NAME OF DRUG
digoxin

CLASSIFICATION

Cardiac glycoside

ALTERNATE NAME

LANOXIN

INDICATIONS

• congestive heart failure, atrial fibrillation, atrial flutter, paroxysmal atrial tachycardia, cardiogenic shock

RECONSTITUTION AND STABILITY

• stable at room temperature
• do not use discoloured solutions

COMPATIBILITY

• incompatible with most other drugs
• compatible via Y site injection with hydrocortisone, potassium chloride, and vitamin B complex with C
• may be diluted in small volumes (5-10 mL) of D5W or NS for direct IV administration

ROUTES OF ADMINISTRATION

• IV direct 
  • may be administered through the tubing of a running I.V. over at least 1 to 5 minutes. (may be diluted with a four-fold volume of N.S. or D5W - proper dilution is required to avoid precipitation)
• IM 
  • NOT RECOMMENDED (absorption is delayed, unpredictable and irritating to tissue); exception:  when oral or I.V. routes are not feasible, inject deeply into the muscle followed by massage. No more than 0.5 mg into one site.

VH & HSC ADMINISTRATION POLICY

E - Direct IV can be administered by nurses on general nursing units provided a venous access has been established, and according to the policies and recommendations stated in this manual.

DOSAGE

NOTE: dosages are only averages and individual variations can be expected depending on response.

ADULT:

Digitalization

• 0.01-0.015 mg/kg of lean body weight divided into 2 or 3 equal parts and given at 6 hourly intervals

Maintenance

• 0.125-0.5 mg daily as a single or in divided doses

Dosage adjustments are necessary in patients with renal insufficiency

POTENTIAL HAZARDS OF PARENTERAL ADMINISTRATION

• extravasation may cause local irritation and sloughing

IMPORTANT IMPLICATIONS

• monitor the apical heart rate and blood pressure prior to each dose of digoxin
• notify the physician before the administration of subsequent doses of digoxin if there are any significant changes in heart rhythm, heart rate, or if there are any other signs of digitalis toxicity
• administer calcium cautiously in digitalized patients
• use with caution in patients with decreased serum potassium
• serum digoxin levels for CHF: 0.5-1 nmol/L; atrial fibrillation: 1-2.5 nmol/L
• blood specimens for levels should be drawn prior to the next dose (trough) or at least 8-12 hours after the last dose
• quinidine, verapamil and amiodarone will increase serum digoxin levels
• Symptoms of overdose:
  • Gastrointestinal 
    •  anorexia, nausea, vomiting, diarrhea, abdominal discomfort or pain
  • CNS 
    • headache, fatigue, malaise, drowsiness, muscle weakness, neuralgic pain, visual disturbances
  • Cardiac 
    • ventricular premature ectopic activity, paroxysmal and non-paroxysmal nodal rhythms, atrioventricular dissociation, paroxysmal tachycardia with block, and excessive slowing of the pulse (i.e. below 50 beats per minute in patients not on beta-blockers)
    • atrioventricular block of increasing degree may proceed to complete heart block

TREATMENT OF OVERDOSAGE:

• discontinue digoxin
• administer potassium salts and antiarrhythmics
• digoxin immune Fab (Digibind) - refer to monograph for indications

Rev. March 2006