10:6 rule in Dig toxicity

Q: What is the rule of 10:6 in digoxin toxicity?

Answer:

The 'rule of 10:6 is easy to remember and may be helpful while ordering Digoxin immune Fab (digibind, DigiFab) in patients with digoxin toxicity.

• If an unknown amount is acutely ingested, 10 vials can be administered; an additional 10 vials can be given if necessary.
• In chronic digoxin therapy, where toxicity is suspected, 6 vials are usually sufficient to resolve symptoms.

If required, the digibind dose can be calculated by using the formula:

number of vials = (digoxin concentration) x (patient's weight) / 100

EKG changes are the best way to monitor resolution. Resolution may be visible within 30 minutes, but it takes 2-4 hours to take full effect. 

Each vial of DigiFab contains 40 mg of Fab, which binds 0.5 mg of digoxin. DigiFab is usually given in an IV preparation over 30 minutes, but an IV push can be given in life-threatening situations. It may cause some febrile reactions. It should be avoided in patients with an allergy to sheep protein and papaya extracts.

#toxicity

# pharmacology

Recommended readings:

1. Wei S, Niu MT, Dores GM. Adverse Events Associated with Use of Digoxin Immune Fab Reported to the US Food and Drug Administration Adverse Event Reporting System, 1986-2019. Drugs Real World Outcomes. 2021 Jun;8(2):253-262. doi: 10.1007/s40801-021-00242-x. Epub 2021 Mar 15. PMID: 33721285; PMCID: PMC8128941.

2. Ip D, Syed H, Cohen M. Digoxin specific antibody fragments (Digibind) in digoxin toxicity. BMJ. 2009 Sep 3;339:b2884. doi: 10.1136/bmj.b2884. PMID: 19729422.

3. Lucyk S. Calculated decisions: DigiFab® (Digibind®) Dosing for Digoxin Poisoning. Emerg Med Pract. 2020 Sep 15;22(Suppl 9):CD1-CD3. PMID: 33476509.