To the Editor: The Guidelines for the management of acute coronary syndromes 20061 state: “Enoxaparin may be used in conjunction with fibrin-specific fibrinolytic agents in patients under the age of 75 years, provided they do not have significant renal dysfunction. An intravenous bolus dose of 30 mg followed by a 1 mg/kg subcutaneous injection every 12 hours in combination with tenecteplase is the most comprehensively studied therapy.”1

In Australia, enoxaparin is not licensed for intravenous use (Tony Hall, Team Leader, High Risk Medications and Systems, and Christine Maclean, Associate Director, Safe Medication Practice Unit, Queensland Health, personal communication) and there is no recommendation for the intravenous use of enoxaparin in the drug product information.2 Are the authors recommending “off-label” use of intravenous enoxaparin, or do they wish to modify the guidelines to reflect what the management should be if clinicians are unable to use intravenous enoxaparin?

In reply: The guidelines were published to provide clinicians with the most contemporary information on the management of acute coronary syndromes based on the international literature, and may include treatments which are not currently available, officially licensed or available through the Pharmaceutical Benefits Scheme in Australia.

In the context of adjuvant therapy for patients with ST-segment-elevation myocardial infarction (STEMI), the guidelines recommend that antithrombin therapy should be used with fibrin-specific fibrinolytic agents.1 Based on the best evidence available at the time, the guidelines mention two antithrombins, unfractionated heparin and enoxaparin, to be considered for use in this setting. The recommendation for enoxaparin is based on comprehensive evidence of clinical benefit with the regimen of an initial intravenous (IV) bolus dose followed by subcutaneous injections every 12 hours. It is up to individual practitioners to determine whether the IV dose should be provided “off-label” or omitted, based on the evidence and the circumstances of the individual patient and setting.

The issue of superiority of enoxaparin over unfractionated heparin as adjuvant therapy for patients with STEMI is currently being evaluated in light of recent evidence,2 and will be included in a future update of the guidelines.