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16 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Cardiac Glycosides-mechanism of action
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Inhibit Na/K ATPasa--increased Ca2+ in SR-increased Ca2+ release & binding to troponin-tropomyosin moves allowing actin/myosin interaction--increased contractile force & CO
Central Vagal stimulation via PANS--facilitation of muscarinic activity and sensitation to baroreceptors Decreased sympathetic activity High doses: Sympatomimetic (Beta 1 like)+ chronotropy, dromotropy and inotropy |
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Do Cardiac Glycosides improve survival
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No. (ACE/ARB's usually 1st choice to treat HF)
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Drugs that can cause Drug Induced SLE
Antibodies? |
hydralazine,isoniazid, procainamide, penicillamine, phenytoin chlorpromazine, sulfasalazine, methyldopa, and quinidine
(usually after taking the drug at least ~3-6 months) ANA antibody/ anti-histone antibody |
it's not HIPPP to have lupus
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Digoxin
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Most widely used cardiac glycoside (digitalis drug)
Inhibits Na/K ATPase-Ca2+ increased-greater cardiac contractibility (+inotropy) Vagal stimulation-decreased SA nodal rate Sympatomimetic (Beta 1 like)+ chronotropy, dromotropy and inotropy T1/2 20-40 h, renal cl, 25% protein bound, Vd 6 L/kg |
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Digitoxin
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like digoxin but longer T 1/2, hepatic cl, more protein bound
T 1/2 120-160 (vs. 20-40) CL Hepatic (vs. renal) Vd 0.6 L/kg (v.s 6) Protein Binding 90% (vs. 25%) |
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Digitalis Toxicity
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Narrow therapeutic window.
Hypokalemia enhances dig activity ("digitalis pump is inhibited by K+) and hyperkalemia decreases effects Signs: Anorexia, nausea, EKG (decreased QT interval, T wave inversion, PVB's, bigeminy) CNS-disorientation, visual "halos", hallusinations |
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EKG changes in Digitalis Toxicity
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EKG (decreased QT interval, T wave inversion, PVB's, bigeminy)
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Signs of severe Cardiac (Digitalis) Toxicity
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SVT's, AV nodal tachycardia or AV block
VT or VF |
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Management of Digitalis Toxicity
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Adjust electrolytes (made worse with low K+ and Mg and high Ca2+)
Use antiarrhytmics (lidocaine, phenytoin-class 1B) digitalis Fab antibodies (Digibind) Cardiovert only if VF |
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Drug interactions that may cause digitalis toxicity
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low K+, Mg and high Ca2+ (diuretics), quinidine, amiodarone, verapamil, NSAIDs, symptamomimetics and some antibiotics (erythromycin)
* no dig for WPW pt's |
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Inamrinone (Amrinone)
Milrone |
The cyclic AMP–phosphodiesterase (PDE) inhibitors
Inhibit PDE--increased cAMP (via decreased degradation)-- positive inotropy and vasodilation short term support of advanced cardiac failure Amrinone causes thrombocytopenia (10%) and milrinone may decrease survival in heart failure |
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First choice treatment in heart failure
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ACE inhibitors
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Dopamine
low dose 2< micrograms/kg per minute Intermediate 2-5 High 5-15 |
Endogenous Catecholamine
Low dose: vasodilation-via cAMP and D2 causing decreased NE and alpha adrenergic tone (D2 receptors prominent in renal & splancnic vascular beds. (increased GFR) Also direct effects on renal tubular epithelial cells that promote diuresis Intermediate: stimulates beta receptors on the heart and vascular sympathetic neurons (cardiac contractibility) High: no good for CHF. Too much vasoconstriction--increased afterload |
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Dobutamine
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B agonist
Racemic mix. Both stimulate B1 & B2. - form also alpha 1 increase in stroke volume (positive inotrop) No effect on D2--so no independent GFR increase (increase proportional to increase in CO) SE: tachycardia and arrhythmias, tolerance |
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Amlodipine
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Vascular selective CCA
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Carvedilol
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Non-selective beta blocker-decreased refractory pump failure & sudden death
(bisprolol-Beta 1 selective--also survival benefit) and spironolactone (diuretic) Combine tx w/ ACEI |
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