USUAL DOSE (International units [IU])
Prophylactic vaccinations recommended; see Patient Education.
One IU of von Willebrand factor:Ristocetin Cofactor (VWF:RCo) is approximately equal to the level of VWF:RCo activity found in 1 mL of fresh human plasma. The ratio between VWF:RCo and FVIII activities in Wilate is approximately 1:1. When using a FVIII-containing VWF product, continued treatment may cause an excessive rise in FVIII activity; see Monitor.
Calculate the required dose using the following formula:
Required IU = Body weight (kg) × Desired VWF:RCo rise (%) (IU/dL) × 0.5 (IU/kg per IU/dL)
Adjust dose and frequency of administration according to the clinical effectiveness in each patient. The following chart provides estimated doses for minor and major hemorrhages.
aMaintenance doses may need to be continued for up to 3 days for minor hemorrhages and 5 to 7 days for major hemorrhages. Repeat doses may be administered for as long as needed based on repeated monitoring of appropriate clinical and laboratory measures. | ||||||||||||||||
Recommendations for dosing in minor and major surgeries is provided in the following chart.
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See prescribing information for an alternate formula to determine loading dose based on patient’s individual in vivo recovery (IVR) determined before surgery.
Performing appropriate lab tests once a day after surgery is recommended to ensure adequate VWF:RCo and FVIII activity levels are reached and maintained. To decrease the risk of perioperative thrombosis, FVIII activity levels should not exceed 250%.
Follow the general recommendations for dosing and administration for adults. See Usual Dose and Maternal/Child.
Adjust dose according to the extent and location of bleeding and the patient’s clinical condition.
■ vWD Type 3 patients with GI bleeding may require higher doses.
DILUTION (International units [IU])
Available in 5-mL and 10-mL vials containing either 500 or 1,000 IU VWF:RCo and 500 or 1,000 IU FVIII activities. Provided as a kit containing a single-dose vial of powder, a vial of diluent, a Mix2Vial transfer device, a 10-mL syringe, an infusion set, and 2 alcohol swabs. Consult instructions for reconstitution and injection in the package insert. Warm to room temperature (25° C) before dilution and maintain throughout reconstitution. If a water bath is used for warming (temperature should not exceed 37° C [98° F]), do not allow water to come into contact with the latex-free rubber stopper or vial caps. The total number of IUs available is clearly marked on each vial. Record the batch number of each vial. Should be used immediately after reconstitution. Solution should be clear or slightly opalescent.
Incorporated into the Mix2Vial.
Store in original carton to protect from light. Stable for 36 months from date of manufacture when refrigerated at 2° to 8° C (36° to 46° F). Do not freeze. May be stored at RT (maximum of 25° C [77° F]) for up to 6 months. Label vial with date removed from refrigeration. Once stored at RT, do not return to refrigeration. Shelf life expires 6 months from date of removal from refrigeration or on the expiration date on the product vial, whichever is earlier. Administer immediately after reconstitution. Discard any unused solution.
Manufacturer states, “Must not be mixed with other medicinal products or administered simultaneously with other IV preparations in the same infusion set.”
A single dose as an infusion at 2 to 4 mL/min. Reduce rate of administration or interrupt the infusion if a marked increase in pulse occurs.
A purified, lyophilized von Willebrand factor (VWF) and coagulation factor VIII complex that is obtained from pooled human plasma. VWF and FVIII are normal constituents of human plasma. Patients with VWD have a deficiency or abnormality of VWF; this results in low FVIII activity and an abnormal platelet function, which causes excessive bleeding. VWF promotes platelet aggregation and platelet adhesion on damaged vascular endothelium; it also serves as a stabilizing carrier protein for the procoagulant protein FVIII, an essential cofactor in the activation of factor X, leading to the formation of thrombin and fibrin. VWF activity is measured with an assay that uses an agglutinating cofactor called Ristocetin (RCo). The VWF:RCo assay provides a quantitative measurement of VWF function by determining how well VWF helps platelets adhere to one another. Reduced VWF:RCo activity indicates a deficiency of VWF. Half-life varies based on type of VWD (1, 2, or 3).
On-demand treatment and control of bleeding episodes and perioperative management of bleeding in pediatric patients and adults with von Willebrand disease.
Not indicated for the treatment of hemophilia A.
History of anaphylactic or severe systemic reactions to plasma-derived products, any ingredient in the formulation, or components of the container.
For IV use only.
■ Administered under the direction of a physician knowledgeable in the treatment of coagulation disorders in a facility with adequate diagnostic and treatment facilities to monitor the patient and respond to any medical emergency.
■ Hypersensitivity reactions, including anaphylaxis, have occurred; see Monitor.
■ Manufactured from human plasma. Risk of transmitting infectious agents (e.g., HIV, hepatitis and, theoretically, Creutzfeldt-Jakob disease) has been greatly reduced by screening, testing, and manufacturing techniques. However, risk of transmission cannot be totally eliminated.
■ Hepatitis A and B vaccines are recommended for patients receiving plasma derivatives.
■ Thrombotic events have been reported. Use caution in patients with known risk factors for thrombosis.
■ Inhibitors may develop with large or frequent doses; see Monitor.
Monitor BP and pulse during infusion. If a marked increase in pulse occurs, either reduce rate of infusion or interrupt the infusion.
■ Throughout the infusion, monitor for S/S of a hypersensitivity reaction (e.g., angioedema, burning and stinging at injection site, chills, fever, flushing, headache, hives, hypotension, nausea, tachycardia, tightness of the chest, urticaria, vomiting, wheezing). Evaluate for the presence of inhibitors if an anaphylactic reaction occurs.
■ Appropriate laboratory tests should be performed on the patient’s plasma at suitable intervals to ensure that adequate VWF:RCo and FVIII activity levels have been reached and are maintained. Monitoring is also required to avoid sustained excessive VWF and FVIII activity. When using a VWF product that contains FVIII, continued treatment may cause an excessive rise in FVIII activity. Excessive activity levels may increase the risk of thrombotic events. In the postsurgery period, monitoring should be done daily if possible, and FVIII levels should not exceed 250%.
■ Monitor for development of VWF and FVIII inhibitors (neutralizing antibodies). Consider formation of inhibitors and perform assays if bleeding is not controlled with usual doses.
Review manufacturer’s medication guide.
■ Prophylactic hepatitis A and hepatitis B vaccines recommended.
■ Promptly report S/S of a hypersensitivity reaction (e.g., dizziness, hives, itching, rash, tightness of the chest).
■ Frequent blood tests (e.g., monitoring of VWF:RCo and FVIII activity) are required to ensure effectiveness and reduce the risk of thrombotic events.
■ Inhibitors may develop if expected VWF activity plasma levels are not attained or if bleeding is not controlled with adequate or repeat dosing; notify treating physician.
■ Report symptoms of possibly transmitted viral infections immediately. Symptoms may include anorexia, arthralgias, fatigue, jaundice, low-grade fever, nausea, or vomiting.
Use during pregnancy or labor and delivery only if clearly needed.
■ Safety for use during breast-feeding is unknown; consider benefit versus risk.
■ Approved for use in pediatric patients. No dose adjustment is required.
Numbers insufficient to determine differences in response compared with younger adults.
The most common side effects reported are dizziness, hypersensitivity reactions, and urticaria. The most serious adverse reactions were hypersensitivity reactions.
Abdominal pain, anaphylactic reaction, chest discomfort, chills, cough, dyspnea, factor VIII inhibition, fever, flushing, headache, hypotension, nausea, paresthesia, rash, tachycardia, and vomiting.
Keep the physician informed of side effects. Slow or interrupt infusion for a marked increase in pulse rate or mild hypersensitivity reaction. Discontinue the infusion immediately if a severe hypersensitivity reaction or thrombotic event (e.g., chest pain, dyspnea, leg pain, MI) occurs, and evaluate for the presence of inhibitors. Treat hypersensitivity as necessary (e.g., antihistamines, epinephrine, corticosteroids), and treat thrombotic events with appropriate measures. Resuscitate as necessary.