fibrinolytics and antifibrinolytics

FIBRINOLYTICS

By Dr. Md Yaqub

These are the drugs used to lyse thrombi/ clot to recanalize occluded blood vessels (mainly coronary artery).

They act by activating natural fibrinolytic system

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• The process of dissolution of clot is called fibrinolysis

• Egs:- Streptokinase• Urokinase• Alteplase• Reteplase• Tenecteplase

StreptokinaseObtained from -hemolytic streptococci group C. Binds with circulating plasminogen to form complex that

activates plasminogen to plasmin

Its non fibrin specific. i.e. activates both circulating as well as fibrin bound plasminogen. Predisposes to bleeding

It is least expensive

It is destroyed by circulating antistreptococcal antibodies

Stk is antigenic- hypersensitivity reaction, anaphylaxis in 1-2%.

Adverse effects:- Fever, hypotension, allergic reactions, arrhythmias can occur.

Urokinasehuman urine, human kidney cells.

Non antigenic, not destroyed by antibodies.

Adverse effects:-Hypotension and allergic phenomenon are rare. Fever can occur

Alteplase (rt-PA)recombinant DNA technologyfibrin specificNon antigenic, non-pyrogenic, not destroyed by

antibodies,Rapid acting, more potentNausea, mild hypotension, fever may occur More effective, more Expensive Low risk of bleeding and allergic reactions

USES of fibrinolytics1. ACUTE MYOCARDIAL INFARCTION

2. Deep vein thrombosis

3. Pulmonary embolism

4.Peripheral arterial occlusion

5. Acute Ischemic Stroke

Contraindications to thrombolytic therapy1. Intracranial hemorrhage2. Head injury/major surgery in past 3

months3. Intracranial tumors/vascular

abnormality/aneurysms4. Active bleeding/bleeding disorders5. Peptic ulcer6. Any wound or recent fracture or tooth

extraction7.Severe Hypertension

ANTIFIBRINOLYTIC DRUGS

These are drugs which blocks the conversion of plasminogen to plasmin & thus inhibit fibrinolytic activity.

Egs:- Epsilon amino-caproic acid (EACA) Tranexamic acid.

Epsilon amino-caproic acid (EACA)Inhibits plasminogen to plasmin convertion,

hence prevents clot lysis It is a specific antidote for fibrinolytic agents In haemophiliacs, it has adjunctive value for

controlling bleeding due to tooth extraction, prostatectomy, trauma, etc.

Tranexamic acid

It is 7 times more potent than EACA, more commonly used.

Oral, i.v, topical administrationIn dentistry, tranexamic acid soaked guaze or

mouthwash is used to reduce bleeding postoperatively in hemophiliacs and pts on anticoagulants

• Antidote for Fibrinolytic drugs.• In Cardio-pulmonary bypass surgery.• Tonsillectomy, prostatic surgery, tooth extraction• Menorrhagia• Recurrent epistaxis, peptic ulcer.

USES OF ANTIFIBRINOLYTIC DRUGS