Indications

In the UK, enoxaparin is approved for five indications:

The prophylaxis of thromboembolism disorders of venous origin, in particular those which may be associated with orthopaedic surgery. There is limited evidence supporting the use of enoxaparin in orthoapedic patients, although evidence is reasonable for colorectal patients
The prophylaxis of venous thromboembolism (VTE) in medical patients bedridden due to acute illness.
The treatment of venous thromboembolism disease (VTED) presenting with deep vein thrombosis (DVT), pulmonary embolism (PE) or both.
The treatment of unstable angina (UA) and non-Q-wave myocardial infarction (NQMI), administered concurrently with aspirin.
The prevention of thrombus formation in the extracorporeal circulation during haemodialysis.

In the United States, enoxaparin is FDA approved for eight indications:

Prophylaxis of DVT in medically ill patient,
Total hip & knee replacement,
Extended hip-replacement,
Abdominal surgery.
Treatment of DVT with or without PE inpatient and
Treatment of DVT inpatient, with ACS, including STEMI.

Mechanism of action

Enoxaparin binds to and accelerates the activity of antithrombin III. By activating antithrombin III, enoxaparin preferentially potentiates the inhibition of coagulation factors Xa and IIa. The anticoagulant effect of enoxaparin can be directly correlated to its ability to inhibit factor Xa. Factor Xa catalyzes the conversion of prothrombin to thrombin, so enoxaparin’s inhibition of this process results in decreased thrombin and ultimately the prevention of fibrin clot formation.

Monitoring

Enoxaparin does not affect the INR, PT or aPTT
Anti-factor Xa levels can be measured, and are often used to monitor enoxaparin activity

Pregnancy

Category B: enoxaprin is safe for use in the second trimester as it does not cross the placenta and safe while breast feeding

Side effects

Bleeding
Thrombocytopenia, i.e. can be associated with heparin-induced thrombocytopenia (0.5-5.0% of patients treated for at least five days
Pain, bruising or irritation; hard, inflamed nodules or an itchy red rash at the injection site
Symptoms similar to those of hayfever
Abdominal/chest pain
Headache

Reversal Agent

Protamine, although not as effective at reversal as it is for heparin due to more activity at the Xa clotting factor (enoxaparin); as heparin has both Xa and IIa. Protamine sulfate will reverse enoxaparin by 66% per package insert.