Fibrinolytic therapy is indicated if there is prolonged ischaemic chest pain that has begun within the previous 12 hours, in the presence of significant ST segment elevation or left bundle branch block (that is presumed new). Whether or not fibrinolytic therapy should be given to patients who give a history of pain starting between 12 and 24 hours is a matter of clinical judgment. It should be considered if there is evidence of ongoing ischaemia (ongoing chest pain with ST segment elevation) or recurrence of pain with ST elevation, or if there is a stuttering onset of pain.

Contraindications to fibrinolytic therapy for patients with STEMI (see Box 3.8) can be absolute or relative. Patients with an absolute contraindication should be transferred for a percutaneous coronary intervention where possible. With relative contraindications, the risks and benefits of treatment must be weighed.

Use one of the following fibrinolytic drugs:

Plasminogen activators (alteplase, reteplase and tenecteplase) are superior to streptokinase, but considerably more expensive. The bolus drugs reteplase (double bolus) and tenecteplase (single bolus) have major advantages in terms of convenience and could be used in the pre-hospital setting.

Because of a high incidence of neutralising antibodies, which persist indefinitely, streptokinase should not be used in Aboriginal and Torres Strait Islander patients or those who have received streptokinase more than three days previously.

Hypotension can occur, particularly with streptokinase, and should be treated by giving fluid, raising the foot of the bed and slowing the infusion rate.

Significant arrhythmias including ventricular fibrillation are not uncommon at the time of reperfusion. After the administration of thrombolytic therapy, patients should be closely monitored by staff trained in advanced life support and defibrillation.

Allergic reactions are common with streptokinase; they include bronchospasm, periorbital swelling, angioedema, urticaria, itching, flushing, nausea, headache and musculoskeletal pain. Delayed hypersensitivity reactions such as vasculitis and interstitial nephritis have also been observed. Anaphylactic shock is rare.

For mild or moderate allergic reactions and fever, use:

For severe allergic reactions, immediately discontinue streptokinase and give:

If no response, increase to:

In patients in whom there is a contraindication to fibrinolytic therapy (see Box 3.8), or who are deemed to be high-risk, and where fibrinolytic therapy is felt unlikely to be effective (eg cardiogenic shock), primary coronary angioplasty is an effective therapy if resources are available or the patient can be promptly transferred to a centre where PCI is available.

Heparin should be administered with alteplase, reteplase and tenecteplase. The use of heparin with streptokinase is optional. Use:

Enoxaparin is not approved in Australia as an adjunct to fibrinolysis for STEMI. However, a recent clinical trial has demonstrated its efficacy in this situation. The trial protocol used a 30 mg intravenous bolus followed 15 minutes later by 1 mg/kg subcutaneously 12-hourly in patients younger than 75 years. In patients older than 75 years, the intravenous bolus was not given and the subcutaneous dose of enoxaparin was reduced to 0.75 mg/kg 12-hourly.

Occasionally bleeding may occur following treatment with fibrinolytic therapy and heparin. Intracranial haemorrhages are devastating and life-threatening. Systemic bleeding and gastrointestinal bleeding can occur. If this bleeding does occur: