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How often is Digoxin given?
Every 24-48 hours
How much per day should Digoxin be given?
What are the ADR for Digoxin?
- AV block
- Other atrial and ventricular arrhythmias
When using Digoxin, what will increase Cardiac ADRs?
Low serum K+
What is the antidote for Digoxin?
Digoxin Immune FAB (Digibind)
What other drug should you be careful about when giving Digoxin and why?
- Kidneys will excrete K and Na which can cause a Hypokalemia which will affect Digoxin and may cause adverse cardiac effects
What is the MOA for Digoxin?
- Inhibits Na-K ATPase Pump
- ↑ Na+ intracellularly which prevents Na/Ca exchanger from working
- ↑ Ca2+ intracellularly = ↑ myocyte contractions
- Affects AV nodal conduction = ↓ HR
How is Digoxin eliminated?
Primarily renal elimination
What drugs affect AV node?
- Class II - B-blocker
- Class IV - Ca2+ channel blocker
What are the 3 direct drug mechanisms that increase myocardial contractility?
- Inhibits Na-K ATPase Pump (Digoxin)
- Blocks B-Blockers (B-agonists)
- Inhibits PDE3 which converts cAMP --> AMP
How do B-receptor blockades have a therapeutic effect in CHF?
Peripheral vasoconstriction and by impairing sodium excretion by the kidneys
What are the B-blockers used to treat CHF?
- Metoprolol - B-1 Blocker
- Bisoprolol - B-1 Blocker
- Carvedilol - α-1 receptor blockade
What are the drugs/ drug targets in the renin-angiotensin-aldosterone system in the tx of CHF?
- B1 receptor antagonists
- ACE inhibitors
- AT1 receptor antagonists
Using Frank-Starling diagrams, what are the drug tx options for CHF?
- Inotropic drugs
What are the 2 goals for Heart Failure and how do you do it?
- ↓ Pulmonary Congestion - ↓ PRELOAD
- ↑ CO - ↓ SVR (AFTERLOAD), ↑ Contractility, ↑ HR
What are the 3 ways to ↑ CO?
- ↓ SVR (AFTERLOAD)
- ↑ Contractility
- ↑ HR
How do you ↓ Pulmonary Congestion?
What are the effects of Beta- Agonists?
- ↑ Contractility (+ inotropy)
- ↑ Relaxation Rate (+ lusitropy)
- ↑ HR (+ chronotropy)
- ↑ Conduction Velocity (+ dromotropy)
- Smooth muscle relaxation (vasodilation)
- Hepatic glycogenolysis
- Pancreatic release of glucagon
- Renin release by kidneys
Where is the PDE isoenxyme found?
- Myocardium on LV
- Peripheral arterioles
What are PDE-3 inhibitors?
What are 2 PDE-3 drugs that have IV constant infusion?
Which drug will block renin release?
Which drug will inhibit Angiotensin I production?
Direct renin inhibitor
Which drug will inhibit angiotensin II production?
Which drug will inhibit AT-1 receptor stimulation?
Which drug will inhibit action of aldosterone on kidney?
Aldosterone antagonist (spironolactone)
What drugs will decrease preload?
- Diuretics (Loop)
- Nitrates (venodilators)