| Low Molecular Weight Heparins should not be used interchangeably since they differ in their manufacturing process, molecular weights, specific anti Xa activities, units and dosage. This results in differences in pharmacokinetics and associated biological activities (e.g. anti-IIa activity, and platelet interactions). Special attention and compliance with the instructions for use specific to each proprietary medicinal product are therefore required.Enoxaparin is to be used with extreme caution in patients with a history of heparin-induced thrombocytopenia with or without thrombosis.As there is a risk of antibody-mediated heparin-induced thrombocytopenia also occurring with low molecular weight heparins, regular platelet count monitoring should be considered prior to and during therapy with these agents. Thrombocytopenia, should it occur, usually appears between the 5th and the 21st day following the beginning of therapy. Therefore, it is recommended that the platelet counts be measured before the initiation of therapy with enoxaparin sodium and then regularly thereafter during the treatment. In practice, if a confirmed significant decrease of the platelet count is observed (30 to 50 % of the initial value), enoxaparin sodium treatment must be immediately discontinued and the patient switched to another therapy.Enoxaparin injection, as with any other anticoagulant therapy, should be used with caution in conditions with increased potential for bleeding, such as: impaired haemostasis, history of peptic ulcer, recent ischaemic stroke, uncontrolled severe arterial hypertension, diabetic retinopathy, recent neuro- or ophthalmic surgery.As with other anticoagulants, bleeding may occur at any site (see section 4.8 Undesirable effects). If bleeding occurs, the origin of the haemorrhage should be investigated and appropriate treatment instituted.Heparin can suppress adrenal secretion of aldosterone leading to hyperkalaemia, particularly in patients such as those with diabetes mellitus, chronic renal failure, pre-existing metabolic acidosis, a raised plasma potassium or taking potassium sparing drugs. The risk of hyperkalaemia appears to increase with duration of therapy but is usually reversible. Plasma potassium should be measured in patients at risk before starting heparin therapy and monitored regularly thereafter particularly if treatment is prolonged beyond about 7 days.As with other anticoagulants, there have been cases of intra-spinal haematomas reported with the concurrent use of enoxaparin sodium and spinal/epidural anaesthesia or spinal puncture resulting in long term or permanent paralysis. These events are rare with enoxaparin sodium dosage regimens, use of post-operative indwelling catheters or the concomitant use of additional drugs affecting haemostasis such as NSAIDs (see section 4.5 Interaction with other medicinal products and other forms of interaction). The risk also appears to be increased by traumatic or repeated neuraxial puncture or in patients with a history of spinal surgery or spinal deformity.To reduce the potential risk of bleeding associated with the concurrent use of enoxaparin sodium and epidural anaesthesia/analgesia, the pharmacokinetic profile of the drug should be considered (see section 5.2 Pharmacokinetic properties). Placement and removal of the catheter is best performed when the anticoagulation effect of enoxaparin is low.Placement or removal of a catheter should be delayed for 10 to 12 hours after administration of DVT prophylactic doses of enoxaparin sodium, whereas patients receiving higher doses of enoxaparin sodium (1.5 mg/kg once daily) will require longer delays (24 hours). The subsequent enoxaparin sodium dose should be given no sooner than 4 hours after catheter removal.Should the physician decide to administer anticoagulation in the context of epidural/spinal anaesthesia, extreme vigilance and frequent monitoring must be exercised to detect any signs and symptoms of neurological impairment such as midline back pain, sensory and motor deficits (numbness or weakness in lower limbs), bowel and/or bladder dysfunction. Patients should be instructed to inform their nurse or physician immediately if they experience any of the above signs or symptoms. If signs or symptoms of spinal haematoma are suspected, urgent diagnosis and treatment including spinal cord decompression should be initiated.The Multidose vial contains benzyl alcohol as a preservative and should not be given to premature babies or neonates. The administration of medicines containing benzyl alcohol as a preservative may cause toxic reactions and anaphylactoid reactions in children up to 3 years old.Percutaneous coronary revascularisation procedures: To minimise the risk of bleeding following vascular instrumentation during the treatment of unstable angina, non-Q-wave myocardial infarction and acute ST-elevation myocardial infarction, adhere precisely to the intervals recommended between enoxaparin sodium doses. It is important to achieve homeostasis at the puncture site after PCI. If a closure device is used, the sheath can be removed immediately. If a manual compression method is used, sheath should be removed 6 hours after the last IV/SC enoxaparin sodium injection. If the treatment is continued, the next scheduled dose should be given no sooner than 6 to 8 hours after sheath removal. The site of the procedure should be observed for signs of bleeding or haematoma formation. For some patients with pulmonary embolism (e.g. those with severe haemodynamic instability) alternative treatment such as thrombolysis or surgery may be indicated.Prosthetic Heart Valves:There have been no adequate studies to assess the safe and effective use of enoxaparin sodium in preventing valve thrombosis in patients with prosthetic heart valves. Prophylactic doses of enoxaparin are not sufficient to prevent valve thrombosis in patients with prosthetic heart valves. Confounding factors, including underlying disease and insufficient clinical data, limit the evaluation of these cases. Therapeutic failures have been reported in pregnant women with prosthetic heart valves on full anti-coagulant doses (see section 4.6 Pregnancy and lactation). The use of enoxaparin sodium cannot be recommended for this purpose.Haemorrhage in the elderly: No increased bleeding tendency is observed in the elderly within the prophylactic dosage ranges. Elderly patients (especially patients aged eighty years and above) may be at an increased risk for bleeding complications within the therapeutic dosage ranges. In the treatment of acute ST-segment Elevation Myocardial Infarction (STEMI), an increase in bleeding events was observed in patients aged 65-75 years suggesting these patients might be at particular risk of bleeding. Careful clinical monitoring is advised (see also section 4.2 Posology and method of administration: Elderly; section 5.2 Pharmacokinetic properties).Renal impairment: In patients with renal impairment, there is an increase in enoxaparin exposure which increases the risk of bleeding. Since enoxaparin exposure is significantly increased in patients with severe renal impairment (creatinine clearance < 30 ml/min) dosage adjustments are recommended in therapeutic and prophylactic dosage ranges. Although no dosage adjustments are recommended in patients with moderate (creatinine clearance 30-50 ml/min) and mild (creatinine clearance 50-80 ml/min) renal impairment, careful clinical monitoring is advised (see also section 4.2 Posology and method of administration: Renal impairment; section 5.2 Pharmacokinetic properties). In the treatment of acute ST-segment Elevation Myocardial Infarction (STEMI), the data are limited in patients with creatinine levels above 220 and 175 µmol/L for males and females respectively.Low body weight: In low-weight women (< 45 kg) and low-weight men (< 57 kg), an increase in enoxaparin exposure has been observed within the prophylactic dosage ranges (non-weight adjusted), which may lead to a higher risk of bleeding. Therefore, careful clinical monitoring is advised in these patients (see also section 5.2 Pharmacokinetic properties).Monitoring: Risk assessment and clinical monitoring are the best predictors of the risk of potential bleeding. Routine anti-Xa activity monitoring is usually not required. However, anti-Xa activity monitoring might be considered in those patients treated with LMWH who also have either an increased risk of bleeding (such as those with renal impairment, elderly and extremes of weight) or are actively bleeding.Laboratory tests:At doses used for prophylaxis of venous thromboembolism, enoxaparin sodium does not influence bleeding time and global blood coagulation tests significantly, nor does it affect platelet aggregation or binding of fibrinogen to platelets. At higher doses, increases in APTT (activated partial thromboplastin time) and ACT (activated clotting time) may occur. Increases in APTT and ACT are not linearly correlated with increasing enoxaparin sodium antithrombotic activity and therefore are unsuitable and unreliable for monitoring enoxaparin sodium activity. | |