e impacted wisdom tooth is considered major surgery due to the expected difficulty of the surgery and the expected blood loss, particularly in subjects with type 2A or type 3 VWD. Extraction of more than two teeth is considered major surgery in all patients.
Major 100 IU/dL 80-100 IU/dL Δ* VWF:RCo × BW (kg)
IVR† = IU VWF:RCo required
If the IVR is not available, assume an IVR of 2.0 IU/dL per IU/kg and calculate the loading dose as follows:
(100 – baseline plasma VWF:RCo) × BW (kg) / 2.0
Minor/Oral‡ 50-60 IU/dL 40-50 IU/dL Δ* VWF:RCo × BW (kg)
IVR = IU VWF:RCo required
Emergency 100 IU/dL 80-100 IU/dL Administer a dose of 50-60 IU VWF:RCo/kg body weight.
For example, the loading dose of Humate-P required assuming a target VWF:RCo level of 100 International Units (IU)/dL, a baseline VWF:RCo level of 20 International Units (IU)/dL, an IVR of 2.0 International Units (IU)/dL per International Units (IU)/kg, and a body weight of 70 kg would be 2,800 International Units (IU) VWF:RCo, calculated as follows:
IU = International Units.
(100 IU/dL – 20 IU/dL) × 70 kg =2,800 IU VWF:RCo required
2.0 (IU/dL)/(IU/kg)
Attaining a target peak FVIII:C plasma level of 80 to 100 International Units (IU) FVIII:C/dL for major surgery and 40 to 50 International Units (IU) FVIII:C/dL for minor surgery or oral surgery might require additional dosing with Humate-P. Because the ratio of VWF:RCo to FVIII:C activity in Humate-P is 2.4:1, any additional dosing will increase VWF:RCo proportionally more than FVIII:C. Assuming an incremental IVR of 2.0 International Units (IU) VWF:RCo/dL per International Units (IU)/kg infused, additional dosing to increase FVIII:C in plasma will also increase plasma VWF:RCo by approximately 5 International Units (IU)/dL for each International Unit (IU)/kg of FVIII administered.
Maintenance Doses
The initial maintenance dose of Humate-P for the prevention of excessive bleeding during and after surgery should be half of the loading dose, irrespective of additional dosing required to meet FVIII:C targets. Subsequent maintenance doses should be based on the patient's VWF:RCo and FVIII levels. Table 4 provides recommendations for target trough plasma levels (based on type of surgery and number of days following surgery) and minimum duration of treatment for subsequent maintenance doses. These recommendations apply to both adult and pediatric patients.
Table 4: VWF:RCo and FVIII:C Target Trough Plasma Level and Minimum Duration of Treatment Recommendations for Subsequent Maintenance Doses for the Prevention of Excessive Bleeding During and After Surgery Type of Surgery VWF:RCo
Target Trough Plasma Level* FVIII:C
Target Trough Plasma Level* Minimum Duration of Treatment
Up to 3 days following surgery After Day 3 Up to 3 days following surgery After Day 3
IU = International Units.
*
Trough levels for either coagulation factor should not exceed 100 IU/dL.
†
Oral surgery is defined as extraction of fewer than three teeth, if the teeth are non-molars and have no bony involvement. Extraction of more than one impacted wisdom tooth is considered major surgery due to the expected difficulty of the surgery and the expected blood loss, particularly in subjects with type 2A or type 3 VWD. Extraction of more than two teeth is considered major surgery in all patients.
‡
Administer at least one maintenance dose following oral s |
