Protocols - Hemorio

PHARMACOKINETICS OF CLOTTING FACTORS: the pharmacokinetics study of concentrate factor to
be used must be performed within an interval of one week to 3 days before surgery. ISTH recommends
the study to be performed with 30 IU/kg only dose infusion and serial sample draws for dosage of infused
factor activity level. The first sample is pre-infusion, followed by 8 more samples drawn from the arm not
infused, to determine the maximum peak of factor level, considering at least 3 samples post-infusion. Reusage
is given by the factor activity in these 3 samples and it is expressed in % by the formula (ml/kg/h) =
infusion index (IU/kg/h) / plasma level (lU/ml).
METHOD: One FVIII dose in “bolus” is infused on pre-operatory. This dose is calculated to reach plasma
levels between 60-80%. The continuous infusion starts right after the end of surgery or even during it. The
dose administered is based on clearance obtained by the pharmacokinetics study according to the
formula: FVIII level post- and pre-infusion X weight (Kg) / Factor dose given in IU.
NOTES: PTTa or FVIII dosage must be performed 4-6 hours after surgery to confirm if the dose is
sufficient. Clearance is calculated every day, based on FVIII day activity to adjust the infusion and
therefore, reach the desirable FVIII levels. For major surgery, the minimum desirable level is 50 and 30%
during the 1 st week and 2 nd week, respectively.
In case of emergency surgery or major bleeding, the “bolus” dose is the same for elective surgeries and
the continuous infusion must be installed immediately after the “bolus” dose.
When the pharmacokinetics study is not possible, it may be administered on the 1st infusion of 2 to
4IU/kg/h depending on the surgery or bleeding. In the next day, a sample is drawn to dose the factor
plasma level and establish continuity.
Overall, it is noted a decreased amount of factor required to keep the same plasma level.
DOMICILE DOSE PROGRAM
Intervention in the hemorrhage episode in hemophilia carriers, reaches its maximum efficiency with
immediate access to the clotting factor, limiting the bleeding and the extension of resulting tissue damage.
Early replacement therapy decreased the amount of clotting factor required to control the bleeding
situation. The Domicile Dose Program aims to offer eligible hemophilia patients, 3 doses of clotting factor
concentrate which increases the plasma level to 40%, for self-infusion at home, allowing early drug
therapy. Thus, it reduces the “stress” arising from the need to go get the specific assistance to the drug
and also allows the patient to participate in an active manner in his/her treatment.
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