Enoxaparin Sodium
Enoxaparinum natricum
Also known as: Lovenox · Clexane · Decipar · Klexane · Plaucina · Trombenox · Enoxaparinum natricum · PK10169 · RP-54563 · Low molecular weight heparin · LMWH
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceThromboprophylaxis (extra-label)
Verified clinician required
- q6-12h
NA
Governing clinical context (2)
- The commercially available injection should be stored at room temperature (25°C [77°F]); excursions permitted to 15°C to 30°C (59°F-86°F).
- One study showed that diluting the 100 mg/mL commercially available solution with sterile water to 20 mg/mL resulted in a product that was stable for 4 weeks when stored in a glass vial or in plastic syringes at room temperature or refrigerated. 18
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Enoxaparin is a low molecular weight heparin (LMWH) used primarily for the prophylaxis and treatment of thromboembolic disease, such as deep vein thrombosis (DVT), pulmonary embolism (PE), and feline aortic thromboembolism (FATE).
Compared to standard unfractionated heparin (UFH), LMWHs like enoxaparin offer a more predictable pharmacokinetic profile and preferentially inhibit Factor Xa over thrombin. This selective action means that standard coagulation tests (like aPTT) are not significantly prolonged, making hemorrhage less likely but also making monitoring more specialized.
Clinical Pearls:
- While LMWHs are theoretically safer and more predictable than UFH in humans, their rapid clearance in dogs and cats necessitates frequent subcutaneous dosing (often every 6 hours).
- This frequent dosing schedule, combined with the high cost of the medication, can make long-term management challenging in veterinary medicine, particularly for large dogs or horses.
- Recent studies in cats suggest that anti-Xa activity levels may not perfectly correlate with actual antithrombotic efficacy, complicating therapeutic monitoring.
Mechanism of action
Enoxaparin exerts its anticoagulant effect by binding to and accelerating the activity of antithrombin III (ATIII).
- The enoxaparin-ATIII complex preferentially inhibits Factor Xa (→ blocking the conversion of prothrombin to thrombin in the coagulation cascade).
- Because of its smaller molecular size compared to unfractionated heparin, enoxaparin has minimal impact on thrombin (Factor IIa).
- This selective anti-Xa activity prevents clot formation and extension without significantly altering standard clotting times (TT or aPTT).
Safety & warnings
Contraindications
- Hypersensitivity to enoxaparin, other LMWHs, heparin, or porcine products
- Intramuscular (IM) or Intravenous (IV) administration (must be given SC only)
Adverse effects
- Hemorrhage (unlikely but possible)
- Injection site hematoma
- Anemia
- Thrombocytopenia
- Nausea
- Fever
- Asymptomatic, reversible increases in AST or ALT
Precautions
Use cautiously in patients with significant renal dysfunction, as drug accumulation could result.
Important: Do NOT administer via IM or IV routes; enoxaparin must be given via deep subcutaneous injection only. Enoxaparin cannot be used interchangeably with other LMWHs (e.g., dalteparin) or unfractionated heparin sodium because the dosages and anti-Xa activities differ for each product.
Drug interactions
Increased risk for hemorrhage
Increased risk for hemorrhage
Increased risk for hemorrhage
Increased risk for hemorrhage
Monitoring
- CBC (with platelet count); baseline and ongoing during therapy
- Urinalysis
- Stool occult blood test
- Factor Xa activity (useful if bleeding occurs or patient has renal dysfunction)
- Note: Routine coagulation tests (aPTT, PT) are usually insensitive measures of activity and usually not warranted
Pharmacokinetics
Half-life
Absorption
After SC injection in humans, absorbed rapidly with a bioavailability of about 92%; peak plasma levels (activity) occur in 3-5 hours.
Distribution
Anti-factor Xa activity persists for up to 24 hours in humans, but duration is significantly shorter in dogs and cats.
Metabolism
Metabolized in the liver.
Elimination
Excreted in the urine as both unchanged drug and metabolites.
Overdose
Overdosage may lead to hemorrhagic complications.
If treatment is necessary, protamine sulfate may be administered via slow IV as an antidote.
- Dose: 1 mg of protamine sulfate can inhibit the effects of 1 mg of enoxaparin.
Available products
Formulations
- Injection (prefilled syringes)
- Injection (multidose vials)
Human-labeled
- Enoxaparin Sodium for Injection: 30 mg/0.3 mL, 40 mg/0.4 mL, 60 mg/0.6 mL, 80 mg/0.8 mL, 100 mg/1 mL, 120 mg/0.8 mL, & 150 mg/1 mL preservative free in single-dose prefilled syringes
- Enoxaparin Sodium for Injection: 300 mg/3 mL containing 15 mg/mL benzyl alcohol in 3 mL multidose vials (Lovenox)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store commercially available injection at room temperature (25°C, 77°F); excursions permitted to 15-30°C (59-86°F). Diluting 100 mg/mL solution with sterile water to 20 mg/mL is stable for 4 weeks when stored in a glass vial or plastic syringes at room temperature or refrigerated.
Client information
Enoxaparin is a blood thinner used to prevent or treat dangerous blood clots.
- Administration: This medication must be given by subcutaneous (under the skin) injection. Your veterinarian will teach you the proper injection technique. If not using prefilled syringes, use a very small gauge insulin or tuberculin syringe (e.g., 27 gauge).
- Strict Schedule: It is critical to give this medication exactly as prescribed. If doses are missed or delayed, life-threatening blood clots may form.
- Watch for Bleeding: Because this drug prevents clotting, there is a risk of bleeding. Immediately report any signs of bleeding (e.g., pale gums, bruising, nosebleeds, dark/tarry stools, or blood in the urine) to your veterinarian.
- Watch for Clots: Report any sudden weakness, paralysis (especially in the hind legs of cats), pain, or difficulty breathing, as these may be signs of a new blood clot.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.