Fibclot: Uses, Dosage & Side Effects
A plasma-derived human fibrinogen concentrate for the treatment and prevention of bleeding in patients with congenital fibrinogen deficiency
Fibclot is a plasma-derived human fibrinogen (coagulation factor I) concentrate indicated for the treatment and prophylaxis of bleeding episodes in patients with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia. Fibrinogen is a critical coagulation protein that serves as the precursor to fibrin, the structural foundation of blood clots. In patients who lack sufficient fibrinogen, even minor injuries can lead to prolonged or life-threatening bleeding. Fibclot is administered intravenously in a hospital or clinical setting and provides an immediate, measurable increase in plasma fibrinogen levels, restoring the capacity for normal hemostasis. It undergoes rigorous viral inactivation during manufacturing to minimize the risk of transmitting infectious agents.
Quick Facts: Fibclot
Key Takeaways
- Fibclot is a purified, virus-inactivated human fibrinogen concentrate specifically designed for patients with congenital fibrinogen deficiency (afibrinogenemia or hypofibrinogenemia) who experience bleeding or require surgical prophylaxis.
- It is administered intravenously by healthcare professionals, with dosing individualized based on body weight, baseline fibrinogen levels, target plasma level, and clinical situation (typically 70 mg/kg as an initial dose for acute bleeding).
- Fibclot provides an immediate and quantifiable increase in plasma fibrinogen concentration, with a biological half-life of approximately 3–4 days, allowing for predictable dosing intervals.
- The most clinically significant risk is thromboembolic complications, particularly with high or repeated doses; patients should be monitored for signs of deep vein thrombosis, pulmonary embolism, or arterial thrombosis during treatment.
- As a plasma-derived product, Fibclot undergoes multiple viral inactivation and removal steps during manufacturing, but a theoretical residual risk of transmitting known or unknown infectious agents cannot be entirely eliminated.
What Is Fibclot and What Is It Used For?
Fibclot contains human fibrinogen, also known as coagulation factor I, which is one of the most critical proteins in the blood coagulation cascade. Fibrinogen is a large glycoprotein (molecular weight approximately 340 kDa) produced primarily by the liver and circulating in the bloodstream at concentrations of 1.5–4.0 g/L in healthy individuals. It is the substrate upon which the entire coagulation process ultimately converges: when activated by thrombin (the final enzyme in the coagulation cascade), fibrinogen is cleaved into fibrin monomers, which then polymerize spontaneously and are stabilized by cross-linking through activated factor XIII (factor XIIIa), forming the insoluble fibrin mesh that constitutes the structural backbone of a blood clot.
Without adequate circulating fibrinogen, this essential final step of coagulation cannot occur. Patients with congenital fibrinogen deficiency have an inherited genetic defect in one of the three genes (FGA, FGB, or FGG) encoding the alpha, beta, and gamma chains of the fibrinogen molecule, respectively. These mutations can result in a complete absence of fibrinogen production (afibrinogenemia, with plasma fibrinogen levels below 0.1 g/L), significantly reduced production (hypofibrinogenemia, with levels typically between 0.1 and 1.5 g/L), or production of a dysfunctional fibrinogen molecule (dysfibrinogenemia). Afibrinogenemia and severe hypofibrinogenemia are rare conditions, with an estimated prevalence of approximately 1 in 1,000,000 for afibrinogenemia and somewhat higher for hypofibrinogenemia, though mild forms may be underdiagnosed.
Patients with afibrinogenemia may experience a broad spectrum of bleeding manifestations throughout their lives. Umbilical cord bleeding is often the first clinical sign, occurring in up to 85% of patients with afibrinogenemia shortly after birth. Other common bleeding events include spontaneous or trauma-related bleeding from mucosal surfaces (epistaxis, gingival bleeding, gastrointestinal hemorrhage), hemarthrosis (bleeding into joints similar to hemophilia), muscle hematomas, menorrhagia (heavy menstrual bleeding) in women, and potentially life-threatening intracranial hemorrhage. Patients with hypofibrinogenemia tend to have milder bleeding manifestations that correlate roughly with their circulating fibrinogen levels, but they can still experience significant bleeding during surgery, trauma, or other hemostatic challenges.
Fibclot is manufactured from pooled human plasma collected from carefully screened voluntary donors. The manufacturing process involves purification of fibrinogen from plasma using precipitation and chromatographic techniques, followed by dedicated viral inactivation and removal steps. These steps are designed to minimize the risk of transmitting known and emerging blood-borne viruses and other pathogens. The final product is a lyophilized (freeze-dried) powder that is reconstituted with the supplied solvent immediately before administration. Each vial of Fibclot contains 1.5 g of human fibrinogen, providing a standardized and predictable dose that enables precise management of fibrinogen levels in patients with congenital deficiency.
Fibclot is indicated for the treatment of acute bleeding episodes and for prophylaxis of bleeding in patients with congenital fibrinogen deficiency who are undergoing surgery or other invasive procedures. It may also be used for routine long-term prophylaxis in patients with severe afibrinogenemia who experience frequent spontaneous bleeding episodes. The goal of treatment is to raise and maintain plasma fibrinogen levels above a minimum threshold that depends on the clinical context: typically above 1.0 g/L for minor bleeding or procedures, and above 1.5–2.0 g/L for major surgery, significant trauma, or life-threatening hemorrhage such as intracranial bleeding.
Fibclot offers several important advantages compared with cryoprecipitate, the traditional plasma component used to replace fibrinogen: (1) standardized fibrinogen content per vial enabling precise dosing, (2) dedicated viral inactivation processing for enhanced safety, (3) room temperature storage and longer shelf life, (4) smaller infusion volume reducing fluid overload risk, and (5) no requirement for ABO blood group matching. International guidelines from the ISTH, BSH, and WFH increasingly recommend purified fibrinogen concentrates over cryoprecipitate for the management of congenital fibrinogen deficiency.
What Should You Know Before Taking Fibclot?
Contraindications
The only absolute contraindication to the use of Fibclot is known hypersensitivity (allergy) to the active substance (human fibrinogen) or to any of the excipients in the formulation. Excipients in Fibclot include sodium chloride, sodium citrate, arginine hydrochloride, lysine hydrochloride, and water for injections (as solvent). Although allergic reactions to plasma-derived fibrinogen concentrates are uncommon, they can range from mild hypersensitivity symptoms such as urticaria (hives) and pruritus (itching) to severe anaphylactic or anaphylactoid reactions with hypotension, bronchospasm, and cardiovascular collapse. If any signs of a severe allergic reaction develop during infusion, the administration must be stopped immediately and appropriate emergency treatment initiated.
Fibclot should be used with great caution in patients with a known history of thromboembolic disease, disseminated intravascular coagulation (DIC), or known thrombophilic conditions (such as factor V Leiden mutation, prothrombin gene mutation, or antithrombin deficiency), as fibrinogen replacement in these contexts could theoretically increase the risk of pathological clot formation. However, even in these patients, the potential benefits of controlling life-threatening hemorrhage typically outweigh the thrombotic risks, and treatment decisions should be made on an individual basis by an experienced hematologist.
Warnings and Precautions
There is a risk of thromboembolic complications (blood clots in veins or arteries) when using Fibclot, especially with high doses, repeated infusions, or in patients with additional risk factors for thrombosis. Patients should be monitored for signs and symptoms of deep vein thrombosis, pulmonary embolism, myocardial infarction, or stroke during and after treatment. The dose should be the minimum necessary to achieve and maintain adequate hemostasis.
Several important warnings and precautions should be considered before and during treatment with Fibclot:
- Thrombotic risk: Fibrinogen replacement can increase the risk of thromboembolic events, particularly when high plasma levels are maintained over prolonged periods, in patients with pre-existing cardiovascular risk factors, in patients who are immobilized, or in those with a history of venous thromboembolism. Plasma fibrinogen levels should be monitored regularly during treatment, and the dose should be adjusted to maintain the lowest effective level. There have been post-marketing reports of both venous and arterial thromboembolic events in patients receiving fibrinogen concentrate.
- Infectious agent transmission: Because Fibclot is manufactured from human plasma, it carries a theoretical risk of transmitting infectious agents, including viruses (known and unknown), prions, and other pathogens. The manufacturing process includes several dedicated viral inactivation and removal steps (including solvent/detergent treatment and nanofiltration) that are highly effective against enveloped viruses such as HIV, hepatitis B, and hepatitis C, and provide some protection against non-enveloped viruses. However, these measures may not be fully effective against all potential pathogens, particularly non-enveloped viruses (such as parvovirus B19 and hepatitis A) and novel or unknown agents. Patients receiving Fibclot should be informed of this residual risk and may be offered vaccination against hepatitis A and hepatitis B if not already immune.
- Inhibitory antibodies: In rare instances, patients with afibrinogenemia who receive fibrinogen replacement therapy may develop antibodies (inhibitors) against human fibrinogen. These antibodies can neutralize the therapeutic effect of the replacement product and may also trigger severe allergic or anaphylactic reactions. If the expected rise in fibrinogen levels is not achieved after infusion, or if bleeding is not controlled despite adequate dosing, the presence of inhibitory antibodies should be investigated through appropriate laboratory testing.
- Monitoring requirements: Plasma fibrinogen levels should be measured before the first infusion and monitored regularly during treatment to guide dosing. Standard coagulation tests (prothrombin time, activated partial thromboplastin time, thrombin time) and fibrinogen activity assays (Clauss method) should be used. In patients receiving long-term prophylaxis, trough fibrinogen levels should be maintained above an agreed minimum (typically 0.5–1.0 g/L) to prevent spontaneous bleeding.
Pregnancy and Breastfeeding
Congenital fibrinogen deficiency poses significant risks during pregnancy and childbirth. Women with afibrinogenemia or severe hypofibrinogenemia are at markedly increased risk of first-trimester miscarriage (reported in up to 50% of untreated pregnancies), placental abruption, antepartum hemorrhage, and severe postpartum hemorrhage. Fibrinogen replacement therapy during pregnancy is often essential for both maternal and fetal safety, and Fibclot may be used when clinically indicated under the supervision of a specialist hematologist and high-risk obstetrician.
Current guidelines recommend maintaining fibrinogen levels above 1.0 g/L throughout pregnancy, with higher targets (above 1.5–2.0 g/L) around the time of delivery and in the immediate postpartum period. The frequency of infusions and dosing should be guided by regular monitoring of plasma fibrinogen levels, which may need to be checked weekly during the third trimester and more frequently around delivery. It is not known whether Fibclot passes into breast milk, but human fibrinogen is a normal component of blood and is not expected to pose a risk to the breastfed infant.
Children and Elderly Patients
Fibclot can be used in pediatric patients of all ages, including neonates, as congenital fibrinogen deficiency may present at or shortly after birth (most commonly with umbilical cord stump bleeding). Dosing in children is based on body weight, using the same weight-based calculations as for adults. Clinical experience with Fibclot in neonates and infants is limited, but the pharmacokinetic properties of fibrinogen are not expected to differ fundamentally in younger patients, although the volume of distribution may be relatively larger. In elderly patients, dosing follows the same principles as in younger adults. However, elderly patients may have additional risk factors for thrombosis (e.g., reduced mobility, concomitant cardiovascular disease) and should be monitored with particular care for thromboembolic complications.
How Does Fibclot Interact with Other Drugs?
As a replacement therapy providing a physiological protein that is normally present in human blood, Fibclot does not interact with other drugs through conventional pharmacokinetic mechanisms such as cytochrome P450 enzyme inhibition or induction, protein binding displacement, or renal transporter competition. Human fibrinogen is metabolized through normal endogenous catabolic pathways and is consumed during clot formation and fibrinolysis. Therefore, traditional drug-drug interactions as seen with small molecule pharmaceuticals are not expected.
However, there are several important pharmacodynamic interactions that clinicians should be aware of when prescribing Fibclot:
| Drug / Drug Class | Interaction Type | Clinical Significance |
|---|---|---|
| Tranexamic acid | Increased thrombotic risk | Antifibrinolytic drugs prevent clot breakdown; combined with fibrinogen replacement, this may significantly increase the risk of thrombosis. Use with caution; dose reduction or enhanced monitoring may be needed. |
| Aminocaproic acid | Increased thrombotic risk | Same mechanism as tranexamic acid. Concurrent use increases the risk of thromboembolic events. Avoid unless the clinical benefit clearly outweighs the risk. |
| Factor XIII concentrate | Additive hemostatic effect | Factor XIII cross-links fibrin; co-administration may enhance clot stability. Can be used together when both deficiencies coexist but requires careful monitoring. |
| Prothrombin complex concentrates (PCCs) | Additive prothrombotic effect | PCCs provide additional coagulation factors; combined use may increase thrombotic risk. Use only when clearly indicated; monitor for thromboembolic events. |
| Heparins / Anticoagulants | Opposing effects | Anticoagulants may reduce the hemostatic efficacy of Fibclot. If both are needed (e.g., post-thrombotic prophylaxis), close monitoring of coagulation parameters is essential. |
| Recombinant factor VIIa (rFVIIa) | Additive prothrombotic effect | rFVIIa enhances thrombin generation; combined use with fibrinogen concentrate increases thrombotic potential. Use only in life-threatening hemorrhage unresponsive to standard therapy. |
In clinical practice, the most important interaction to be aware of is the combination of Fibclot with antifibrinolytic agents such as tranexamic acid or aminocaproic acid. While antifibrinolytics are frequently used in the management of bleeding in patients with coagulation disorders (for example, to control mucosal bleeding, menorrhagia, or bleeding during dental procedures), their concurrent use with fibrinogen replacement increases the net prothrombotic state by both providing the substrate for clot formation (fibrinogen) and preventing the body’s natural mechanism for dissolving those clots (fibrinolysis). This combination should only be used when clearly indicated, at the lowest effective doses of both agents, and with enhanced clinical vigilance for signs of thrombosis.
Fibclot can be administered alongside other coagulation factor concentrates (such as factor VIII or factor IX concentrates) when patients have combined coagulation deficiencies or when treating complex bleeding situations. However, it should not be mixed with other medicinal products in the same syringe or infusion line. If multiple products need to be given, they should be administered through separate access points or the line should be flushed with normal saline between products.
What Is the Correct Dosage of Fibclot?
The dosing of Fibclot must always be individualized based on several factors: the patient’s body weight, the current (baseline) plasma fibrinogen level, the desired target plasma fibrinogen level (which varies depending on the clinical situation), and the patient’s clinical response. The general dosing principle is that 1 mg of fibrinogen per kilogram of body weight will increase the plasma fibrinogen level by approximately 0.017 g/L (1.7 mg/dL). This pharmacokinetic relationship allows clinicians to calculate the dose required to raise the fibrinogen level from its current value to the target value.
The general dosing formula is:
Dose (mg/kg) = (Target fibrinogen level – Measured fibrinogen level) ÷ 0.017
For example, for a patient with afibrinogenemia (baseline 0 g/L) requiring a target of 1.0 g/L: Dose = (1.0 – 0) ÷ 0.017 = approximately 59 mg/kg. In practice, an initial dose of 70 mg/kg is commonly recommended to account for individual variability.
Adults
| Clinical Situation | Target Fibrinogen Level | Typical Initial Dose | Duration / Frequency |
|---|---|---|---|
| Minor bleeding (e.g., epistaxis, gingival, soft tissue) | ≥1.0 g/L | 50–70 mg/kg | Single dose; repeat if bleeding persists based on levels |
| Major bleeding (e.g., GI hemorrhage, hemarthrosis, severe trauma) | ≥1.5 g/L | 70 mg/kg | Repeat every 2–3 days to maintain target; adjust by lab monitoring |
| Life-threatening bleeding (e.g., intracranial hemorrhage) | ≥2.0 g/L | 70–100 mg/kg | Repeat every 1–2 days; intensive monitoring for 7–14 days |
| Minor surgery (e.g., dental extraction, skin biopsy) | ≥1.0 g/L | 50–70 mg/kg pre-operatively | Maintain for 1–3 days post-operatively |
| Major surgery (e.g., abdominal, orthopedic) | ≥1.5–2.0 g/L | 70 mg/kg pre-operatively | Repeat every 2–3 days; maintain levels for 7–14 days or until wound healing |
| Long-term prophylaxis | Trough ≥0.5–1.0 g/L | 40–70 mg/kg | Every 7–14 days; individualized to maintain trough levels |
Children
Dosing in children, including neonates and infants, follows the same weight-based approach as in adults. The dose is calculated using the same formula: Dose (mg/kg) = (Target fibrinogen level – Measured fibrinogen level) ÷ 0.017. There are no specific dosing adjustments for age in pediatric patients. However, the volume of distribution for fibrinogen may be slightly larger in neonates and young infants, which means they may require slightly higher weight-based doses to achieve the same plasma level increase. Clinicians should rely on measured post-infusion fibrinogen levels to guide subsequent dosing rather than relying solely on calculated predictions.
For neonates presenting with umbilical stump bleeding (the most common presentation of afibrinogenemia), an initial dose of 70 mg/kg is recommended, with careful monitoring and repeat dosing as needed. Children undergoing surgical procedures should be dosed according to the same target levels as adults.
Elderly
No specific dose adjustment is required for elderly patients. The same weight-based dosing principles apply. However, elderly patients should be monitored with particular care for thromboembolic complications, as they may have additional age-related risk factors for thrombosis including reduced mobility, cardiovascular comorbidities, and concurrent use of other prothrombotic medications. The target fibrinogen level should be set at the minimum effective level to reduce thrombotic risk.
Administration
Fibclot is supplied as a lyophilized powder in a vial, together with the solvent (water for injections) needed for reconstitution. Reconstitution should be performed aseptically using the provided transfer device. The powder should be dissolved gently by swirling (not shaking, to avoid foaming and protein denaturation) until a clear or slightly opalescent solution is obtained. The reconstituted solution should be inspected visually for particulate matter and discoloration before administration; turbid solutions or those containing visible particles must not be used.
The reconstituted solution is administered by slow intravenous injection or infusion. The recommended maximum infusion rate is 4 mL per minute. Rapid infusion should be avoided, as it may be associated with vasomotor reactions. The reconstituted product should be used promptly after preparation; chemical and physical in-use stability has been demonstrated for up to 24 hours at room temperature, but from a microbiological standpoint, immediate use is recommended.
Missed Dose
In patients receiving scheduled prophylactic infusions, a missed dose should be administered as soon as possible. If the next scheduled dose is imminent, the missed dose can be omitted and the regular schedule resumed. A plasma fibrinogen level should be checked before the next dose to assess whether an additional dose is needed. Patients and caregivers should be educated about the importance of adhering to the prophylactic schedule, as missed doses can result in subtherapeutic fibrinogen levels and an increased risk of spontaneous bleeding.
Overdose
Cases of overdose with fibrinogen concentrate have not been systematically documented, but excessive dosing would be expected to result in supraphysiological plasma fibrinogen levels and an increased risk of thromboembolic complications. If overdose is suspected, plasma fibrinogen levels should be measured immediately, and the patient should be closely monitored for signs of venous or arterial thrombosis (deep vein thrombosis, pulmonary embolism, stroke, or myocardial infarction). In the event of confirmed thromboembolism, standard antithrombotic treatment should be initiated in accordance with current guidelines, with the understanding that anticoagulation must be carefully balanced against the underlying bleeding tendency in these patients.
What Are the Side Effects of Fibclot?
Like all plasma-derived medicinal products, Fibclot can cause side effects, although not everyone who receives it will experience them. The overall safety profile of fibrinogen concentrates has been established through clinical trials, post-marketing surveillance, and decades of clinical use in patients with congenital fibrinogen deficiency. The following side effects have been reported in association with Fibclot and other human fibrinogen concentrates:
Common
- Headache
- Fever (pyrexia)
- Allergic skin reactions (urticaria, rash, pruritus)
- Nausea
Uncommon
- Thromboembolic events (deep vein thrombosis, pulmonary embolism)
- Arterial thrombotic events (myocardial infarction, stroke)
- Infusion site reactions (pain, erythema, swelling)
- Chills and rigors
- Flushing
- Dyspnea (shortness of breath)
Rare
- Severe anaphylactic or anaphylactoid reactions
- Development of inhibitory antibodies against fibrinogen
- Disseminated intravascular coagulation (DIC)
- Tachycardia (rapid heart rate)
- Hypotension (low blood pressure)
Very Rare / Theoretical
- Transmission of infectious agents (despite viral inactivation measures)
- Parvovirus B19 infection (particularly relevant for seronegative patients)
- Hepatitis A transmission
The most important safety concern with Fibclot is the risk of thromboembolic events. This risk is inherent to all fibrinogen replacement therapies and is related to the restoration of plasma fibrinogen levels that enable clot formation. Thromboembolic events are more likely to occur when plasma fibrinogen levels are raised above normal physiological ranges, when treatment is prolonged, in patients with additional prothrombotic risk factors (immobilization, obesity, smoking, oral contraceptive use, malignancy, indwelling venous catheters), and when fibrinogen is used concurrently with antifibrinolytic agents. Patients should be educated about the signs and symptoms of thromboembolism (leg pain or swelling, unexplained shortness of breath, chest pain, sudden neurological symptoms) and should seek immediate medical attention if these occur.
Allergic and hypersensitivity reactions can occur during or shortly after infusion. These range in severity from mild cutaneous reactions (rash, hives, itching) to severe systemic reactions (anaphylaxis with hypotension, bronchospasm, and circulatory collapse). If a hypersensitivity reaction occurs, the infusion should be stopped immediately and appropriate treatment administered, including epinephrine (adrenaline) for anaphylaxis. Patients who develop allergic reactions should be evaluated for the presence of anti-fibrinogen antibodies before further treatment.
The risk of infectious agent transmission is a general concern with all plasma-derived products. The manufacturing process for Fibclot includes multiple dedicated viral inactivation and removal steps that are highly effective against enveloped viruses (HIV, hepatitis B, hepatitis C). However, these steps may be less effective against non-enveloped viruses (parvovirus B19, hepatitis A) and against currently unknown pathogens. Patients should be made aware of this residual risk and may benefit from vaccination against hepatitis A and B. Parvovirus B19 infection may be particularly concerning in pregnant women (risk of fetal hydrops) and in immunocompromised patients.
Contact your healthcare provider or seek emergency medical care immediately if you experience: signs of a blood clot (sudden leg pain or swelling, unexplained shortness of breath, chest pain, sudden confusion or vision problems), signs of a severe allergic reaction (difficulty breathing, swelling of face or throat, severe skin rash, dizziness or collapse), or unexplained fever or jaundice after treatment.
How Should You Store Fibclot?
Proper storage of Fibclot is essential to maintain the integrity and efficacy of the fibrinogen protein. As a lyophilized (freeze-dried) product, Fibclot has favorable storage characteristics compared with some other blood products. The unopened product should be stored at or below 25°C (77°F) in the original packaging to protect the contents from light. Unlike cryoprecipitate (which requires storage at –25°C or below), Fibclot can be stored at room temperature, which is a significant practical advantage in terms of availability, emergency access, and logistics.
Do not freeze Fibclot, as freezing and thawing can damage the protein structure and reduce the efficacy of the product. Keep the product in its outer carton until ready for use, as the lyophilized powder is sensitive to light exposure over time. Always check the expiry date printed on the vial and outer packaging before reconstitution; expired product should not be used and should be returned to the pharmacy for disposal.
Once reconstituted with the supplied solvent, Fibclot should ideally be used immediately. Chemical and physical stability of the reconstituted solution has been demonstrated for up to 24 hours at room temperature (not exceeding 25°C). However, from a microbiological perspective, since the product does not contain preservatives, immediate use is recommended to minimize the risk of microbial contamination. If the reconstituted solution is not used immediately, any remaining solution should be discarded. Do not refrigerate or re-freeze the reconstituted solution.
The product should be kept out of the reach and sight of children. Do not use Fibclot if the reconstituted solution is cloudy, contains particles, or shows any signs of deterioration. Unused product or waste material should be disposed of in accordance with local requirements for pharmaceutical waste and blood products.
What Does Fibclot Contain?
Fibclot is a carefully formulated pharmaceutical product containing purified human fibrinogen as its sole active ingredient. Understanding its composition is important for healthcare providers, particularly when assessing patients for potential allergic reactions or when managing patients with specific dietary or medical restrictions.
Active Ingredient
The active substance is human fibrinogen (coagulation factor I), derived from pooled human plasma collected from voluntary, carefully screened blood donors. Each vial contains 1.5 g of fibrinogen. When reconstituted with 100 mL of the supplied solvent (water for injections), the resulting solution has a fibrinogen concentration of approximately 15 mg/mL. The fibrinogen in Fibclot consists of the complete hexameric molecule (two sets of three polypeptide chains: A-alpha, B-beta, and gamma), preserving its full physiological capacity to be converted to fibrin by thrombin and to be cross-linked by factor XIIIa.
Excipients
- Sodium chloride: Used as a tonicity agent to ensure the reconstituted solution is isotonic with blood.
- Sodium citrate: Acts as a stabilizer and buffering agent to maintain the appropriate pH for protein stability.
- Arginine hydrochloride: Used as a stabilizer to maintain fibrinogen in its native conformation during lyophilization and storage, preventing aggregation and denaturation.
- Lysine hydrochloride: An additional amino acid stabilizer that helps preserve the structural integrity and biological activity of the fibrinogen molecule.
The solvent supplied with Fibclot is water for injections (100 mL), which meets pharmacopoeial specifications for sterility and endotoxin levels. The reconstituted solution should be clear to slightly opalescent and colorless to pale yellow. Any solution that appears turbid, deeply colored, or contains visible particulate matter should not be administered.
Fibclot contains sodium. When fully reconstituted, the sodium content should be taken into account in patients on a controlled sodium diet, particularly when multiple vials are administered. The exact sodium content per vial is specified in the product literature provided with each batch. Fibclot does not contain preservatives, latex (in the packaging), or any animal-derived excipients other than the human plasma-derived active ingredient.
Frequently Asked Questions About Fibclot
Fibclot is a plasma-derived human fibrinogen concentrate used for the treatment and prophylaxis of bleeding in patients with congenital fibrinogen deficiency, including afibrinogenemia (complete absence of fibrinogen) and hypofibrinogenemia (abnormally low fibrinogen levels). It is administered intravenously by healthcare professionals to restore normal clot-forming ability.
Fibclot is given as a slow intravenous injection or infusion. The powder must be reconstituted with the provided solvent before use. The typical initial dose is 70 mg per kilogram of body weight, adjusted based on the type and severity of bleeding, the patient’s plasma fibrinogen level, and clinical response. It should only be administered under the supervision of a healthcare professional experienced in treating coagulation disorders.
The most significant risk associated with Fibclot is thromboembolic events (blood clots), which can occur especially with high doses, prolonged treatment, or in patients with additional risk factors for thrombosis. Allergic reactions are possible, ranging from mild skin reactions to rare severe anaphylaxis. As a plasma-derived product, there is also a very low theoretical risk of transmission of infectious agents despite extensive viral inactivation measures.
Yes, Fibclot may be used during pregnancy when clinically indicated. Women with congenital fibrinogen deficiency are at increased risk of obstetric complications including miscarriage, placental abruption, and postpartum hemorrhage. Fibrinogen replacement therapy during pregnancy and delivery is often essential for both maternal and fetal safety. Treatment should be managed by a specialist hematologist in collaboration with a high-risk obstetrician.
Fibclot is a purified, virus-inactivated fibrinogen concentrate with a standardized dose per vial, while cryoprecipitate is a blood component prepared from fresh frozen plasma that contains variable amounts of fibrinogen along with other clotting factors. Fibclot offers several advantages: precise dosing, dedicated viral inactivation processing, room temperature storage, smaller infusion volume, and no requirement for ABO blood group matching. International guidelines increasingly recommend fibrinogen concentrates like Fibclot over cryoprecipitate for treating congenital fibrinogen deficiency.
Fibclot should be stored at or below 25°C in its original packaging to protect from light. Do not freeze. Once reconstituted, the solution should be used immediately, though physical and chemical stability has been demonstrated for up to 24 hours at room temperature. Any unused reconstituted solution should be discarded. Always check the expiry date before use.
References
- European Medicines Agency (EMA). Fibclot – Summary of Product Characteristics. Available from: www.ema.europa.eu. Accessed January 2026.
- Casini A, de Moerloose P, Neerman-Arbez M. Clinical Features and Management of Congenital Fibrinogen Deficiencies. Semin Thromb Hemost. 2016;42(4):366-374. doi:10.1055/s-0036-1571339
- Mumford AD, Ackroyd S, Alikhan R, et al. Guideline for diagnosis and management of the rare coagulation disorders: a United Kingdom Haemophilia Centre Doctors’ Organisation guideline on behalf of the British Committee for Standards in Haematology. Br J Haematol. 2014;167(3):304-326. doi:10.1111/bjh.13058
- World Federation of Hemophilia (WFH). Guidelines for the Management of Hemophilia and Rare Bleeding Disorders. 3rd ed. Montreal: WFH; 2024. Available from: www.wfh.org.
- Casini A, Undas A, Palla R, Thachil J, de Moerloose P; Subcommittee on Factor XIII and Fibrinogen. Diagnosis and classification of congenital fibrinogen disorders: communication from the SSC of the ISTH. J Thromb Haemost. 2018;16(8):1536-1542. doi:10.1111/jth.14134
- Bornikova L, Peyvandi F, Allen G, Bernstein J, Manco-Johnson MJ. Fibrinogen replacement therapy for congenital fibrinogen deficiency. J Thromb Haemost. 2011;9(9):1687-1704. doi:10.1111/j.1538-7836.2011.04424.x
- Peyvandi F, Palla R, Menegatti M, et al. Coagulation factor activity and clinical bleeding severity in rare bleeding disorders: results from the European Network of Rare Bleeding Disorders. J Thromb Haemost. 2012;10(4):615-621. doi:10.1111/j.1538-7836.2012.04653.x
- World Health Organization (WHO). Model List of Essential Medicines. 23rd List (2023). Geneva: WHO; 2023.
- Levy JH, Goodnough LT. How I use fibrinogen replacement therapy in acquired bleeding. Blood. 2015;125(9):1387-1393. doi:10.1182/blood-2014-08-552000
- International Society on Thrombosis and Haemostasis (ISTH). Guidelines on Fibrinogen Assays and Fibrinogen Replacement. J Thromb Haemost. 2024. doi:10.1111/jth.15896
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