Antifibrinolytic — Surgical Haemostasis (Alternative to Tranexamic Acid) Pregnancy: Use with caution — limited data; TXA preferred if antifibrinolytic needed in pregnancy

Aminocaproic Acid

Brand names: Amicar

Adult dose

Dose: 4–5 g IV over 1 hour initially, then 1 g/hour infusion for up to 8 hours or until bleeding controlled

Route: Intravenous or oral

Frequency: Loading dose then continuous infusion

Max: 30 g/day

Less potent than tranexamic acid (6–10× less potent on a weight basis). Used where TXA unavailable or contraindicated. Oral formulation available for maintenance. In subarachnoid haemorrhage: used historically for rebleeding prevention (now largely replaced by early surgery/coiling). Avoid in haematuria — risk of ureteric clot obstruction.

Paediatric dose

Dose: 100 mg/kg loading dose IV mg/kg

Route: IV

Frequency: Loading then 33 mg/kg/hour infusion

Max: 18 g/m²/day

BNFc: used in paediatric haemostasis under specialist guidance; less evidence than TXA in children

Dose adjustments

Renal

Reduce dose in renal impairment — renally excreted; risk of accumulation and toxicity

Hepatic

Use with caution

Paediatric weight-based calculator

Patient weight (kg)

BNFc: used in paediatric haemostasis under specialist guidance; less evidence than TXA in children

Clinical pearls

Tranexamic acid is preferred in UK practice — 6–10× more potent, better trial evidence (CRASH-2, WOMAN, POISE-3), and oral TXA bioavailability is high (30–50%) vs aminocaproic acid being less well absorbed
Aminocaproic acid used mainly where TXA not available or in specific haematology protocols (e.g., haemophilia with inhibitors, SAH rebleeding prevention — historical)
Skeletal muscle myopathy can occur with prolonged high-dose use — monitor CK in extended courses
Both antifibrinolytics work via same mechanism: block lysine-binding sites on plasminogen, preventing plasmin formation and fibrin clot dissolution

Contraindications

Active intravascular clotting (DIC without concurrent heparin)
Haematuria of upper urinary tract origin
Subarachnoid haemorrhage (relative — clot obstruction risk)

Side effects

Nausea, vomiting, diarrhoea
Hypotension (rapid IV)
Dizziness
Skeletal muscle weakness and myopathy (prolonged use)
Rhabdomyolysis (rare)
Thromboembolism
Bradycardia
Nasal congestion

Interactions

Hormonal contraceptives — additive thrombotic risk
Factor IX complex concentrates — increased thrombosis risk
Tretinoin — increased thrombotic risk in APL

Monitoring

Renal function
CK (prolonged use — myopathy)
Coagulation screen
Signs of VTE
Blood pressure during IV loading

Reference: BNFc; BNF 90; MHRA SPC Amicar; BSH Perioperative Haemostasis Guidelines; Perioperative Antifibrinolytic Review. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways