Heparins and heparinoids

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. 

Low-molecular-weight heparins and heparinoids are not recommended in the treatment of acute ischemic stroke.11 A meta-analysis was performed using data from 10 randomized controlled trials.19 A non-significant decrease in combined death and disability and a non-significant increase in case fatality and hemorrhage were seen. A reduction in venous thromboembolic events was observed in acute stroke patients however, there was also an increase in extracranial bleeding. 

The use of full-dose unff actionated heparin in the acute stroke period has not been proven to positively affect stroke outcome, and it significantly increases the risk of intracerebral hemorrhage. Trials of low-molecular-weight heparins and heparinoids have been largely negative and do not support their routine use in stroke patients. 

DL Gordan, RJ Linhardt, HP Adams. Low-molecular-weight heparin and heparinoids in cerebrovascular disease. Clin Neuropharmacol 13 522-543, 1990. 

Use of heparin and heparinoids is aimed at inhibiting thrombus propagation into large and small vessels and prevent arterial (and venous) re-embolisation. Very few clinicians use this approach, at least for the time being. 

Kikta MJ, Keller MR Humphrey PV, et al. Can low molecular weight heparins and heparinoids be safely given to patients with heparin-induced thrombocytopenia syndrome Surgery 1993 114 705-710. 

Heparins and heparinoids constitute a group of compounds which have been shown in the past two decades to have many remarkable pharmacological properties. Their potency as pharmacological agents is usually overlooked because they do not cause the dramatic crises of classical pharmacology— respiratory and cardiovascular collapse. In fact, many of their pharmacological effects appear to be favourable to the physiologic economy. 

Mucopolysaccharides are naturally occurring carbohydrate polymers usually containing glucosamine and a uronic acid. They share, to some degree, the properties listed for heparin and heparinoids. They contain less sulphur, are much weaker as metachromatic and anticoagulant substances, and differ in solubility characteristics. Their solutions show considerable viscosity. 

Heparin may be classified as a mucopolysaccharide on the basis that it contains glucosamine, but it has very distinctive properties, and it is better to recognize a separate class of natural compounds, the heparins or hepar-inoids. In this review, the term mucopolysaccharide is limited to the substances in Table 3.1, as distinct from the heparins and heparinoids, listed in Table 3.2. Sulphation of mucopolysaccharides results in heparinoids when the product resembles heparins in the chemical and biological properties included under definitions. An important biological difference is that the typical mucopolysaccharides, such as the chondroitin sulphuric acids, are the important structural materials of connective tissue, while the naturally... 

Heparins and heparinoids are grouped in Table 3.2. Some are naturally occurring compounds, whilst others are derivatives prepared from heparins or from mucopolysaccharides. Semi-synthetic compounds have been prepared by degradation of natural polysaccharides followed by sulphation with chlorsulphonic acid or methyl sulphate . The common activities shown by the heparins and heparinoids—complexing with organic bases and proteins, antilipaemic activity and anticoagulant activity—are also shown by various sulphonic acid dyes and by polyphosphates. The table is completed with a list of those preparations that have been issued to provide depot preparations of heparins and heparinoids. 

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