Mode of action of digoxin || Pharmacology || Anurag Gupta & Anasmoinuddin

Mode of action of digoxin || Pharmacology ||Anurag Gupta & Anasmoinuddin

1. Mode of action of digoxin Anurag Gupta

2. INTRODUCTION of C.H.F. It is a pathophysiological chronic progressive disorder where the heart is not able to pump sufficient amount of blood required by the metabolic demand of the body. Impaired ability to fill or eject blood Abnormal increase in blood volume Arteriosclerotic heart disease Myocardial heart disease Long standing hypertension Valvular heart disease

3. MAIN CAUSE Systole dysfunction Diastole dysfunction Role of physiological compensatory mechanism

4. DIGOXIN It is cardiac glycoside used to treat various heart conditions such as Arterial fibrillation , arterial flutter and heart failure. R.O.A- Oral & I.V Therapeutic range- 0.8 ng/ml Toxicity range > 2.4 ng/ml Metabolism - 16% Liver

5. Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ ATPase 3Na + 3Na + Low[Na + ] High[Na + ] 2K + Na + /K + pump Na + /Ca 2+ exchanger Ryanodine receptor Ca 2+ Muscle contraction L type Ca +2 channel

6. When Na + level fall Sarcoplasmic reticulum Inactive Causes low level of Ca 2+ Get exhausted and fail to work C.H.F. Leads to weak myocardial systole This causes accumulation of blood in ventricles Leads to weak myocardial distention Heart tries to expel this accumulated blood volume Pathophysiology

7. Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ ATPase 3Na + 3Na + Low[Na + ] High[Na + ] 2K + Na + /K + pump Na + /Ca 2+ exchanger Ryanodine receptor Ca 2+ Muscle contraction Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ L type Ca 2+ channel Digoxin

8. M.O.A. Of Digoxin Digoxin Blocks Na+/K+ ATPase Pump Now more of Ca2+ pumped into S.R. through Ryanodine receptor Increase Na+ level intracellularly Now it lowers the activity of Na+/ca2+ exchanger to remove Ca2+ Action potential travels Ca2+ influx -open L-type channel

9. Ca2+ bind to Ryanodine receptor Lots of Ca2+ inside S.R. Relieves Congestion Now S.R. activates and causes forceful contraction Leads to complete emptying of Heart (ventricles) Restore myocardial function

10. Adverse effect of digoxin CARDIAC EFFECT = Arrythmia(Tachycardia) , Hypokalemia GIT EFFECT = Anorexia , Nausea , Vomiting , Diarrhea CNS EFFECT = Headache , Fatigue , Blurred vision

11. DATA ANALYSIS

12. Cyanide