Cardiac glycosides Flashcards
1
Q
Cardiac glycosides
A
Digoxin: 75% bioavailability, 20-40% protein bound
t1/2=40 hrs, urinary excretion.
2
Q
MOA
A
Direct inhibition of Na+/K+ ATPase leading to indirect inhibition of Na+/Ca+ exchanger/antiport.
Increase Ca2+: positive inotropy, stimulates vegaus nerve to decreaseHR
3
Q
Use
A
CHF (increase contractility) Atrial fibrilation (low conductance at AV node and depression of SA node)
4
Q
Toxicity
A
Cholinergic: nausea, vomiting, diarrhea, blurry yellow vision
EKG: high PR, low QT, ST scooping, T wave inversion, arrhthmias, AV block
Can lead to Hyperkalemia, poor prognosis
5
Q
Factors predisposing to toxicity
A
Renal failure
Hypokalemia
Quinidine (decrease digoxin clearance; displae dogixin from tissue binding site)
6
Q
Antidote
A
Slowly normalizes K+
lidocaine, cardiac pacer, antiFab, Mg2+
