What is Low Molecular Weight Heparin?

If you’re interested in heparin therapy, you’ve probably wondered what the difference is between low and high-molecular-weight heparin. There are several key differences between the two types. Let’s take a closer look. In addition to comparing the two forms, you should know about their contraindications and pharmacokinetics. Below, we’ll explain the key differences.

High-molecular-weight heparin

LMWH and HMWH are similar in their molecular structure and anticoagulant properties. They both inhibit the coagulation factors factor Xa and thrombin. The primary differences between HMWH and LMWH are the chain lengths and reduced charges. LMWH has a slightly higher dissociation constant than HMWH. This makes it less effective in reducing blood clots and promoting healing in wounds.

In vitro studies of the anticoagulant activity of high-molecular-weight heparn fractions have shown similar results. The HMW fraction was two-times more effective than the LMW fraction in APTT assays, and the low-molecular-weight heparin was half as effective in the anticoagulant assays using synthetic substrate S-222.

While LMWH is slightly less potent, it is still a useful anticoagulant. LMWH is more readily absorbed than UFH, and is less likely to cause resistance. Furthermore, LMWH is also more consistent in its anticoagulant activity and clearance. LMWH is available as a one-time or twice-daily dose, with no need for coagulation monitoring.


Thrombocytopenia due to low-molecular-weight heparin is less common than heparin-induced thrombocytopenia. Although the causes of heparin-induced thrombocytopenia are not fully understood, the following review will discuss the similarities and differences between these conditions. It will also outline the role of heparin in the development of thrombocytopenia.

Although studies comparing LMWH to UFH have not shown a difference in thrombocytopenia rates, this may be because the study periods have been too short. In a study comparing LMWH with UFH, patients with HIT developed significant levels of Heparin-PF4 antibodies at days 3-5 and 7-10 postoperatively, respectively. In the same study, patients were analyzed based on their LMWH use and whether they were taking prophylactic or therapeutic doses of LMWH or heparin.

In a case report of a 57-year-old woman, who had been hospitalized in a psychiatric ward for four months, we report a case of thrombocytopenia due to LMWH. This patient had arterial hypotension, severe dehydration, anorexia, and self-induced vomiting. She had no previous history of LMWH use. Moreover, her platelet count was only 490 G/L.


The pharmacokinetics of low-molecular-weight heparin (LMWH) is the study of the distribution and the elimination of the antithrombotic drug. The main differences between LMWH and UFH are in their manufacturing processes and in vitro potency. Both have antithrombotic and anticoagulant properties. The following sections discuss their pharmacokinetics and toxicity.

The elimination of heparin depends on its molecular weight and dose. In healthy subjects, the drug is cleared from the blood by a saturable mechanism. In the case of low-molecular-weight heparin, the non-saturable pathway accounts for its elimination. In patients with chronic renal insufficiency, however, the elimination of LMWH is non-saturable.

Unfractionated heparin is composed of molecules with different molecular weights, which may contribute to the variable response observed in patients. In addition, LMWHs exhibit nonlinear pharmacokinetics, with a rapid initial disappearance phase and a convex disappearance curve. These differences in the disappearance rate of low-molecular-weight heparin have implications for the safety of these products.


While the use of heparins is common, the risks associated with their inappropriate use are substantial. Safer prescribing requires careful consideration of precautions, contraindications, and dosage. When appropriate, heparins should be prescribed for specific patient populations. Moreover, the appropriate dosage depends on the type of anesthesia and surgery. Below, you’ll learn about the contraindications and dosage for different types of heparins.

Low-molecular-weight heparin is an effective anticoagulant for the prevention of deep vein thrombosis (DVT), especially in patients who have undergone major surgery. While it has a high risk of adverse effects, it can be administered by self-administered medication or with a family member or visiting nurse. In addition to its safety, low-molecular-weight heparin is easy to use and very affordable.

In addition to anticoagulant properties, low-molecular-weight heparin can accumulate in the blood, which can result in a potentially dangerous accumulation of anticoagulant effects. Therefore, patients with low creatinine clearance should be excluded from low-molecular-weight heparin and be monitored regularly to determine whether the anti-factor Xa level has increased. This study aimed to determine the appropriateness of low-molecular-weight heparin treatment and the contraindications to its use. The literature was searched for prospective studies that compared the pharmacokinetics of LMW heparin with that of other heparins. Additionally, reference lists were reviewed to identify additional articles that may be relevant to the topic.

Leave a Reply

Your email address will not be published.