Digoxin Toxicity Flashcards
how might someone present with digoxin toxicity
fainting semiconscious hypotensive bradycardic junctional rhythm on ECG
what is digoxin used to treat
CHF
afib
atrial flutter
how does digoxin work
increases the force/velocity of myocardial contraction without increasing myocardial oxygen consumption and is an AV nodal blocker
inhibits Na-K ATPase resulting in decreased intracellular K and increased Na/Ca intracellularly
how is digoxin excreted
80-90% is eliminated unchanged by the kidney, remainder is metabolized by the liver
half life of digoxin
1.6 days (increased to 4-6 days in severe renal impairment)
when do you get peak digoxin plasma levels
2-3 hours post dose
peak tissue level and maximum therapeutic response at 6 hours
what is the therapeutic range of digoxin
narrow
0.6-2.5
when do you get symptoms of toxicity for digoxin
above 3.1 mg/ml
in what cases might you develop digoxin toxicity even when digoxin is in therapeutic range
if you also have... hypokalemia hypomagnesemia hypercalcemia chronic disease states like cardiac, pulmonary, hypothyroid
what are the mechanisms of digoxin toxicity
ingestion (acute vs chronic)
co ingestions–> quinidine, verapamil, nifedipine, amiodarone
excretion–> volume contraction, renal failure, spironolactone
what medications in particular do you have to be careful with with digoxin
quinidine verapamil nifedipine amiodarone spironolactone
GI symptoms of digoxin toxicity
anorexia
nausea
vomiting
diarrhea, abdo pain are rare
CNS symptoms of digoxin toxicity
non specific
may have fatigue, weakness, insomnia, confusion, headache
can also have altered colour vision, usually yellow and green
CVS symptoms of digoxin toxicity
ARRHYTHMIAS–virtually all types
management of digoxin toxicity
do ABCs
STOP THE DRUG
hook up to telemetry
monitor K, Ca, Mg and correct if necessary
can try atropine for 2nd or 3rd degree AV block
can try lidocaine/phenytoin/MgSO4 for ventricular arrhythmia
