Fibrinogen
Overview
Fibrinogen, also known as coagulation factor I, is a glycoprotein synthesized in the liver and plays a central role in the final stages of the blood coagulation cascade. It is converted by thrombin into fibrin, which forms a stable clot that helps stop bleeding. Therapeutic fibrinogen is available as a human plasma-derived concentrate used to restore deficient or depleted fibrinogen levels in patients with bleeding disorders. It is administered intravenously and is critical in both inherited and acquired conditions associated with hypofibrinogenemia or afibrinogenemia. In acute bleeding scenarios, fibrinogen is often the first coagulation factor to fall to critically low levels, making its replacement essential for achieving hemostasis. Its clinical importance extends to trauma, surgery, and obstetric hemorrhage, where rapid correction of fibrinogen levels can be life-saving.
Background and Date of Approval
Fibrinogen concentrate therapies have been developed from human plasma to provide targeted replacement therapy in patients with fibrinogen deficiency. One of the earliest widely used products, fibrinogen concentrate (human), received approval from the United States Food and Drug Administration on January 16, 2009 for the treatment of acute bleeding episodes in patients with congenital fibrinogen deficiency. Subsequent regulatory developments expanded the availability of fibrinogen products, including approvals for acquired fibrinogen deficiency and newer formulations. Expanded indications for acquired fibrinogen deficiency were granted in September 2024. More recently, fibrinogen (human-chmt) received approval from the United States Food and Drug Administration on December 16, 2025 for treatment of acute bleeding in congenital fibrinogen deficiency. These milestones reflect ongoing advancements in plasma-derived and recombinant coagulation therapies.
Uses
Fibrinogen is indicated for the treatment of acute bleeding episodes in patients with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia. It is also used for fibrinogen supplementation in acquired fibrinogen deficiency, which may occur during major trauma, surgery, or obstetric hemorrhage. The therapy is typically used as replacement treatment to restore adequate fibrinogen levels and may be used alone or as part of comprehensive hemostatic management.
Administration
Fibrinogen concentrate is administered intravenously following reconstitution. Dosing is individualized based on body weight, baseline fibrinogen levels, and severity of bleeding. The goal is to achieve and maintain target plasma fibrinogen levels sufficient for hemostasis. Repeat dosing may be required depending on ongoing bleeding and clinical response. Monitoring includes laboratory measurement of fibrinogen levels and assessment of bleeding control.
Side Effects
Common side effects include mild infusion-related reactions such as headache, fever, nausea, and chills. Some patients may experience local reactions or transient discomfort during administration. These effects are generally mild and manageable under medical supervision.
Warnings
Serious risks include thromboembolic events such as deep vein thrombosis or pulmonary embolism, particularly in patients with underlying risk factors. Hypersensitivity reactions, including anaphylaxis, may occur rarely. There is also a theoretical risk of viral transmission with plasma-derived products, although modern purification processes significantly reduce this risk. Treatment should be discontinued if severe reactions occur.
Precautions
Before initiating therapy, patients should be evaluated for fibrinogen levels and underlying causes of deficiency. Caution is required in patients with a history of thrombosis or disseminated intravascular coagulation. Concurrent use with other procoagulant agents may increase thrombotic risk and should be carefully monitored. As a biologic product, fibrinogen has minimal classical drug interactions but requires clinical vigilance in complex bleeding management.
Expert Tips
Fibrinogen replacement should be guided by both clinical assessment and laboratory monitoring. Early administration in severe bleeding improves outcomes. Proper reconstitution and timely infusion are essential for efficacy. Clinicians should target specific fibrinogen thresholds depending on the clinical scenario. Coordination with multidisciplinary teams, especially in trauma or surgical settings, is important for optimal patient care. Patient monitoring should focus on both bleeding control and signs of thrombosis.