Digoxin Immune Fab

From Anvita Health Wiki

Contents 1 Introduction 2 Indications 3 Dosage 4 Pharmacokinetics 5 Adverse-effects 6 Drug-interactions 7 Mechanism-of-action 8 More General Terms 9 References

Introduction

• Tradename: Digibind.

Indications

• adjunctive therapy for life-threatening or potentially life-threatening digoxin or digitoxin toxicity
• oleander toxicity

Dosage

• Digoxin toxicity 2-20 vials IV over 15-30 minutes
• 40 mg of Digibind binds approximately 0.6 mg of glycoside

• Injection: 38-40 mg/vial.
  
• TBL: total body load of digoxin in mg
• C: measured serum concentration in ng/mL
  
• TBL = C x 5.6 x body weight (kg)/1000
  
• Digibind dose (mg) = TBL x 76
  Digibind dose (vials) = C ( ng/mL) x weight (kg)/100
  

Pharmacokinetics

• peak concentrations occur at the completion of infusion
• free (unbound) glycoside concentrations decline within 15-30 minutes
• measure serum concentrations of digoxin may increase 10-20 fold, but don't correlated with free dixogin
• eliminated in the urine
• elimination 1/2life is 12-20 hours
  

• elimination via kidney
• 1/2life = 12-20 hours

Adverse-effects

• hyperkalemia

• due to extracellular shifts of K+
• patient may actually be total body K+ depleted
• K+ levels return to normal in 4-6 hours

• allergic reactions

Drug-interactions

• digoxin: do not attempt to redigitalize for 2-3 days, or for 5-7 days if evidence of renal insufficiency

Mechanism-of-action

• high-affinity, specific antigen-binding fragments bind free (unbound) digoxin or digitoxin
• blocks & reverses inhibition of Na+/K+ ATPase

More General Terms

• Fab fragment
• antidote

References

1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
4. Department of Veterans Affairs, VA National Formulary

digoxin immune Fab (Digibind)