Pharmacology · Class
Coagulation factor replacement and haemophilia agents !
Concentrates that replace a missing clotting factor (VIII in haemophilia A, IX in haemophilia B), plus emicizumab, which does factor VIII's job.
Updated 2026-11-01
What they are
Plasma-derived or recombinant factor concentrates are infused to prevent bleeds (prophylaxis) or to treat them. Some patients develop inhibitors, antibodies that neutralise the infused factor. Emicizumab, a bispecific antibody, is a non-factor option for haemophilia A given under the skin.
Mechanism of action
Factors VIII and IX form the intrinsic tenase complex on activated platelets, in which factor IXa, helped by factor VIIIa, activates factor X. Replacing the missing factor restores thrombin generation; emicizumab bridges factor IXa and factor X itself.
Target: Intrinsic tenase (factor IXa + VIIIa → factor X)
Drugs in this class
- Coagulation factor VIIIPlasma-derived or recombinant factor VIII infused to prevent and treat bleeding in haemophilia A.Factor VIII itself (cofactor of factor IXa in the tenase complex)
- Coagulation factor IXPlasma-derived or recombinant factor IX infused to prevent and treat bleeding in haemophilia B.Factor IX itself (the serine protease of the tenase complex)
- EmicizumabA bispecific antibody that bridges factors IXa and X, doing factor VIII's job. Given under the skin to prevent bleeds…Factor IXa and factor X (bridged by the antibody)
Others in the class
- recombinant factor VIIa
- prothrombin complex concentrate
- von Willebrand factor concentrate
Test yourself
Think of the answer, then tap the question to see it.
Which factor is missing in haemophilia B?
Factor IX.
What is an inhibitor in haemophilia?
An antibody that neutralises the infused factor.
Which test is prolonged in haemophilia?
The aPTT (the PT is normal).
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Farmacología básica y clínica (Katzung), 16.ª ed., cap. 34 (McGraw Hill, 2025); Treatment of Hemophilia | Hemophilia | CDC (Centers for Disease Control and Prevention, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 36 (McGraw Hill, 2023); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.