factor VIII(redirected from factor eight)
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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(1) The attribute of von Willebrand factor (vWF) required for platelet agglutination by ristocetin; there is no specific equivalent term, as the use of specific terminology for functional activities of vWF is not recommended by the Nomenclature Committee.
(2) Factor VIIIc—the functional attribute of factor VIII that is absent in factor-VIII deficiency (haemophilia A) and measured by standard coagulation techniques.
(3) Factor VIII (in current use)—the protein that is defective or absent in factor-VIII deficiency (haemophilia A).
factor VIIIAnti-hemophilic factor Hematology A heterotrimeric coagulation factor that forms a complex with factor IX, platelets, and calcium, thereby activating factor X; factor VIII is present in cryoprecipitated plasma, and is also used to treat hemophilia A; recombinant factor VIII–rF VIII therapy is used for hemophilia A
Synonym(s): antihemophilic factor A, antihemophilic globulin A, proserum prothrombin conversion accelerator.