# Enoxaparin: veterinary dose and monograph

> Enoxaparin is a veterinary drug. A LOW-MOLECULAR-WEIGHT HEPARIN (LMWH) anticoagulant used for prevention and treatment of THROMBOEMBOLISM — especially feline arterial thromboembolism (ATE) prophylaxis in cardiomyopathy, and thromboprophylaxis in dogs with IMHA… Indications include feline arterial thromboembolism (ATE) — treatment/prophylaxis in cardiomyopathy; thromboprophylaxis in hypercoagulable disease (IMHA, protein-losing nephropathy, sepsis, neoplasia); venous/pulmonary thromboembolism management. This monograph lists 3 reference doses for dogs, cats and horses, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/enoxaparin · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Lovenox, Clexane, LMWH
- **Species with doses:** Dogs, Cats and Horses
- **General dose range:** 1–1.5 mg/kg SC q6–12h (SC) — check the species tables for the indication
- **Routes:** SC
- **Last reviewed:** 1 October 2026

## Indications

- Feline arterial thromboembolism (ATE) — treatment/prophylaxis in cardiomyopathy
- Thromboprophylaxis in hypercoagulable disease (IMHA, protein-losing nephropathy, sepsis, neoplasia)
- Venous/pulmonary thromboembolism management

## Enoxaparin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Enoxaparin doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Thromboprophylaxis (IMHA/PLN/hypercoagulable) | 0.8–1 mg/kg | SC | q6–8h | — |

- Thromboprophylaxis (IMHA/PLN/hypercoagulable): Papich 5e and Plumb’s p.462 (Lunsford): 0.8 mg/kg SC q6h maintains therapeutic anti-Xa in normal dogs; 0.8–1 mg/kg SC q6–8h (Alwood). Adjust to anti-Xa where available.

### Cats

*Enoxaparin doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Arterial thromboembolism (prophylaxis/treatment) | 0.75–1.25 mg/kg | SC | q6–12h (q6h preferred) | — |

- Arterial thromboembolism (prophylaxis/treatment): Papich 5e: 0.75–1 mg/kg SC q12h, up to 1.25 mg/kg SC q6h (q6h preferred by many). Plumb’s p.462: 1 mg/kg SC q12h gives a measurable antithrombotic effect (Van De Wiele); cats clear LMWH quickly — 1.25 mg/kg SC q6h is the current recommendation (Alwood). Titrate to anti-Xa 0.5–1 IU/mL where available.

### Horses

*Enoxaparin doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Thromboprophylaxis | 0.5–1 mg/kg | SC | q24h | — |

- Thromboprophylaxis: Papich 5e: prophylaxis 0.5 mg/kg SC q24h; 1 mg/kg q24h for high-risk patients. Plumb’s p.462: no published recommendation, but once-daily SC dosing appears useful (Schwarzwald 2002).

## Contraindications

Active uncontrolled haemorrhage, severe thrombocytopenia, and recent surgery/trauma with bleeding risk. Significant renal impairment (LMWH accumulation → bleeding). Known heparin/LMWH hypersensitivity (or history of heparin-induced thrombocytopenia in people). Concurrent other anticoagulants unless intended. Neuraxial procedures (bleeding).

## Species-specific warnings

> **Caution:** Cats: Cats clear LMWH rapidly — q12h dosing is often inadequate; frequent (q6–8h) dosing or anti-Xa-guided dosing is needed. Combine with clopidogrel for long-term ATE prevention.

## Adverse effects

- Haemorrhage (the principal risk) — dose-related
- Injection-site bruising/haematoma
- Thrombocytopenia (uncommon)
- Short duration → frequent dosing needed (a practical limitation)

## Drug interactions

- Other anticoagulants/antiplatelets (clopidogrel, aspirin, warfarin, NSAIDs): additive bleeding risk (clopidogrel often combined deliberately in feline ATE)
- Protamine: only PARTIAL reversal of LMWH
- Drugs reducing antithrombin: reduced efficacy

## Pregnancy and lactation

Does not cross the placenta — LMWH is the preferred anticoagulant when anticoagulation is needed in pregnancy.

## Monitoring

- Anti-Factor-Xa activity (peak ~0.5–1 IU/mL) where available — the appropriate LMWH monitor (NOT aPTT)
- Bleeding signs / PCV; platelet count
- Renal function (accumulation/bleeding risk)
- In feline ATE: transition/combination with clopidogrel for long-term prevention

## Toxicity and overdose

The dose-limiting toxicity is HAEMORRHAGE, increased by renal impairment (accumulation) and concurrent antithrombotics. Bleeding can occur at any site; overdose prolongs anti-Xa activity. Heparin-induced thrombocytopenia is rare in animals. Protamine only partially reverses it, so over-anticoagulation is harder to neutralise than with unfractionated heparin.

Management: Stop the drug. PROTAMINE provides only PARTIAL reversal of LMWH (≈1 mg protamine per 1 mg enoxaparin given in the last few hours; give slowly). For significant bleeding, supportive care with fresh frozen plasma/transfusion as needed; monitor anti-Xa where available. Reduce dose/extend interval in renal impairment.

## Clinical pearls

- A more predictable, anti-Xa-targeted heparin — but in cats and dogs its SHORT half-life means FREQUENT dosing (often q6–8h in cats), unlike the once/twice-daily human regimen
- Monitor with ANTI-Xa activity, not aPTT (LMWH has little effect on aPTT)
- Protamine only PARTIALLY reverses it — over-anticoagulation is harder to neutralise than with unfractionated heparin; reduce dose in renal impairment
- For feline arterial thromboembolism, it is commonly used acutely and combined with/transitioned to clopidogrel for ongoing prevention

## Mechanism of action

A depolymerised (low-molecular-weight) fraction of heparin that binds antithrombin and PREFERENTIALLY accelerates inactivation of factor Xa (with relatively less anti-thrombin/IIa activity than unfractionated heparin) — inhibiting clot propagation. The higher, more consistent anti-Xa:anti-IIa ratio gives a more predictable dose-response (less monitoring) and longer human half-life — though in cats and dogs clearance is rapid, necessitating more frequent dosing than in people.

## Formulations and products

- Pre-filled syringe 100 mg/mL (40/60/80 mg)
- Clexane — 40 / 60 / 80 mg pre-filled syringe (100 mg/mL), SC injection (human-label)
- Lovenox / generic enoxaparin — 40 / 60 mg syringe, SC injection (human-label)

## Storage

Pre-filled syringes: 15–25 °C, do not freeze; protect from light.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Enoxaparin for dogs?

Reference doses for Enoxaparin in dogs: 0.8–1 mg/kg SC q6–8h (Thromboprophylaxis (IMHA/PLN/hypercoagulable)). Confirm against the label and the patient before use.

### What is the dose of Enoxaparin for cats?

Reference doses for Enoxaparin in cats: 0.75–1.25 mg/kg SC q6–12h (q6h preferred) (Arterial thromboembolism (prophylaxis/treatment)). Confirm against the label and the patient before use.

### What is the dose of Enoxaparin for horses?

Reference doses for Enoxaparin in horses: 0.5–1 mg/kg SC q24h (Thromboprophylaxis). Confirm against the label and the patient before use.

### When should Enoxaparin not be used?

Active uncontrolled haemorrhage, severe thrombocytopenia, and recent surgery/trauma with bleeding risk. Significant renal impairment (LMWH accumulation → bleeding). Known heparin/LMWH hypersensitivity (or history of heparin-induced thrombocytopenia in people). Concurrent other anticoagulants unless intended. Neuraxial procedures (bleeding).

### What are the side effects of Enoxaparin in animals?

Haemorrhage (the principal risk) — dose-related; Injection-site bruising/haematoma; Thrombocytopenia (uncommon); Short duration → frequent dosing needed (a practical limitation).

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.