| Digoxin: |
Cardiac Glycoside |
|
|
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Used for CHRONIC A Fib/A Flutter in patients who ALSO have CHF. Not a first line drug in an emergent situation, but can be used to controll ventricular response in A Fib/Flutter and PSVT.
|
DOSING |
| 0.25 mg |
To load the blood, give SLOW IV over 5 minutes Q6 hours x 4 doses. Giving this stuff too fast causes coronary and systemic vasoconstriction (that's bad)!!! |
|
0.125-0.5 mg |
This is the range for the routine DAILY maintainance dosage, However, 0.5 mg would be a hell of a lot! |
Digoxin
promotes the influx of Ca++ across cell membranes by inhibiting
sodium-potassium activated ATPase, creating a positive inotropic effect, while
simultaneously lowering HR by activity in the CNS to increase vagal tone, and
slow conduction through the SA and AV node.
It is used primarily for patients with chronic atrial fib/flutter who
also have CHF.
Can also been used in the treatment of PSVT, but again, primarily in
those who have CHF (EF <40%).
Other drugs are preffered these days.
It is the only inotrope available in the US in an
oral form.
Side
Effects: Arrhythmias associated with ¯conduction,
VT, PVCs, especially with ¯
K+.
¯
BP, ¯
HR, fatigue, weakness, anorexia, N/V, diarrhea, HA, mental status changes,
psychosis, seizures, visual disturbances (many, including the yellow/green
halos), messenteric ischemia/infection. Toxicity results from an overload of Ca++,
causing delayed afterdepolarizations (DADs), and
atrial and ventricular arrhythmias.
vagal stimulation causes PAT with block.
¯
K+ enhances toxic effects.
Contraindicated:
VF/VT. Use
caution in patients with renal failure. Hold for HR <60.
A
lot of drugs interact with digoxin to either increase or decrease serum
levels.
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