dig toxicity

Question 1

digoxin has a positive inotropic properties mechsnism of action

Answer 1

decreases conduction through the atrioventricular node
slows the ventricular rate in atrial fibrillation and flutter
increases the force of cardiac muscle contraction due to….. inhibition of the Na+/K+ ATPase pump.
Also stimulates vagus nerve
digoxin has a narrow therapeutic index

Question 2

digoxin has a very narrow What?

Answer 2

Therapeutic range

Question 3

Digoxin is not monitored routinely except when suspecting toxicity , how often is digoxin tested?

Answer 3

Concentration tested 8 -12 hours the last dose

Question 4

Features is digoxin toxicity?

Answer 4

lethargy,
nausea & vomiting,
anorexia, confusion,
yellow-green vision
arrhythmias (e.g. AV block, bradycardia)
gynaecomastia

Question 5

Precipitating factors of digoxin

Answer 5

Hypokalemia - as digoxin binds to the potassium site of the sodium potassium ATpase pump

renal failure

myocardial ischaemia

hypomagnesaemia,
hypercalcaemia,
hypernatraemia, acidosis

hypoalbuminaemia
hypothermia
hypothyroidism

drugs: amiodarone, quinidine, verapamil, diltiazem, spironolactone (competes for secretion in distal convoluted tubule therefore reduce excretion), ciclosporin. Also drugs which cause hypokalaemia e.g. thiazides and loop diuretics

Question 6

Mx of digoxin

Answer 6

Digibind
correct arrhythmias
monitor potassium