factor VIII (redirected from Factor viiia)

factor VIII

n.

A factor in the clotting of blood, a deficiency of which is associated with hemophilia A. Also called antihemophilic factor, antihemophilic globulin, antihemophilic globulin A, proserum prothrombin conversion accelerator.

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Factor VIII

A protein involved in blood clotting that requires vWF for stability and long-term survival in the bloodstream.

Mentioned in: Von Willebrand Disease

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antihemophilic factor (AHF, factor VIII)

Alphanate, Hemofil M, Koate-DVI, Kogenate FS, Monarc-M, Monoclate-P, Recombinate, ReFacto

Pharmacologic class: Hemostatic

Therapeutic class: Antihemophilic

Pregnancy risk category C

FDA Boxed Warning

• Drug is made from human plasma and may contain infectious agents. Plasma donor screening, testing, and inactivation or removal methods reduce this risk.

Action

Promotes conversion of prothrombin to thrombin (necessary for hemostasis and blood clotting). Also replaces missing or deficient clotting factors, thereby controlling or preventing bleeding.

Availability

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.

Contraindications

• Hypersensitivity to drug or to mouse, hamster, or bovine protein

Precautions

Use cautiously in:
• hepatic disease
• blood types A, B, and AB
• patients receiving factor VIII inhibitors
• pregnant patients
• neonates and infants.

Administration

• 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.

Route	Onset	Peak	Duration
I.V.	Immediate	1-2 hr	Unknown

Adverse reactions

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

Interactions

Drug-diagnostic tests. Bilirubin, creatine kinase: increased levels

Hemoglobin, platelets: decreased values

Patient monitoring

☞ 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).

Patient teaching

☞ 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.