Rare anaphylactic reactions can occur. Coronary thrombolysis may result in reperfusion arrhythmias. If serious bleeding occurs, infusion of streptokinase and heparin should be stopped. Occasionally severe hypotension can occur (not from bleeding or anaphylaxis). The following conditions increase the risk of bleeding: recent (within 10 days) major surgery, cerebrovascular disease, recent (within 10 days) GI or GU bleeding, recent trauma (within 10 days) including CPR, hypertension, high likelihood of left heart thrombus, acute pericarditis, subacute bacterial endocarditis, hemostatic defects including those caused by severe renal or hepatic dysfunction, significant hepatic dysfunction, diabetic hemorrhagic retinopathy or other hemorrhagic ophthalmic conditions, septic thrombophlebitis or occluded AV cannula at seriously infected site, and/or any other condition in which bleeding constitutes a significant hazard or would be particularly difficult to manage due to its location. Standard management for myocardic infarction should be followed while infusing streptokinase. Use with caution in patients receiving oral anticoagulants (risk of bleeding). Concurrent heparin anticoagulation may contribute to bleeding. Use with caution in elderly patients (higher risk of bleeding). Use with caution in pregnancy (increased risk of bleeding). Repeat administration with caution in patients who have received anistreplase or streptokinase within 1 year (streptokinase antibody may decrease effectiveness or risk of allergic reactions). Do not administer by I.M. injection. Patients who have had a recent streptococcal infection (within 6 months) may also manifest hypersensitivity to streptokinase.