor protoype

Acetazolamide (Diamox)

Acetazolamide (Diamox) classification

Carbonic Anhydrase Inhibitor

Acetazolamide (Diamox) side effects (5)

Fluid and electrolyte imbalances, metabolic acidosis, N/V, confusion, orthostatic hypotension

Acetazolamide (Diamox) adverse reactions (3)

Hemolytic anemia, renal calculi, crystalluria

Osmotic Diuretic mechanism

Pulls large amounts of fluid into the urine by osmotic effect

Osmotic Diuretic uses (2)

- Decrease IOP or intracranial pressure | - Prevent kidney failure in Cisplatin chemotherapy

Osmotic Diuretic prototype

Mannitol (Osmitrol)

Mannitol mechanism

As a sugar, pulls large amounts of fluid into the urin by osmotic pull of the sugar

Mannitol side effects (3)

N/V, fluid and electrolyte imbalance, pulmonary edema

Mannitol contraindications (2)

- HF - because if you're increasing intravascular volume, you further congest the HF patient - Renal Failure - they're not making urine so they cannot get rid of the fluid you're pulling out

Mannitol can ______ in vial if exposed to ________. Do not infuse if ______ are present.

Mannitol can crystallize in vial if exposed to low temperature. Do not infuse if crystals are present.

Week 5 - Cardiac continued Flashcards

(55 cards)