Treatment should be conducted under the supervision of a physician with experience in managing patients with hemophilia.
Dosage and duration of substitution therapy depend on the degree of FVIII deficiency, localization and intensity of bleeding, as well as on the severity of the clinical condition of the patient.
The amount of FVIII administered is expressed in International Units (ME), which corresponds to the generally accepted standard of the World Health Organization (WHO) for preparations of factor VIII. Plasma FVIII activity is expressed either as a percentage (corresponds to normal human plasma) or in International Units (corresponding to the International Standard for FVIII in plasma).
One International Unit (ME) activity of vVIII is equal to the amount of vVIII in 1 ml of normal human plasma.
The calculation of the required dose of FVIII is based on empirical evidence that one International UnitME) FVIII per kg of body weight increases the activity of FVIII in plasma by 2.1 ± 0.4%.
The dose of the drug is calculated by the formula:
Required dose of Fundy® = body weight (kg) x desired increase in FVIII (%) (ME / dL) x 0.5
In each specific case, the total dose and frequency of drug administration should always be correlated with clinical efficacy.
In the following cases of bleeding, the activity of FVIII should not fall below this level of plasma activity (in% of the norm or in IU / dL) in the relevant period. The following table can be used for the recommended dosage for bleeding and surgical interventions:
| Severity of bleeding / Type of surgical intervention | Required activity level fVIII in blood (%) (IU / dl) | Frequency of administration (h) / Duration of therapy (days) |
| Bleeding |
|
|
| Beginning hemarthrosis, hemorrhage into soft tissues or bleeding of the oral mucosa | 20-40 | Every 12-24 hours (at least 1 day before the bleeding stops (or its pain manifestation) or until the wound is healed. |
| More severe hemarthrosis bleeding or soft tissue hematoma | 30-60 | Repeat every 12-24 hours for 3-4 or more days until the pain or disability ceases. |
| Life-threatening hemorrhages and hemorrhages | 60-100 | Repeat every 8-24 hours until the threat is eliminated. |
| Surgical interventions |
|
|
| Small surgical interventions, including tooth extraction | 30-60 | Every 24 hours (at least 1 day) until the wound is completely healed. |
| Large surgical interventions | 80-100 (pre- and post-operation) | Repeat every 8-24 hours until the wound is healed, then continue therapy for a minimum of 7 days, maintaining FVIII at 30-60% (IU / dl). |
During the course of treatment it is recommended to determine the activity of FVIII for correcting the dose of the drug and the frequency of its administration. In the case of large surgical interventions, accurate monitoring of replacement therapy is particularly needed, which implies the study of the coagulogram and activity of FVIII. Individual patients may differ in the clinical response to the administration of FVIII and demonstrate a different level of elevation of factor VIII under conditions in vivo and its half-life.
For the long-term prophylaxis of bleeding in patients with severe hemophilia A, the usual doses range from 20 to 40 ME factor VIII per kg of body weight every 2-3 days. In some cases, especially in young patients, smaller intervals between administrations or larger doses may be required.
There is insufficient clinical data on the use of Fundy® in children under 6 years.
Patients should be screened regularly to identify inhibitors to FVIII. If the expected increase in plasma fVIII activity is not achieved or the bleeding is not controlled by the appropriate dose, it is necessary to conduct a test for inhibitors to FVIII. In patients with a high level of inhibitor, the substitution therapy for FVIII may be ineffective and then other therapeutic options should be considered. Assistance to such patients should be provided by physicians with experience in the treatment of patients with hemophilia.
Method of preparing a solution for infusions
The chemical and physical stability of the preparation during its use is maintained for 12 hours at a temperature of 25 ° C. From the microbiological point of view, the drug must be used immediately. If the drug is not used immediately, the period and conditions for its storage before use (if the recovery is not carried out in controlled andapproved aseptic conditions) is determined by the user and usually does not exceed 24 h at a temperature of 2 to 8 ° C. Unused residues of the drug can not be stored for later use and stored in the refrigerator.
Preparation of the solution:
1. Heat the vial with the lyophilizate and the syringe with the solvent to a temperature no higher than 30 ° C (Fig. 1).
2. Insert the plunger into the syringe containing the solvent (Fig. 2).
3. Remove the filter from the packaging. Remove the cap from the end of the syringe and fix the filter on the syringe (Figure 3).
4. Take the adapter out of the package to the vial and fix it on the syringe with the filter (Figure 4).
5. Remove the lid of the vial with the drug and treat the cork with an aseptic tampon (Fig. 5).
6. Puncture the plug with the adapter needle (Fig. 6).
7. Pour the solvent completely from the syringe into the vial (Fig. 7).
8. Carefully rotate the vial until the drug dissolves completely. Do not use the drug until the drug has dissolved completely or while mechanical particles are visible (Fig. 8).
The reconstituted solution must be clear or slightly opalescent, colorless or light yellow, with no visible foreign matter.
Do not use the solution if there is a flocculent deposit or mechanical inclusions.
Before use, the reconstituted preparation must be visually inspected for presence of solid particles and for discoloration.
9. Quickly separate the syringe with the filter from the vial with the adapter, to avoid air ingress (Fig. 9).
10. Turn the bottle over and move the prepared solution into the syringe (Figure 10).
11. Prepare the injection site, separate the syringe and enter the medication with the supplied sterile "butterfly" needle or other sterile needle. The rate of infusion into the vein should be 3 ml / min and not exceed 10 ml / min (Figure 11).
Do not reuse infusion sets.
Any unused product or other used materials should be disposed of in accordance with local requirements.