Infusion of Factor VIII-von Willebrand Factor concentrates results in a peak concentration that gradually declines until the next infusion is given.
(1) The decline in coagulant activity follows first order kinetics.
(2) The factors are primarily intravascular (so distribution volume is the plasma volume).
(1) minimum Factor VIII coagulant activity required (trough below next infusion) in IU/mL, as listed in previous section
(2) baseline Factor VIII coagulant activity prior to any therapy
(3) half-life of Factor VIII activity in hours
amount of Factor VIII activity that much be supplied at trough levels =
= (minimum activity required) - (baseline level) =
= (peak concentration) * EXP((-1) * k * (time in hours since last infusion))
= 0.693 / (half-life in hours)
peak concentration in IU/mL =
= ((minimum activity required) - (baseline level)) / EXP((-1) * 0.693 * (time since infusion) / (half-life in hours))
dose of Factor VIII coagulant activity to provide in IU =
= (peak concentration in IU/mL) * (plasma volume in mL)
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Specialty: Hematology Oncology, Clinical Laboratory, Clinical Laboratory, Clinical Pharmacology