CV: Antifibrinolytics

Question 1

Fibrin dissolution can be impaired by the administration of what drug used in the management of menorrhagia?

Answer 1

Fibrin dissolution can be impaired by the administration of tranexamic acid, which inhibits fibrinolysis. It can be used to prevent bleeding or to treat bleeding associated with excessive fibrinolysis (e.g. in surgery, dental extraction, obstetric disorders, and traumatic hyphaema) and in the management of menorrhagia

Question 2

Other than menorrhagia, what else can tranexamic acid be used for?

Answer 2

Hereditary angioedema ( a drug which can cause non-heredirary angioedema would be an ACEI), epistaxis, and in thrombolytic overdose.

Question 3

What is the OTC indication for tranexamic acid? (4)

Answer 3

1. Heavy menstrual bleeding over SEVERAL cycles
2. 18+
3. Regular 21-35 day cycles
4. No more than 3 days individual variability in cycle duration.

Question 4

What are the contraindications to OTC tranexamic acid use? (4)

Answer 4

1. unopposed oestrogen or tamoxifen.
2. Obesity/diabetes
3. Breastfeeding
4. PCOS or a history of endometrial cancer in 1* relative.

Question 5

Desmopressin is an analogue of vasopressin which is used for: diabetes insipidus, primary nocturnal enuresis, renal function test and what conditions relevant to fibrinolytics?

Answer 5

Mild to moderate haemophilia and vo Willebrand’s disease:

Also used in fibrinolytic response testing.

Question 6

Etamsylate reduces capillary bleeding in the presence of normal number of platelets and it does not act by fibrin stabilisation. How does it probably work?

Answer 6

Correcting abnormal adhesion: not recommeded use for heavy menstrual bleeding any longer.

Question 7

How does desmopressin function as an antifibrinolytic drug?

Answer 7

It increases the plasma concentration of the pro-coagulant Willebrand factor.

Question 8

How does tranexamic acid work?

Answer 8

It inhibits the activation of plasminogen which is normally responsible for clot breakdown.