Clexane (Enoxaparin) Dosing for NSTEMI
For NSTEMI patients, administer enoxaparin 1 mg/kg subcutaneously every 12 hours, continued throughout hospitalization or until PCI is performed, with dose reduction to 1 mg/kg once daily if creatinine clearance is below 30 mL/min. 1, 2
Standard Dosing Protocol
The core regimen is 1 mg/kg subcutaneous injection every 12 hours for all NSTEMI patients with normal to moderately impaired renal function 1, 2
An optional 30 mg intravenous bolus may be given initially in selected patients, though this is not universally required and should be reserved for specific clinical scenarios 1, 2
Continue enoxaparin for the entire duration of hospitalization or until percutaneous coronary intervention is performed 1, 2
Critical Renal Dose Adjustments
You must calculate creatinine clearance before initiating enoxaparin in every NSTEMI patient, as renal impairment dramatically affects drug clearance and bleeding risk 2, 3
For creatinine clearance <30 mL/min: reduce to 1 mg/kg subcutaneously once daily (not twice daily) 1, 2
For creatinine clearance 30-50 mL/min: research suggests considering dose reduction to 0.8 mg/kg every 12 hours to prevent drug accumulation, though guidelines maintain standard dosing 3
Enoxaparin clearance decreases by 31% in moderate renal impairment and 44% in severe renal impairment, leading to significant drug accumulation with standard dosing 3
Management at Time of PCI
The timing between your patient's last enoxaparin dose and PCI determines whether additional anticoagulation is needed:
If PCI occurs within 8 hours of last subcutaneous dose: give no additional enoxaparin (adequate anticoagulation already present) 1, 2
If PCI occurs 8-12 hours after last dose: administer 0.3 mg/kg IV enoxaparin at the time of PCI 1, 2
If PCI occurs >12 hours after last dose: treat as de novo anticoagulation with full-dose regimen 1, 2
Critical Safety Warning: Never "Stack" Anticoagulants
Do not administer unfractionated heparin to patients already receiving enoxaparin - this "stacking" significantly increases major bleeding complications 1, 2
The SYNERGY trial demonstrated that patients on upstream enoxaparin who received additional UFH at PCI had substantially increased bleeding rates 1, 2
If switching anticoagulants is absolutely necessary, allow appropriate washout periods, though switching in either direction increases bleeding risk 2
Evidence Quality and Strength
These recommendations carry Class I, Level of Evidence A designation from the 2014 ACC/AHA guidelines, meaning enoxaparin is definitively indicated for NSTEMI patients requiring anticoagulation 2
The dosing strategy is supported by multiple large randomized trials including ESSENCE and TIMI-11B, which demonstrated superior or equivalent efficacy compared to unfractionated heparin with similar or lower bleeding rates 4, 5
Common Pitfalls to Avoid
Failing to check renal function before dosing - this is the most common error leading to drug accumulation and bleeding 2, 3
Administering UFH during PCI to patients already on enoxaparin 1, 2
Using twice-daily dosing in patients with severe renal impairment 1, 2
Giving additional enoxaparin at PCI when the last dose was within 8 hours 1, 2