- See: -
EKG Changes -
Interactions and Toxicities:
- Discussion: - for CHF,
A.fib, flutter, PAT; - digitalis is the only drug that slows ventricular response w/o decreasing myocardial contractility; *
Adult Dosing: * Loading: 0.25 - 0.5 PO/IV, then .25mg PO q6hr, until total dose = 1.0-1.5mg; * Note onset of action = 30min IV, 2hr PO; w/ normal Renal function: * Daily dose = 0.125- 0.5mg PO,IV,IM qd; * Theraputic Digoxin dose = 0.8 - 2.0 ng/ml; > than 2.4=toxic; * Theraputic Digitoxin dose = 13.0 - 25.0 ng/ml; > 40 is toxic;
- Use in A. Fib - onset of IV digoxin takes as long as 30 min. and peaks at 90-120 min - therefore, digoxin should not be given at intervals less than 2 hrs; - some patients may not slow with the initial 0.5 mg IV dose; - best indicator of successful of digitalization is ventricular rate; - w/
atrial fibrillation, digoxin is given until the rate is controlled to < 120;
- Precautions: (see
interactions) - w/
Digoxin Toxicity and
Hypo K may try 80 mEq KCl IV may be given in 1 liter of D5W at 6 ml/min (0.5 mEq/min); - initial therapy of toxicity related arrhythmias includes
LIDOCAINE &
dilantin; - calcium is contraindicated and
Cardioversion should be avoided;
- Peds: - Digitalization: 65-75 ug/kg PO or 50 ug/kg IV; 1/2 total dose initially then 1/4 of total q8-12hr for 2 doses; - Maintenance: 15-20 ug/kg/day PO divided q12hr; 2-10 yrs: - Digitalization: 30-40 ug/kg PO or 25 ug/kg IV given as above; - Maintenance: 8-10 ug/kg/day PO or divided q12hr;
