Drugs used to Congestive Heart Failure

1. Drugs used in the treatment of Heart failure
CARDIAC GLYCOSIDES
Dr. Abirami

2. Congestive Heart Failure
• Definition
• Heart failure is the condition in which the
heart is unable to pump sufficient amount of
blood to meet the metabolic demands of the
body and also unable to receive it.

3. Cardiac Output Stroke Volume
Cardiac output : the amount of blood pumped
by the heart, in mL/min
Stroke volume: the amount of blood pumped out of the
heart with each heartbeat
cardiac output
(mL/min)
heart rate
(heats/min)
stroke volume
(mL/heat)
Normal stroke volume 50-100ml

6. Actions of the Heart
• 1. Chronotropy- Heart rate or heart beat
• Tachycardia- Increases in heart rate
• Bradycardia- Decreases in heart rate
• 2. Inotropy- Force of contraction
• Positive inotropic action- Increases in force of
contraction
• Negative inotropic action- Decreases in force of
contraction
• Dromotropy- Conduction of impulse
• Positive dromotropic action- Increases in the velocity
of conduction
• Negative dromotropic action- Decreases in the velocity
of conduction
• 4. Bathmotropy- Excitability of cardiac muscle
• 5.Lusitropy- Rate of myocardial relaxation

7. Heart Failure
• The therapeutic goal In the treatment of HF is to increase Cardiac
output (CO)
• Classification
• 1. Drugs with positive inotropic effects
• A. Cardiac Glycosides: Digoxin, Digitoxin, Ouabain
• B. Bipyridines or Phosphodiesterase inhibitors: Inamrinone,
Milrinone, Enoximone
• C. Beta adrenergic agonists: Dopamine, Doputamine, Dopexamine
• 2. Drugs without positive inotropic effects
• A. Diuretics: Furosemide, Hydrochlorothiazide,
Spiranolactone
• B. ACEIs: Enalapril, Lisinopril, Ramipril
• C. AT1 Antagonist: Losartan, Telimisartan
• D. Beta 1 adrenergic antagonists: Bisoprolol, Carvedilol, Metoprolol
• E. Vasodilators: Hydralazine, Sodium nitroprusside

8. Cardiac glycosides
• Source:
• Leaves of Digitalis lanata, Digitalis purpurea
• Digitalis lanata (White fox clove) - Digoxin, Digitoxin
• Digitalis purpurea (Purple Fox clove)- Digitoxin, Gitoxin
• Seeds of Strophanthus gratus- Stophanthin-G and Ouabain
• Seeds of Strophanthus kombe- Strophanthin- K

17. Cardiac glycosides
• Therapeutic uses
• Digoxin is the most preferred drug amongst
the three glycosides.
• Digitoxin is preferred in the cases having renal
impairment.
• Ouabain is reserved for acute heart failure.
• Used in the treatment of Heart failure.
• Paroxysmal supraventricular tachycardia
• Atrial flutter and atrial fibrillation

18. Cardiac glycosides
• Adverse effects and management of toxicity
• Digitalis has cumulative effect and smaller therapeutic window, it
is always safer to prescribe a dose that provides digitalis plasma
concentrations of 0.8-2.0ng/ml.
• 2.5ng/ml is a toxic level.
• Cardiac side effects: Bradycardia, partial or complete heart block,
coupled beats (bigeminy), ventricular fibrillation and fatal cardiac
arrythmias.
• If cardiac arrythmias develop Ca2+, Mg2+ and K+ Status should be
corrected
• For Bigeminy, oral K+ Supplementation and withdrawal of digoxin
may be sufficient.
• If arrythmias are more serious, parenteral K+ and lidocaine may be
administered.

19. Cardiac glycosides
If the automaticity also get depressed at toxic dose,
the patient can be saved by administering digitalis
antibodies e.g: Digibind fab fragments (Digitalis
immune fab)
A 40mg of vial of these antibodies neutralises
0.6mg of digoxin stored in the body.
Extra cardiac side effects: Anorexia, vomitting,
disrrhoea, headache, neuralgia, blurred vision,
loss of color perception, gynacomastia

20. THANK YOU