Factor VIII Indications & Dosing for adults

The hemophilic conditions are a group of related inherited bleeding disorders and include abnormalities of coagulation factors as well as platelet function

General Dosing Recommendation:

INDICATION	% OF NORMAL	DOSE
Minor hemorrhage	~20% to 40%	·      10-20 units/kg as a single dose ·      Mild superficial or early hemorrhages may respond to a single dose; ·      may repeat dose every 12-24 hours for 1-3 days until bleeding is resolved or healing achieved
Moderate hemorrhage/minor surgery	30% to 50%	·      15-25 units/kg ·      If needed, may continue with a maintenance dose of 10-15 units/kg every 8-12 hours.
Major to life-threatening hemorrhage	80% to 100%	·      Initial dose 40-50 units/kg ·      followed by a maintenance dose of 20-25 units/kg every 8-12 hours until threat is resolved
Major surgery	100% before surgery	·      50 units/kg given preoperatively ·      May repeat as necessary after 6-12 hours initially and for a total of 10-14 days until healing is complete. ·      Intensity of therapy may depend on type of surgery and postoperative regime
Bleeding prophylaxis		·      May be administered on a regular basis for bleeding prophylaxis. ·      Doses of 24-40 units/kg 3 times/week have been reported in patients with severe hemophilia to prevent joint bleeding

 

 Dosage based on desired factor VIII increase (%):

To calculate dosage needed based on desired factor VIII increase (%):

Body weight (kg) x 0.5 units/kg x desired factor VIII increase (%) = units factor VIII required

For example:

50 kg x 0.5 units/kg x 30 (% increase) = 750 units factor VIII 

Dosage based on expected factor VIII increase (%):

It is also possible to calculate the expected % factor VIII increase:

(# units administered x 2%/units/kg) divided by body weight (kg) = expected % factor VIII increase

For example:

(1400 units x 2%/units/kg) divided by 70 kg = 40%

references:
1. www.uptodate.com
2. lexicomp