GUIDELINES FOR CLOTTING FACTOR REPLACEMENT IN SEVERE HEMOPHILIA
A
(Modified from Pediatr Clin NA 1996;43:709-736) (see below for notes
regarding dosing in hemophilia B)
| SITE OF BLEED | TARGET FACTOR LEVEL | FACTOR DOSING | COMMENTS |
| Joint | 40-50% | 20-40 U/kg/day | Rest, immobilization, physical therapy |
| Muscle | 40-50% | 25-30 U/kg/day | Calf or forearm bleeds may be limb-threatening. Femoral or retroperitoneal bleeds may cause significant blood loss |
| Oral mucosa | Initially 50%, then antifibrinolytic Rx until healed | 25 U/kg/day | Adjuvant antifibrinolytic Rx (Amicar) |
| Epistaxis | Initially 80-100%, then 30% until healed | 40-50 U/kg, then 30-40 U/kg/day |
Pressure; packing and cautery for severe/ recurrent bleed |
| Gastrointestinal | Initially 100%, then 30% until healed | 40-50 U/kg, then 30-40 U/kg/day |
Endoscopy (lesion often found) Antifibrinolytic Rx |
| Genitourinary | Initially 100%, then 30% until healed | 40-50 U/kg, then 30-40 U/kg/day |
R/O stone, UTI Consider adjuvant prednisone 1-2 mg/kg/day x 5-7 d |
| CNS | Initially 100%, then 50-100% x 10-14 d |
50 U/kg, then 25 U/kg/12 or by continuous infusion | Consider prophylactic anticonvulsants.
LP requires prophylactic infusion |
| Trauma or Surgery | Initially 100%, then 50% until wound healing begins, then 30% until healing complete |
50 U/kg, then dose q12h or by continuous infusion | Evaluate for inhibitor prior to elective surgery |
See also Furie
et al, Blood 1994;84:3-9
Factor VIII level will increase by approximately 2% for every unit of
clotting factor per kg body weight. Factor VIII half-life is 8-12 hours.
When the goal is to maintain factor levels above a threshold for more than
a day, Factor VIII should be given every 12 hours, or by continuous infusion.
Factor levels should be drawn near the end of a dosing period. If recovery
of factor is substantially less than expected, consider the possibility
of a factor VIII inhibitor. [Note: recombinant factor VIII concentrates
may give lower-than-expected recovery, typically about 80% of expected.]
Please notify the special coagulation lab (3-5005) in advance if
you anticipate ordering factor VIII or IX levels at night or on weekends.
Factor IX has longer half-life (18-24 hours) but greater volume of distribution,
so factor level increases by only 1% per unit of clotting factor per kg
body weight. The net effect is that steady-state dosing is approximately
the same as for factor VIII, although initial doses need to be somewhat
higher. Recombinant factor IX concentrates may require somewhat higher
dosing than plasma-derived concentrates to achieve comparable blood levels.
Factor IX concentrate should be given every 12-24 hours.
The UWHC Comprehensive Program For Bleeding Disorders (608-890-9493)
can facilitate delivery of clotting factor concentrates for home use, and
provide general assistance in the outpatient management of patients with
hemophilia.