Digitalis (Digoxin)

Treatment of CHF, atrial fibrillation, and flutter.

Prevention of supraventricular arrhythmias following thoracotomy (controversial).

Cardiac side effects: Arrhythmias and conduction disturbances.

Noncardiac side effects: GI—anorexia, N/V, and abdominal pain; CNS—visual disturbances, headache, drowsiness, and confusion.

Recent systematic review and meta-analysis suggest that use of digoxin is associated with increased mortality risk, especially in pts with atrial fibrillation.

Cardiac arrhythmia (toxicity) can be precipitated by hypokalemia, hypomagnesemia, hypoxia, hypercalcemia, hypernatremia, and renal failure.

DC cardioversion can cause severe ventricular arrhythmias in pts with toxic levels.

AV block (with co-administration of β-adrenergic, Ca ²⁺ -channel blocking drugs).

Dosing has a narrow therapeutic index (0.8–2 ng/mL or 1.2–2 nmol/L).

Avoid in pts with ventricular extrasystole or VT, as it may precipitate VF due to increased cardiac excitability.

Hyperventilation can cause alkalosis leading to relative hypokalemia toxicity.

Renal insufficiency (decreased digoxin clearance and need for dose alteration, not appreciably removed by dialysis).