<prompt> Which of the following Fibrinolytic is antigenic?UrokinaseAlteplaseTenecteplaseStreptokinase  <response>: The clinically important fibrinolytic are:1. Streptokinase2. Urokinase3. Alteplase rt-PA4. Reteplase5. TenecteplaseStreptokinase:It is obtained from Beta hemolytic Streptococci group C.It is inactive as such: combines with circulating plasminogen to form an activator complex which then causes limited proteolysis of other plasminogen molecules to plasmin.Antistreptococcal antibodies present due to past infections inactivate a considerable fraction of the initial dose of Stk: a loading dose is necessary for the beginning. Its t12 is estimated to be 30-80 min.Streptokinase is antigenic; can cause hypersensitivity reactions and anaphylaxis, especially when used second time in a patient.Repeat doses are also less effective due to neutralization by antibodies. Fever is common, hypotension and arrhythmias are reported. 