What is the proper dosing of factor VIII (FVIII) concentrate for the treatment of hemophilia A?

Updated: Jan 14, 2019
  • Author: Douglass A Drelich, MD; Chief Editor: Srikanth Nagalla, MBBS, MS, FACP  more...
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Answer

Doses of FVIII concentrate are calculated according to the severity and location of bleeding. Guidelines for dosing are provided in Table 2 below. As a rule, FVIII 1 U/kg increases FVIII plasma levels by 2%. The reaction half-time is 8-12 hours. Target levels by hemorrhage severity are as follows:

  • Mild hemorrhages (ie, early hemarthrosis, epistaxis, gingival bleeding): Maintain an FVIII level of 30%

  • Major hemorrhages (ie, hemarthrosis or muscle bleeds with pain and swelling, prophylaxis after head trauma with negative findings on examination): Maintain an FVIII level of 50%

  • Life-threatening bleeding episodes (ie, major trauma or surgery, advanced or recurrent hemarthrosis): Maintain an FVIII level of 80-90%; after stabilization, maintain levels above 40-50% for a minimum of 7-10 days

Table 2. General Guidelines for Factor Replacement for the Treatment of Bleeding in Hemophilia (Open Table in a new window)

Indication or Site of Bleeding

Factor level Desired, %

FVIII Dose, IU/kg

Comment

Severe epistaxis; mouth, lip, tongue, or dental work

20-50

10-25

Consider aminocaproic acid (Amicar), 1-2 d

Joint (hip or groin)

40

20

Repeat transfusion in 24-48 h

Soft tissue or muscle

20-40

10-20

No therapy if site small and not enlarging (transfuse if enlarging)

Muscle (calf and forearm)

30-40

15-20

None

Muscle deep (thigh, hip, iliopsoas)

40-60

20-30

Transfuse, repeat at 24 h, then as needed

Neck or throat

50-80

25-40

None

Hematuria

40

20

Transfuse to 40% then rest and hydration

Laceration

40

20

Transfuse until wound healed

GI or retroperitoneal bleeding

60-80

30-40

None

Head trauma (no evidence of CNS bleeding)

50

25

None

Head trauma (probable or definite CNS bleeding, eg, headache, vomiting, neurologic signs)

100

50

Maintain peak and trough factor levels at 100% and 50% for 14 d if CNS bleeding documented

Trauma with bleeding, surgery

80-100

50

10-14 d

Variations in responses related to patient or product parameters make determinations of factor levels important. These determinations are performed immediately after infusions and thereafter to ensure an adequate response and maintenance levels. Obtain factor level assays daily before each infusion to establish a stable pattern of replacement regarding the dose and frequency of administration.


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