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Coagulation Factor Replacement — Hypofibrinogenaemia Pregnancy: §4.6: animal reproduction studies have not been conducted with Riastap. Since the active substance is of human origin it is catabolised in the same manner as the patient's own protein, and these physiological constituents of human blood are not expected to induce adverse effects on reproduction or on the foetus. The safety of Riastap in human pregnancy has not been established in controlled clinical trials; clinical experience with fibrinogen concentrate in the treatment of obstetric complications suggests that no harmful effects on the course of the pregnancy or the health of the foetus or neonate are to be expected. Lactation: it is unknown whether Riastap is excreted in human milk and its use in lactating women has not been investigated; a risk to the suckling child cannot be excluded, so a decision must be made whether to discontinue breast-feeding or to discontinue/abstain from therapy. Fertility: no data available.

Fibrinogen Concentrate

Brand names: Riastap, Fibryga

Fibrinogen concentrate is a purified, plasma-derived clotting factor (factor I) preparation given intravenously to treat bleeding in congenital fibrinogen deficiency and acquired hypofibrinogenaemia.

Adult dose

Dose: CONGENITAL HYPO- OR AFIBRINOGENAEMIA, TREATMENT OF BLEEDING — the licensed indication of the sourced product (§4.1 verbatim: 'Treatment of bleeding in patients with congenital hypo-, or afibrinogenaemia with bleeding tendency'). INITIAL DOSE — §4.2 verbatim: 'If the patient's fibrinogen level is not known, the recommended dose is 70 mg per kg of body weight (bw) administered intravenously.' Where the fibrinogen level IS known, §4.2 requires the individual dose to be calculated from it instead: 'The (functional) fibrinogen level should be determined in order to calculate individual dosage and the amount and frequency of administration should be determined on an individual patient basis by regular measurement of plasma fibrinogen level and continuous monitoring of the clinical condition of the patient and other replacement therapies used.' SUBSEQUENT DOSES are titrated to target level — §4.2 verbatim: 'The target level (1 g/l) for minor events (e.g. epistaxis, intramuscular bleeding or menorrhagia) should be maintained for at least three days. The target level (1.5 g/l) for major events (e.g. head trauma or intracranial haemorrhage) should be maintained for seven days.' SCOPE — READ THIS BEFORE USING THE FIGURE: this covers CONGENITAL fibrinogen deficiency only. ACQUIRED hypofibrinogenaemia (major haemorrhage, post-partum haemorrhage, DIC, liver failure) is not an indication of this product and NO acquired-deficiency dose, target or formula is published here.
Route: Intravenous infusion or injection, after reconstitution. §4.2 verbatim: 'Intravenous infusion or injection. Riastap should be reconstituted according to section 6.6. 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: Individualised — §4.2: 'the amount and frequency of administration should be determined on an individual patient basis by regular measurement of plasma fibrinogen level and continuous monitoring of the clinical condition of the patient and other replacement therapies used.' Duration is set by the target level: at least three days for minor events, seven days for major events. Treatment should be initiated under the supervision of a physician experienced in the treatment of coagulation disorders.
Max: No maximum dose is stated in this SPC. 70 mg/kg is the recommended INITIAL dose for the case where the patient's fibrinogen level is not known — not a ceiling; subsequent dosing is titrated to the measured plasma fibrinogen level and to the target levels above (1 g/l maintained for at least three days after minor events, 1.5 g/l for seven days after major events).
That hold was recorded because §4.1 had never been fetched, so the licensed indication could not be checked and the draft could not tell whether the page's acquired-deficiency use was covered. §4.1 is now in the bundle and settles it: 'Treatment of bleeding in patients with congenital hypo-, or afibrinogenaemia with bleeding tendency.' The product is Riastap, the first brand named on this page, and the route (intravenous) and drug class (human plasma fibrinogen concentrate) are the page's own — so the dose above is published, scoped explicitly to the congenital indication inside the dose text. REFERENCE LEVELS (§4.2, verbatim): 'Normal plasma fibrinogen level is in the range of 1.5 - 4.5 g/l. 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 page's second brand, Fibryga (Octapharma), was not fetched and none of its posology is represented here. THROMBOSIS (§4.4): 'There is a risk of thrombosis when patients with congenital deficiency are treated with human fibrinogen concentrate, particularly with high dose or repeated dosing.' SODIUM (§4.4): 'Riastap contains up to 164 mg (7.1 mmol) sodium per vial. This correlates with 11.5 mg (0.5 mmol) sodium per kg body weight of the patient if the recommended initial dose of 70 mg/kg body weight is applied.' INTERACTIONS (§4.5): 'No interactions of human plasma fibrinogen concentrate with other medicinal products are known.'

Paediatric dose

Dose: 70 mg/kg
Route: Intravenous infusion or injection after reconstitution, as for adults — warmed to room or body temperature and given slowly, 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; the target level determines duration (at least three days for minor events, seven days for major events)
Max: No paediatric maximum is stated. As in adults, 70 mg/kg is the INITIAL dose used when the fibrinogen level is unknown, not a ceiling.
THIS IS THE LABEL'S OWN PAEDIATRIC INSTRUCTION, NOT A SCALED ADULT FIGURE. §4.2, 'Dosage for neonates, infants and children', verbatim: '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.' The adult recommendation it points to is 70 mg per kg of body weight intravenously when the fibrinogen level is not known; where the level is known, calculate the individual dose from it rather than giving a flat 70 mg/kg. SCOPE: congenital hypo- or afibrinogenaemia with bleeding tendency only — the same limit as the adult dose. §4.4 names neonates among the groups in whom 'the potential benefit of treatment with human plasma fibrinogen concentrate should be weighed against the risk of thromboembolic complications' with caution and close monitoring. Confirm any paediatric use against a children's formulary and specialist haematology advice.

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 INSTRUCTION, NOT A SCALED ADULT FIGURE. §4.2, 'Dosage for neonates, infants and children', verbatim: '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.' The adult recommendation it points to is 70 mg per kg of body weight intravenously when the fibrinogen level is not known; where the level is known, calculate the individual dose from it rather than giving a flat 70 mg/kg. SCOPE: congenital hypo- or afibrinogenaemia with bleeding tendency only — the same limit as the adult dose. §4.4 names neonates among the groups in whom 'the potential benefit of treatment with human plasma fibrinogen concentrate should be weighed against the risk of thromboembolic complications' with caution and close monitoring. Confirm any paediatric use against a children's formulary and specialist haematology advice.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to the active substances or to any of the excipients listed in section 6.1 — this is the only contraindication stated in §4.3 of this SPC

Side effects

  • Thromboembolic events (common in the pooled aortic-surgery trials) — isolated cases have been fatal; see the thrombosis warning in §4.4
  • Pyrexia (very common in the pooled aortic-surgery trials)
  • Anaphylactic reactions, including anaphylactic shock (uncommon)
  • Allergic reactions, including generalised urticaria, rash, dyspnoea, tachycardia, nausea, vomiting, chills, pyrexia, chest pain, cough and blood pressure decreased (frequency unknown — post-marketing)
  • Note on frequencies: they are based on pooled analyses of two placebo-controlled trials in aortic surgery (n=61 and n=152). The SPC states that, because those trials were conducted in only the narrow population of aortic surgery, the rates observed may not reflect clinical practice and are unknown for clinical settings outside the studied indication

Monitoring

  • Determine the (functional) fibrinogen level before dosing wherever possible — it is what the individual dose is calculated from
  • Measure plasma fibrinogen level regularly and monitor the clinical condition continuously to set the amount and frequency of subsequent doses
  • In major surgical intervention, precise monitoring of replacement therapy by coagulation assays is essential
  • Observe patients closely for signs or symptoms of thrombosis — the risk is greatest with high dose or repeated dosing in congenital deficiency
  • Weigh benefit against the risk of thromboembolic complications, with 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; in case of anaphylactic shock, implement standard medical treatment for shock
  • Record the product name and batch number 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 fibrinogen, the substrate that thrombin converts to fibrin to form the stabilising mesh of a blood clot, thereby restoring effective clot formation when fibrinogen is deficient.

Prescribing in practice

  • Thromboembolic events can occur, particularly with high or repeated dosing, so use the lowest effective dose and weigh the risk in patients with thrombotic predisposition.
  • Dosing should be guided by measured fibrinogen levels and the clinical bleeding state rather than given empirically.
  • As a plasma-derived product it carries a theoretical transmissible infection risk and allergic or hypersensitivity reactions may occur during infusion.

Monitoring

Guide replacement with fibrinogen assays and clinical response, and observe for thrombotic and hypersensitivity reactions during and after administration.

Counselling the patient

  • This is a clotting factor given by infusion to help blood clot normally.
  • Report any chest pain, leg swelling, breathlessness or signs of a reaction during treatment.
  • It is prepared from human plasma and screened to minimise infection risk.

Evidence & guidelines

Fibrinogen concentrate is established for congenital fibrinogen deficiency and is used in acquired hypofibrinogenaemia, including major haemorrhage protocols, with thrombosis a recognised risk.

Reference: WOMAN Trial (Lancet 2017); RCOG PPH Guidelines 2022; BSH Transfusion Guidelines; Confirm identity and dosing against the manufacturer SPC (eMC) and NICE. 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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