In clinical anticoagulation therapy, low molecular weight heparins (LMWHs) are almost ubiquitous. They are widely used in various clinical scenarioses, including the prevention and treatment of venous thromboembolism, perioperative anticoagulation, acute coronary syndromes, and hemodialysis.

However, an easily overlooked fact is that LMWHs are not "class-equivalent" drugs; there are differences in their use, dosage, and indications. Improper use may compromise efficacy and increase the risk of bleeding.

Recently, the Chinese Expert Consensus on the Clinical Application of Low Molecular Weight Heparins (hereinafter referred to as "the Consensus"), developed by the Precision Pharmacy Working Committee of the Chinese Association of Pharmacists, was published online. The Consensus systematically addresses five aspects: pharmaceutical characteristics, clinical applications, management of major adverse reactions, drug interactions, and pharmaceutical care of LMWHs. It aims to provide comprehensive guidance for clinicians, pharmacists, and related professionals to promote the standardized use of LMWHs, ensure patient medication safety, and improve patient outcomes.

This column focuses on several key questions:

• What differences among LMWHs should not be overlooked?
• Which specific uses for thrombosis prevention and treatment have clear consensus support?
• What should be noted when using LMWHs in special populations such as pregnancy, cancer, and the elderly?

Not All LMWHs Can Be Used Interchangeably

In everyday language, "low molecular weight heparin" is often used as a general concept. However, the Consensus clearly states that different LMWHs differ in molecular structure, molecular weight, and biological activity, which generally means they cannot be fully substituted for one another.

Taking pharmacokinetics as an example: the absorption and bioavailability of different LMWHs in vivo are not completely consistent. For instance:

• The subcutaneous bioavailability of enoxaparin and nadroparin is close to 100%;
• The subcutaneous bioavailability of dalteparin and bemiparin exceeds 90%;
• Although the pharmacokinetic profiles of other low molecular weight heparin sodium and low molecular weight heparin calcium preparations differ slightly, their subcutaneous bioavailability also remains between 90% and 100%.

Therefore, the choice of LMWH should be based on the specific indication and product label, with dosing according to the recommended dose for that indication. Simple dose conversion or empirical substitution among different LMWHs is not permitted.

What Are the Main Clinical Applications of LMWHs?

The Consensus systematically outlines the major areas in which LMWHs are currently approved and widely used in China, including:

• Prevention and treatment of venous thromboembolism (VTE), such as deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE)
• Perioperative thrombosis prevention, especially in high-risk surgeries such as orthopedics and oncology
• Anticoagulation therapy for acute coronary syndrome (ACS)
• Prevention of blood clot formation during hemodialysis

It is important to note that among the various LMWHs marketed in China, enoxaparin has the broadest indications, covering VTE prevention and treatment, ACS treatment, and hemodialysis. However, a broader range of indications does not simply mean that it is "better" or "stronger" in all clinical scenarioses; the choice of drug should still be based on approved indications and the patient's specific condition.

VTE Prevention: Risk Assessment is More Important Than "Blind Medication"

The Consensus emphasizes that VTE prevention is not about "starting medication immediately," but rather a decision-making process based on risk stratification. Clinicians should provide preventive measures according to guidelines, including basic prevention, mechanical prevention, pharmacological prevention, and combined prevention.

In clinical practice, physicians need to assess two factors simultaneously:

• Risk of thrombosis
• Risk of bleeding

Common VTE risk assessment scales include:

• Caprini Risk Assessment Model (for surgical patients)
• Padua Risk Assessment Model (for hospitalized medical patients)
• Khorana Risk Score (for cancer patients)

Pharmacological prophylaxis is an important intervention for high-risk VTE patients. The use of any VTE prophylactic agent carries a risk of bleeding, and bleeding risk assessment should accompany the entire thromboprophylaxis process. The IMPROVE bleeding score is commonly used for bleeding risk assessment in hospitalized medical patients.

For VTE prevention, LMWHs are recommended as first-line anticoagulants by multiple domestic and international guidelines and consensus statements, with a clear role particularly in orthopedic surgery and medical VTE prevention.

Treatment Phase: LMWH Remains an Important "Cornerstone Drug"

For VTE treatment, the expert consensus proposes a relatively consistent approach:

• For acute DVT patients without cancer: LMWH may be used first for anticoagulation, followed by a switch to a direct oral anticoagulant or warfarin based on the patient's condition, with treatment lasting at least 3 months.
• For DVT patients with cancer: LMWH or direct oral anticoagulants (for patients without gastrointestinal cancer) are recommended, with treatment lasting at least 3 months.
• For patients with acute low-to-intermediate risk PTE: LMWH is recommended as the initial anticoagulation regimen.

In Chinese clinical practice, currently only enoxaparin has the indication for treating PTE, which requires special attention when selecting a drug.

Medication in Special Populations: No "One-Size-Fits-All"

The expert consensus provides more specific principles for several special populations:

• Elderly patients
  The risk of bleeding is relatively increased, so monitoring should be strengthened and dose reduction considered when necessary;
  For elderly cancer patients with VTE and no contraindications, LMWHs are recommended for both initial and long-term anticoagulation; for high-risk elderly trauma patients requiring pharmacological VTE prophylaxis, prophylactic-dose LMWHs are the preferred choice.
• Pregnant and breastfeeding women
  LMWHs are recommended as the anticoagulant for VTE prevention during pregnancy and the puerperium;
  For pregnant women at high risk of VTE without clear contraindications, prophylactic anticoagulation with LMWHs may be considered, with dose adjustment based on body weight.
• Pediatric patients
  LMWHs can be used to treat catheter-related thrombosis (central venous or umbilical venous), femoral artery, cerebral venous sinus, unilateral or bilateral renal vein thrombosis, and primary or secondary VTE in children;
  Enoxaparin has relatively sufficient evidence for dose adjustment in pediatric populations.
• Patients with high or low body weight
  For patients with excessively high or low body weight, the dose should be adjusted based on body weight, and efficacy and safety should be dynamically evalsuated in conjunction with monitoring results.

Management of Adverse Reactions: Early Recognition and Standardized Response are Key

Regarding safety, the Consensus highlights two types of situations:

• Bleeding
  For minor bleeding, symptoms generally resolve after drug discontinuation without special treatment;
  For major bleeding, anticoagulation should be stopped immediately, hemostatic intervention performed, and protamine used if rapid reversal is needed.
• Heparin-induced thrombocytopenia (HIT)
  Once diagnosed, all heparin-based anticoagulants should be discontinued immediately, and a non-heparin anticoagulant regimen should be initiated;
  For HIT patients with thrombosis, warfarin is not recommended; if warfarin is being used, it should be stopped and its effect reversed with intravenous vitamin K before switching to another non-heparin anticoagulant.

The clinical application of LMWHs spans multiple fields, including internal medicine, surgery, oncology, critical care, and obstetrics. Rational use of LMWHs is key to improving the efficacy of thromboembolic disease prevention and treatment, reducing adverse reactions, and decreasing the occurrence and recurrence of thrombotic events.

True "standardized use" is not just about memorizing doses or indications, but about understanding differences, following evidence, and adhering to individualized assessment.

Behind this invisible yet crucial line of defense in anticoagulation therapy, respect for standards and attention to detail are themselves the most solid protection for patients.

As a global leader in the heparin industry, Hepalink remains committed to following international therapeutic consensuses, providing high-quality products, professional insights, and timely information to serve the safety of patients worldwide.

Reference:

Precision Pharmacy Working Committee of Chinese Association of Pharmacists, Editorial Committee of the Chinese Expert Consensus on Clinical Application of Low Molecular Weight Heparins. Chinese Expert Consensus on Clinical Application of Low Molecular Weight Heparins [J/OL]. Chinese Journal of Modern Applied Pharmacy, 1-19 [2026-02-09].