Tranexamic acid
A synthetic lysine analogue that stops clots being broken down, used for heavy periods, bleeding in hemophilia and postpartum hemorrhage.
Also called TXA (abbreviation).
Drug card
- Class
- Antifibrinolytic
- How it works
- Blocking plasminogen's lysine sites, so clots are not broken down
- Used for
- Heavy menstrual bleeding
- Bleeding in hemophilia (tooth extraction) and nosebleeds
- Postpartum hemorrhage
- Known for
- Venous and arterial clots
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does tranexamic acid work?
A synthetic lysine derivative. Binding to plasminogen's one high-affinity lysine site pulls plasminogen off fibrin, and plasmin that still forms cannot latch on to fibrin, so the clot's fibrin framework survives. It is about ten times as potent as aminocaproic acid and lasts longer.
Uses
What is tranexamic acid used for?
- Heavy menstrual bleeding
- Bleeding in hemophilia (tooth extraction) and nosebleeds
- Postpartum hemorrhage
Side effects
Side effects of tranexamic acid
- Venous and arterial clotsKnown forSerious
- Retinal vessel occlusion and altered color visionSerious
- SeizuresSerious
- AnaphylaxisSerious
- Headache
- Sinus and nasal symptoms
- Back pain
- Abdominal pain
- Joint and muscle pain
- Nausea, vomiting and diarrhea
- Dizziness
- Low blood pressure with rapid injection
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Contraindicated with combined hormonal contraceptives and with active or past thrombosis or a high clot risk, including retinal vessel occlusion.
- The injection is for IV use only; given by the neuraxial route in error it has caused seizures, arrhythmias and death.
- Tissue plasminogen activators and tranexamic acid weaken each other; factor IX complex concentrates raise the clot risk.
- Visual or eye symptoms: stop it and arrange a full eye examination.
Good to know: WHO recommends it for treating postpartum hemorrhage; in the US the tablets are licensed for heavy periods and the injection for bleeding in hemophilia.
Remember it
A way to remember it
Tranexamic acid is a lysine look-alike: it fills plasminogen's lysine slots, so plasmin cannot grip fibrin and the clot holds.
It is the mirror image of the thrombolytics, which make plasmin to dissolve clots; given together, each weakens the other.
Written for biofideX
Its class
Antifibrinolytics
These lysine analogues (tranexamic acid, aminocaproic acid) occupy the lysine-binding sites of plasminogen. Plasminogen is pushed off the fibrin surface, and any plasmin formed cannot attach to fibrin, so the fibrin mesh is not dissolved and clots that seal bleeding vessels hold. At higher concentrations tranexamic acid also inhibits plasmin directly.
Easily mixed up with thrombolytics.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Tranexamic acid tablets: label (DailyMed)
- Tranexamic acid injection: label (DailyMed)
- Tranexamic Acid (NCI Thesaurus)
- About tranexamic acid (NHS)
- WHO recommendation on tranexamic acid for the treatment of postpartum haemorrhage (WHO)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Blood clots and cholesterol
Tranexamic acid is one of 19 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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