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Plasma-derived fibrinogen concentrate Pregnancy: No controlled clinical trials in human pregnancy; as the active substance is of human origin it is catabolised like the patient's own protein and is not expected to have adverse effects on reproduction or the foetus, and clinical experience in obstetric complications suggests no harmful effects are to be expected. Lactation: it is unknown whether it is excreted in human milk, and a risk to the suckling child cannot be excluded - weigh the benefit of breast-feeding against the benefit of therapy (UK SPC 4.6).

Fibrinogen (Specialist drug)

Brand names: RiaSTAP, Fibryga

Fibrinogen concentrate is a plasma-derived clotting factor (factor I) used to treat or prevent bleeding in congenital fibrinogen deficiency and in acquired hypofibrinogenaemia.

Adult dose

Dose: Fibrinogen substitution therapy for bleeding: if the patient's fibrinogen level is not known, the recommended initial dose is 70 mg/kg body weight intravenously. Where the fibrinogen level is known, the individual dose is calculated from the measured (functional) plasma fibrinogen level and the clinical condition rather than from a fixed figure
Route: Intravenous injection or infusion - the reconstituted solution should be warmed to room or body temperature before administration, then injected or infused slowly at a rate which the patient finds comfortable; the injection or infusion rate should not exceed approximately 5 ml per minute
Frequency: The amount and frequency of administration are determined on an individual patient basis by regular measurement of plasma fibrinogen level and continuous monitoring of the clinical condition. The target level of 1 g/l for minor events (e.g. epistaxis, intramuscular bleeding or menorrhagia) should be maintained for at least three days; the target level of 1.5 g/l for major events (e.g. head trauma or intracranial haemorrhage) should be maintained for seven days
Treatment should be initiated under the supervision of a physician experienced in the treatment of coagulation disorders. The dosage and duration of substitution therapy depend on the severity of the disorder, the location and extent of bleeding and the patient's clinical condition. Reference values quoted in the SPC: normal plasma fibrinogen level is in the range 1.5-4.5 g/l, and the critical plasma fibrinogen level below which haemorrhages may occur is approximately 0.5-1.0 g/l. In case of major surgical intervention, precise monitoring of replacement therapy by coagulation assays is essential. The 70 mg/kg figure is an INITIAL dose for the situation where the fibrinogen level is unknown - it is not a fixed regimen, and no repeat interval is specified. NO MAXIMUM DOSE is stated in the SPC, so none is published; the 5 ml/minute limit above is an administration RATE, not a dose ceiling, and must not be treated as one. The product contains up to 164 mg (7.1 mmol) sodium per vial, which corresponds to 11.5 mg (0.5 mmol) sodium per kg body weight when the recommended initial dose of 70 mg/kg is applied - relevant for patients on a controlled sodium diet. Some sections of the product information we used were incomplete — check the full SPC.

Paediatric dose

Dose: 70 mg/kg
Route: Intravenous injection or infusion, at a rate not exceeding approximately 5 ml per minute
Frequency: Individualised by regular measurement of plasma fibrinogen level and continuous monitoring of the clinical condition, to the same target levels as adults (1 g/l maintained for at least three days for minor events; 1.5 g/l maintained for seven days for major events)
This is the label's own paediatric statement, not a scaled adult figure: 'Limited data from clinical studies regarding the dosage of Riastap in children are available. Resulting from these studies, as well as from long lasting clinical experience with fibrinogen products, dosage recommendations in the treatment of children are the same as for adults.' Section 4.4 flags neonates among the groups in whom the potential benefit should be weighed against the risk of thromboembolic complications, with caution and close monitoring. The reconstitution volume is not given in the retrieved sections, so no concentration is stored and no volume can be calculated here - obtain it from section 6.6 of the full SPC. Verify paediatric use against a children's formulary.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

This is the label's own paediatric statement, not a scaled adult figure: 'Limited data from clinical studies regarding the dosage of Riastap in children are available. Resulting from these studies, as well as from long lasting clinical experience with fibrinogen products, dosage recommendations in the treatment of children are the same as for adults.' Section 4.4 flags neonates among the groups in whom the potential benefit should be weighed against the risk of thromboembolic complications, with caution and close monitoring. The reconstitution volume is not given in the retrieved sections, so no concentration is stored and no volume can be calculated here - obtain it from section 6.6 of the full SPC. Verify paediatric use against a children's formulary.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients

Side effects

  • Pyrexia (very common)
  • Thromboembolic events (common) - isolated cases have been fatal
  • Anaphylactic reactions including anaphylactic shock (uncommon)
  • Allergic reactions including generalised urticaria, rash, dyspnoea, tachycardia, nausea, vomiting, chills, pyrexia, chest pain, cough and decreased blood pressure (frequency unknown)
  • Theoretical risk of transmission of infective agents, as with any medicinal product prepared from human blood or plasma

Monitoring

  • Determine the (functional) fibrinogen level to calculate the individual dosage, and measure plasma fibrinogen regularly thereafter alongside continuous monitoring of the clinical condition and other replacement therapies used
  • Precise monitoring of replacement therapy by coagulation assays is essential in major surgical intervention
  • Observe patients closely for signs or symptoms of thrombosis - the risk is increased particularly with high dose or repeated dosing
  • Weigh benefit against thromboembolic risk, with caution and close monitoring, in patients with a history of coronary heart disease or myocardial infarction, liver disease, peri- or post-operative patients, neonates, and patients at risk of thromboembolic events or disseminated intravascular coagulation
  • Stop the injection/infusion immediately if allergic or anaphylactic-type reactions occur, and implement standard treatment for shock in case of anaphylactic shock
  • Record the name and batch number of the product every time it is administered, to maintain the link between patient and batch
  • Consider hepatitis A and hepatitis B vaccination for patients in regular or repeated receipt of human plasma-derived products

Clinical monograph

How it works

It replaces deficient fibrinogen, the precursor that is converted by thrombin to fibrin to form a stable blood clot and support haemostasis.

Prescribing in practice

  • There is a risk of thromboembolism with fibrinogen replacement, so it should be used at the lowest effective level guided by the clinical situation and laboratory results.
  • As a plasma-derived product, hypersensitivity reactions can occur and patients should be observed during administration.
  • Use should be directed by a haematologist or specialist and guided by fibrinogen levels.

Monitoring

Monitor plasma fibrinogen levels and clinical bleeding to guide dosing, and observe for signs of thrombosis.

Counselling the patient

  • Report any signs of a clot such as leg swelling, chest pain or breathlessness.
  • Tell the team about any reaction during the infusion.
  • This is a specialist treatment given and supervised by your haematology team.

Evidence & guidelines

Fibrinogen concentrate is established replacement therapy for fibrinogen deficiency and acquired hypofibrinogenaemia, with use guided by specialist haematology practice.

Reference: UKHCDO; major-haemorrhage protocols; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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