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antihemophilic factor (AHF, factor VIII)
Pharmacologic class: Hemostatic
Therapeutic class: Antihemophilic
Pregnancy risk category C
FDA Box Warning
• Drug is made from human plasma and may contain infectious agents. Plasma donor screening, testing, and inactivation or removal methods reduce this risk.
Promotes conversion of prothrombin to thrombin (necessary for hemostasis and blood clotting). Also replaces missing or deficient clotting factors, thereby controlling or preventing bleeding.
I.V. injection: 250, 500, 1,000, or 1,500 international units/vial in numerous preparations
Indications and dosages
➣ Spontaneous hemorrhage in patients with hemophilia A (factor VIII deficiency)
Adults and children: Dosage is highly individualized, calculated as follows: AHF required (international units) equals weight (kg) multiplied by desired factor VIII increase (% of normal) multiplied by 0.5.
To control bleeding, desired factor VIII level is 20% to 40% of normal for minor hemorrhage; 30% to 60% of normal for moderate hemorrhage; or 60% to 100% of normal for severe hemorrhage. To prevent spontaneous hemorrhage, desired factor VIII level is 5% of normal.
• Hypersensitivity to drug or to mouse, hamster, or bovine protein
Use cautiously in:
• hepatic disease
• blood types A, B, and AB
• patients receiving factor VIII inhibitors
• pregnant patients
• neonates and infants.
• Before giving, verify that patient has no history of hypersensitivity to drug or to mouse, hamster, or bovine protein.
• Follow prescriber's instructions regarding hepatitis B prophylaxis before starting therapy.
• Refrigerate concentrate until ready to reconstitute drug; then warm to room temperature before mixing.
• Roll bottle gently between hands until drug is well-mixed.
• Give a single dose over 5 to 10 minutes at rate of 2 to 10 ml/minute, as appropriate.
• After drug is reconstituted, don't refrigerate, shake, or store near heat.
• Don't mix with other I.V. solutions.
• Use plastic (not glass) syringe and filter.
CNS: headache; lethargy; fatigue; dizziness; jitteriness; drowsiness; depersonalization; tingling in arms, ears, and face
CV: chest tightness, angina pectoris, tachycardia, slight hypotension, thrombosis
EENT: blurred or abnormal vision, eye disorder, otitis media, epistaxis, rhinitis, sore throat
GI: nausea, vomiting, diarrhea, constipation, stomachache, abdominal pain, gastroenteritis, anorexia,
Hematologic: forehead bruises, increased bleeding tendency, thrombocytopenia, hemolytic anemia, intravascular hemolysis, hyperfibrinogenemia
Hepatic: hepatitis B transmission Musculoskeletal: myalgia, muscle weakness, bone pain, finger pain
Respiratory: dyspnea, coughing, wheezing, bronchospasm
Skin: rash, acne, flushing, diaphoresis, urticaria
Other: taste changes, allergic reaction, fever, chills, cold feet, cold sensations, infected hematoma, stinging at injection site, anaphylaxis, human immunodeficiency virus transmission
Drug-diagnostic tests. Bilirubin, creatine kinase: increased levels
Hemoglobin, platelets: decreased values
☞ Monitor for signs and symptoms of anaphylaxis and hemolysis.
☞ Watch for bleeding tendency and hemorrhaging.
• Check vital signs regularly.
• Monitor CBC and coagulation studies.
☞ Assess for severe headache (may indicate intracranial hemorrhage).
☞ Tell patient to immediately report signs and symptoms of allergic response or bleeding tendency.
• Caution patient not to use aspirin during therapy.
• Instruct patient to contact prescriber if drug becomes less effective.
• Tell patient to report signs or symptoms of hepatitis B.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, alertness, and vision.
• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.
• Notify patient that he'll undergo regular blood testing during therapy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.
factor VIII(trade name),
Helixate FS(trade name),
Helixate NexGen(trade name),
Kogenate FS(trade name),
ClassificationTherapeutic: hemostatic agents
Pharmacologic: blood products
Time/action profile (levels of factor VIII)
|IV||rapid||1–2 hr||8–12 hr|
Adverse Reactions/Side Effects
Central nervous system
- loss of consciousness
Ear, Eye, Nose, Throat
- visual disturbances
- chest tightness
- intravascular hemolysis
- postoperative hemorrhage
- back pain
- allergic reactions
- hepatitis B, C, D, or HIV virus infection (small risk from frequent use of large amounts)
Drug-Drug interactionNone significant.
Route/DosageRecommended doses vary from product to product. Consult individual product information for more specific dosing information. Dose may be calculated using the following formula: Dose AHF (units) = body weight (kg) × desired AHF increase (% normal) × 0.5. Each unit of AHF/kg may be expected to produce a 2% rise in factor VIII activityPrevention of Spontaneous Hemorrhage
- Monitor BP, pulse, and respirations. If tachycardia occurs, slow or stop infusion rate and notify health care professional.
- Obtain history of current trauma; estimate amount of blood loss.
- Monitor for renewed bleeding every 15–30 min. Immobilize and apply ice to affected joints.
- Monitor intake and output ratios; note color of urine. Notify health care professional of significant discrepancy or if urine becomes red or orange. Patients with types A, B, and AB blood are particularly at risk for hemolytic reaction.
- Assess for allergic reaction (wheezing, tachycardia, urticaria, hives, chest tightness, stinging at IV site, nausea and vomiting, lethargy). Diphenhydramine (Benadryl) may be used as a premedication to prevent acute reactions. Stop infusion, notify health care professional.
- Lab Test Considerations: Monitor plasma factor VIII levels. To prevent spontaneous bleeding, at least 5% of the normal factor VIII level must be present.
- Obtain baseline and periodic results of CBC, platelet count, direct Coombs’ test, urinalysis, partial thromboplastin time (PTT), thromboplastin generation test, and prothrombin generation test. ↓ hematocrit and ↑ Coombs’ test may indicate hemolytic anemia.
- Monitor coagulation studies before, during, and after therapy to assess effectiveness of therapy.
- Patients with ↑ inhibitor levels may not respond or may require ↑ doses.
Potential Nursing DiagnosesIneffective tissue perfusion (Indications)
Risk for injury (Indications)
- Inform all personnel of bleeding tendency. Apply pressure to venipuncture sites for at least 5 min; avoid unnecessary IM injections.
- Dose varies with degree of clotting factor deficit, desired level of clotting factors, and weight.
- Obtain type and crossmatch of blood in case a transfusion is necessary.
- The first dose of AHF is given 1 hr before surgery.
- Administer IV only. Refrigerate concentrate until just before reconstitution. Warm concentrate and diluent (provided by manufacturer) to room temperature before reconstituting. Use plastic syringe for preparation and administration. Use an additional needle as an air vent to the vial when reconstituting. After adding diluent, rotate vial gently until completely dissolved. Solution may vary in color from light yellow to clear with a bluish tint. Do not refrigerate after reconstitution; use within 3 hr. Preparations should be filtered before administration.
- Rate: Rate is based on patient’s response. Administer at a rate of 2 mL/min. May be given over up to 10 min.
- Y-Site/Additive Incompatibility: Do not admix or administer in the same line with any other medication or solution.
- Instruct patient to notify health care professional immediately if bleeding recurs. Advise patient to observe for bleeding in gums, skin, urine, stool, or emesis.
- Inform patient inhibitor formation may occur with treatment of hemophilia A. Advise patient to contact their health care professional if they experience lack of clinical response to Factor VIII replacement therapy; may be manifestation of an inhibitor.
- Caution patient to avoid products containing aspirin or NSAIDs; they may further impair clotting.
- Review prevention of bleeding with patient (use soft toothbrush, avoid IM and subcut injections, avoid potentially traumatic activities).
- Inform newly diagnosed hemophilia patients of the need for hepatitis B vaccine. Advise patient that the risk of hepatitis or AIDS transmission may be diminished by the use of heat-treated, pasteurized, solvent/detergent-treated, or monoclonal antibody preparations. Screening programs should also decrease the risk.
- Advise patients to consult health care professional prior to travel. While traveling advise patients to bring an adequate supply of AHF based on their current treatment regimen.
- Advise patient to carry identification describing disease process at all times.
- Prevention of spontaneous bleeding.
- Cessation of bleeding.
- Decrease bleeding and risk of joint damage in children with hemophilia A who have no pre-existing joint damage.
- Prevention or reduction of frequency of bleeding episodes in adults and children with hemophilia A.