Streptokinase

It is an extracellular protein.

Production:
It is obtained from cultured medium of group C-β hemolytic streptococci.

Mechanism of action:
It causes the conversion of plasminogen to plasmin. It causes the degradation of fibrinogen.
It also results in the breakdown of factor V and VII.

Pharmacokinetics:
Its half life is half an hour. It is administered within 4 hours of myocardial infarction and is infused for 1 hour.

Therapeutic uses:
It is used for reopening of occluded shunts, arterial and deep vein thrombosis and acute myocardial infarction (in addition with aspirin this effect is increased).

Dosage:
Its loading intravenous dose is 2, 50,000 units. Then it will be given as a continuous infusion of 100,000 units per hour for 24-72 hours.

Adverse effects:
It may cause hemorrhage. In severe cases of hemorrhage, aminocaproic acid can be given as an antidote.

Hypersensitivity reactions can also be developed such as rashes, fever and anaphylaxis. Antibodies developed due to streptococcal infection in some peoples may neutralize fibrinolytic properties of streptokinase. These antistreptococcal antibodies may cause fever, allergy and treatment ineffectiveness. In that case of treatment ineffectiveness more amount of streptokinase is to be administered.

Fever and shivering have also been observed in 1-4% of patients.