Digoxin-cardiac glycoside and its pharmacology.

DESCRIPTION : 

 A carddiotonic glycoside obtained mainly from Digitalis lanata ,it consist of 3- sugar & a aglycon digoxigenin .Digoxine has positive inotropic &negative chromotropic activity .It is used to control ventricular rate in atrial fibrilation and in the management of congestive heart failure with atrial fibrilation .This compound belongs to the class of organic compound known as cardinolide glycoside & derivative .These are a compound containing carbohydrates glycosidically bound to the cardinolide meoity .

PHARMACODYNAMICS : 

 Digoxin  ,a cardiac glycoside similar to digitoxin, is used to treat cngestive heart failure & supraventricular arrhythmias due to re-entry mechanism & to control ventricular rate in the treatment of chronic atrial fibrilation .

MECHANISM OF ACTION: 

 Digoxin inhibit the Na-k Atepase membrane pump ,resulting in an increase in intracellular sodium.The sodium calcium exchanger turns tries to extrude the sodium & in so doing ,pumps  in more calcium .Increased intracellular concentration of ca+2 may promote activation of contractile proteins .Digoxin also act on the electrical activity of the heart increasing the slope of phase 4 depolarisation ,shortning the action potential duration & decreasing the maximal diastolic potential .

ABSORPTION :

 From the elixir pediatric formulation has been demonstrated to be 70%to 85%.

PHARMACOKINETIC PROPERTY :

Protein binding - 25 %

Metabolism :Hepatic

 Half life  :  3.5 to 5 days

ADVERSE EFFECT  :

             ventricular tachycardia ,

              Anorexia

              Nausea

              Vomiting

              Abdominal pair

              restlessness

              Hyperapnoea

              Fatigue

DRUG -DRUG INTERACTION : 

           

             Acarbose +Digoxin  =  The serum concentration of digoxin can be decreased .

            Acebutolol + Digoxin = May increase the bradycardiac activity of digoxin

            Adenosine + Digoxin = The risk of severity of adverese effect can be increased when digoxin                                                    is combined with adenosine .

            Amiodarone + Digoxin = Serum concentratin of digoxin can be increased.

           Atazanavir + Digoxin =Serum concentration of digoxin can be increased.

FOOD INTERACTION :

          Avoid avacado

          Avoid bran and high fiber food

           avoid excess salt

           avoid milk ,iron ,antacids

THERAPEUTIC USES :

           congestive heart failure

           cardiac arrhythmias

REFERENCE:-Tripathi K D"Essential of medical pharmacology",7th edition ,page no. 512-19,521,529,536,538,