Low molecular weight heparin (LMWH) Pregnancy: US label: placental transfer observed in animal studies; human data from a retrospective cohort (693 live births) suggest no increased risk of major developmental abnormalities. Pregnant women with mechanical prosthetic heart valves may be at higher risk for thrombosis.

Enoxaparin sodium

Brand names: Clexane, Inhixa

Enoxaparin is a low-molecular-weight heparin (LMWH) given by subcutaneous injection for venous-thromboembolism prevention and treatment and in acute coronary syndromes.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: VTE prophylaxis: 40 mg once daily (abdominal surgery / medical patients) or 30 mg every 12 hours (hip or knee replacement); DVT/PE treatment: 1 mg/kg every 12 hours OR 1.5 mg/kg once daily

Route: Subcutaneous injection (intravenous bolus component in acute STEMI)

Frequency: Once daily or every 12 hours depending on indication

US labelling. Evaluate for a bleeding disorder before starting (unless treatment urgently needed). Abdominal surgery prophylaxis: 40 mg SC once daily (first dose 2 hours pre-op), usual 7-10 days. Hip or knee replacement: 30 mg SC every 12 hours, first dose 12-24 hours post-op; alternatively 40 mg once daily may be considered for hip replacement for up to 3 weeks (first dose 12 +/- 3 hours pre-op). Medical patients during acute illness: 40 mg SC once daily for 6-11 days. DVT treatment: 1 mg/kg SC every 12 hours (outpatient, DVT without PE), or 1 mg/kg every 12 hours OR 1.5 mg/kg once daily for inpatient treatment; continue at least 5 days and until INR 2-3 with warfarin (average 7 days). Unstable angina/non-Q-wave MI: 1 mg/kg SC every 12 hours with oral aspirin (100-325 mg once daily), usual 2-8 days. Acute STEMI: single IV bolus 30 mg plus 1 mg/kg SC, then 1 mg/kg SC every 12 hours (max 100 mg for first two doses only); reduce dose in patients >=75 years. Safety and effectiveness in paediatric patients not established; not approved in neonates or infants.

Dose adjustments

Renal

Severe renal impairment (creatinine clearance <30 mL/min): prophylaxis 30 mg SC once daily; DVT/PE and unstable angina/NSTEMI treatment 1 mg/kg SC once daily; STEMI in patients <75 years 30 mg IV bolus then reduced regimen (source table truncated).

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

See full prescribing information for dosing and administration information. ( 2 ) 2.1 Pretreatment Evaluation Evaluate all patients for a bleeding disorder before starting enoxaparin sodium treatment, unless treatment is urgently needed. 2.2 Adult Dosage Abdominal Surgery The recommended dose of enoxaparin sodium is 40 mg by subcutaneous injection once a day (with the initial dose given 2 hours prior to surgery) in patients undergoing abdominal surgery who are at risk for thromboembolic complications. The usual duration of administration is 7 to 10 days [see Clinical Studies (14.1) ]. Hip or Knee Replacement Surgery The recommended dose of enoxaparin sodium is 30 mg every 12 hours …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-06-21. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Active major bleeding
History of immune-mediated heparin-induced thrombocytopenia (HIT) within the past 100 days or presence of circulating antibodies
Known hypersensitivity to enoxaparin sodium (e.g. pruritus, urticaria, anaphylactic/anaphylactoid reactions)
Known hypersensitivity to heparin or pork products

Side effects

Bleeding
Anaemia
Thrombocytopenia
Elevation of serum aminotransferase
Diarrhoea, nausea, ecchymosis, fever, oedema, injection site pain

Interactions

Anticoagulants, platelet inhibitors including acetylsalicylic acid, salicylates, NSAIDs (including ketorolac), dipyridamole, sulfinpyrazone: increased risk of haemorrhage; discontinue if possible before starting or conduct close monitoring
Neuraxial anaesthesia/spinal puncture: risk of epidural or spinal haematoma

Clinical monograph

How it works

It binds antithrombin to inhibit factor Xa (and, to a lesser extent, thrombin), preventing clot propagation.

Prescribing in practice

It accumulates in renal impairment — dose-reduce, and consider anti-Xa monitoring at extremes of body weight or renal function.
There is a risk of spinal/epidural haematoma if it is used around neuraxial (spinal/epidural) anaesthesia — observe the timing rules.
Heparin-induced thrombocytopenia (HIT) can occur (monitor platelets); protamine only partially reverses it.

Monitoring

Monitor renal function, platelet count (for HIT), anti-Xa in selected patients, and signs of bleeding.

Counselling the patient

It is a subcutaneous injection — technique is taught for home use.
Report bleeding or bruising.
Tell anaesthetists you take it before any spinal or epidural procedure.

Evidence & guidelines

Standard for VTE prophylaxis/treatment and ACS (NICE NG89/NG158).

Reference: NICE NG89; NICE NG158; RCOG GTG 37a/37b; BSH guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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