Drugs used for the management of heart failure Flashcards
Clinical trials proved which medication is best for improving the CO?
Vasodilators, and not positive inotropes
What is the clinical importance of digoxin?
Digoxin/cardiac glycoside will reduce the times the patient is hospitalized but it will not prolong the life expectancy when compared to vasodilators or (ACEi, ARB, and BB to a lesser extent)
What are the indications of positive ionotropic drugs?
- They increase the workload on the heart, used in:
1) Heart Failure
2) In refractory when other drugs are not working
What are the non-pharmacological therapy of HF?
1) Sodium restriction
2) Aerobic exercise (mild, and under supervision)
3) Weight loss
4) Treat the hypertension and the comorbidities
What are the pharmacological treatments of HF?
1) ACEIs
2) ARBs
3) Aldosterone antagonists
4) B-blockers
5) Vasodilators (like hydralazine)
6) Diuretics (very imp in acute pulmonary edema and we give it in huge doses of furosemide (most potent) to decongest the lung that is of course if the BP can handle it)
7) Digoxin
8) Device therapy
9) Cardiac resynchronization therapy
10) Implantable defibrilators
11) Left ventricular assist devices
What is the body’s compensatory mechanism for HF?
- In case of decreased CO
1) Increase in the sympathetic outflow due to decreased carotid sinus firing rate, which will ultimately increase the rate, force, preload and afterload of the heart, increasing the CO
2) Activation of the RAAS, increasing the secretion of renin and thus angiotensin-2, which will ultimately increase the afterload and preload increasing the CO
What is meant by the vicious circle?
- When the CO DECREASES THIS WILL INDUCE VASOCONSTRICTION WHICH WILL INCREASE THE AFTERLOAD, however, the heart cannot pump against that increased afterload decreasing the CO further
- To break this cycle vasodilators are used
What is the effect of beta-adrenergic blockers in HF?
At specific dosages, BB improves HF by blocking the increased outflow of the sympathetic system, but only specific BB
Which BB is used in HF?
- MBC3
1) B1 selective blocker
- Bisoprolol
- Metoprolol
2) Non-selective third generation BB
- Carvedilol
Why is it important to use vasodilators in HF?
- They decrease both the preload and afterload
- Oral vasodilators usually are used in patients with chronic HF and parenteral agents are reserved for those who have severe HF or are unable to take oral medications
What are the positive ionotropic agents used in HF?
1) Digitalis glycoside
- Mainly digoxin (Oral or intravenous)
2) Phosphodiesterase inhibitors
- Inamrinone
- Milrinone IV
3) Dobutamine and Dopamine
4) Human natriuretic peptide
- Nesiritide
5) Endothelin receptor antagonists
What is the pharmacology of digoxin on the CVS?
1) Positive ionotropic action (as it inhibits the Na+/K+ ATPase pump)
2) Increases the parasympathetic activity
3) It has a negative chronotropic effect
What is the mechanism of action of digoxin?
1) It blocks the sodium-potassium pump (which pumps 3 Na+ out and two K+ in)
2) Intracellular Na+ would be high, inhibiting the Na+/Ca2+ pump and increasing the intracellular levels of calcium
- Which will all lead to more contractility due to the binding and blocking of digoxin to the Na+-K-ATPase pump
What are the effects of digoxin on the heart?
1) Improves the pumping ability of the heart in HF
2) Increases the myocardial contractility allowing the ventricles to empty more completely with each beat
3) Improves the CO by decreasing the (Heart size, rate, end-systolic/diastolic pressure, etc)
What is the pharmacokinetic of digoxin?
60% of it is excreted renaly, and largely unchanged
- Give loading dose as its half-life is 36-40 hours with normal renal function
- It also crosses the placenta, and serum levels in neonates are similar to those in the mother
