Heparins, low-molecular-weight

Hirsh J, Warkentin TE, Shaughnessy SG et al (2001) Heparin and low-molecular-weight heparin mechanisms of action, pharmacokinetics, dosing, monitoring, efficacy, and safety. Chest 119(Suppl.) 64S-94S... 

Fractionated Heparins Low-Molecular- Weight Heparins (IMWHs) ... 

Polysaccharides can regulate weak interactions between protein molecules. A recent example is the effect of low molecular weight heparin molecules on the weak dimerisation of the plasminogen growth factor NKl, or at least a mutant thereof [135]. 

The multiple effects of UFH on the coagulation cascade may increase its potential to cause hemorrhage." Anticoagulants with more specific sites of action may confer a better safety profile. Two such anticoagulants are low-molecular-weight heparin (LMWH) and heparinoids. 

FIGURE 7.2 LMWH inhibits factor Xa and minimally affects factor Ha thus, activated partial thromboplastin time is not used to measure its anticoagulant activity. (Reprinted from the American Family Physician published by the American Academy of Family Physicians, February 15th, 1999, in an article entitled Low-molecular-weight heparin in outpatient treatment of DVT. )... 

For patients with Acute Ischemic Stroke they recommend clinicians not to use full-dose anticoagulation with IV, subcutaneous, or low-molecular-weight heparins or heparinoids (grade 2B evidence). 

There is no recommendation for general use of heparin, low-molecular-weight heparin, or heparinoids after ischemic stroke (Level of Evidence I). 

Administration of low-dose heparin or low-molecular-weight heparin in an equivalent dose is always recommended in bedridden patients to reduce the risk of DVT and PE (Level of Evidence II). 

Gordon DL, Linhardt R, Adams HP. Low molecular-weight heparins and heparinoids and their use in acute or progressing ischemic stroke. Clin Neuropharmacol 1990 13 522-543. 

Bath P, Iddenden R, Bath F. Low-molecular-weight heparins and heparinoids in acute ischemic stroke, a meta-analysis of randomised controlled trials. Stroke 2000 31 1770-1778. 

Berge E, Abdelnoor M, Nakstad PH, Sandset PM, on behalf of the Haest Study Group. Low molecular-weight heparin versus aspirin in patients with acute ischemic stroke and atrial fibrillation a double blind randomised study. Lancet 2000 335 1205-1210. 

Sandercock P, Counsell C, Stobbs SL. Low-molecular-weight heparins or Heparinoids versus standard Unfractionated heparin for acute ischemic stroke (Review). The Cochrane Collaboration 2006. 

Low molecular weight heparins (adjust dose for renal dysfunction [i.e., creatinine clearance <30 mL/min])... 

All patients with a mechanical prosthetic heart valve should receive concomitant unfractionated heparin or a low molecular weight heparin in combination with warfarin pharmacotherapy until the INR is therapeutic and stable for two consecutive days... 

Low molecular weight heparins (adjust doses for renal dysfunction)... 

Patients with cancer who develop a venous thromboembolism may benefit from long-term therapy with a low molecular weight heparin (at least the first 3-6 mo of pharmacotherapy) instead of oral warfarin... 

Abciximab, aminophylline, amiodarone, amrinone, aspirin, carbamazepine, chlorpromazine, danazol, diltiazem, eptifi-batide, heparin, histamine2-receptor antagonists, low molecular weight heparins, methyldopa, milrinone, procainamide, quinidine, quinine, NSAIDs, thiazide diuretics, ticlopidine, tirofiban, and valproic acid... 

Discontinue all heparin and low molecular weight heparin sources o Intravenous, subcutaneous, flushes, and heparin-coated catheters... 

Avoid low molecular weight heparins (high cross-reactivity)... 

Low-molecular-weight heparins Bleeding, heparin-induced thrombocytopenia Clinical signs of bleeding3 baseline CBC and platelet count daily CBC, platelet count every 2 days (minimum, preferably every day) SCr daily... 

State at least two potential advantages of the low-molecular-weight heparins and fondaparinux over unfractionated heparin. 

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