Low molecular weight heparin: Difference between revisions
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==Background== | ==Background== | ||
A class of anticoagulant medications. These drugs are used for treating deep vein thrombosis, pulmonary embolism when it is located in the veins, or heart attacks and strokes when located in the arteries. LMWHs cannot be acceptably measured using the partial thromboplastin time (PTT) or activated clotting time (ACT) tests. Rather, LMWH therapy is monitored by the anti-factor Xa assay, measuring anti-factor Xa activity. | A class of anticoagulant medications. These drugs are used for treating deep vein thrombosis, pulmonary embolism when it is located in the veins, or heart attacks and strokes when located in the arteries. LMWHs cannot be acceptably measured using the partial thromboplastin time (PTT) or activated clotting time (ACT) tests. Rather, LMWH therapy is monitored by the anti-factor Xa assay, measuring anti-factor Xa activity. | ||
LMWHs are defined as heparin salts having an average molecular weight of less than 8000 Dalton. LMWHs inhibit the coagulation process through binding to antithrombin which in turn inhibition activated factor X.<ref>Garcia DA, Baglin TP, Weitz JI, et al. (2012). "Parenteral anticoagulants: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines"</ref> | |||
==Types== | ==Types== | ||
Revision as of 14:29, 17 March 2015
Background
A class of anticoagulant medications. These drugs are used for treating deep vein thrombosis, pulmonary embolism when it is located in the veins, or heart attacks and strokes when located in the arteries. LMWHs cannot be acceptably measured using the partial thromboplastin time (PTT) or activated clotting time (ACT) tests. Rather, LMWH therapy is monitored by the anti-factor Xa assay, measuring anti-factor Xa activity.
LMWHs are defined as heparin salts having an average molecular weight of less than 8000 Dalton. LMWHs inhibit the coagulation process through binding to antithrombin which in turn inhibition activated factor X.[1]
Types
| LMWH | Average molecular weight | Ratio anti-Xa/anti-IIa activity |
|---|---|---|
| Bemiparin | 3600 | 8.0 |
| Nadroparin | 4300 | 3.3 |
| Reviparin | 4400 | 4.2 |
| Enoxaparin (Lovenox) | 4500 | 3.9 |
| Parnaparin | 5000 | 2.3 |
| Certoparin | 5400 | 2.4 |
| Dalteparin | 5000 | 2.5 |
| Tinzaparin | 6500 | 1.6 |
Differences from unfractionated heparin
Differences from heparin (i.e. "unfractionated heparin") include:
- Average molecular weight: heparin is about 15 kDa and LMWH is about 4.5 kDa.[2]
- Less frequent subcutaneous dosing than for heparin for postoperative prophylaxis of venous thromboembolism.
- Once or twice daily subcutaneous injection for treatment of venous thromboembolism and in unstable angina instead of intravenous infusion of high dose heparin.
- No need for monitoring of the APTT coagulation parameter as required for high dose heparin.[3]
- Possibly a smaller risk of bleeding.
- Smaller risk of osteoporosis in long-term use.
- Smaller risk of heparin-induced thrombocytopenia, a potential side effect of heparin.
- The anticoagulant effects of heparin are typically reversible with protamine sulfate, while protamine's effect on LMWH is limited.
- Has less of an effect on thrombin compared to heparin, but about the same effect on Factor Xa.
Indications
See Also
Source
- ↑ Garcia DA, Baglin TP, Weitz JI, et al. (2012). "Parenteral anticoagulants: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines"
- ↑ Michael D Randall; Karen E Neil (2004). Disease management. 2nd ed. London: Pharmaceutical Press. 186.
- ↑ http://chestjournal.chestpubs.org/content/119/1_suppl/64S.full