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Low molecular weight heparin for intravenous drug users with deep vein thrombosis
  1. Michael Russell, Medical Student,
  2. Deborah Dawson, Clinical Research Nurse
  1. Department of Emergency Medicine, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK;


    A short cut review was carried out to establish whether low molecular weight heparins were safer and more effective anticoagulants than coumarins in injecting drug users (IDUs) with deep venous thrombosis (DVT). Altogether 276 papers were found using the reported search, of which two presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.

    • BETs
    • deep vein thrombosis
    • injecting drug user

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    Report by Michael Russell,Medical StudentChecked by Deborah Dawson, Clinical Research Nurse

    Clinical scenario

    A 26 year old IDU with proximal DVT caused by injecting into the groin is showing poor control of their INR (and poor compliance with blood testing) while being prescribed standard warfarin. You wonder if the patient would be better managed using subcutaneous injections of low molecular weight heparin (LMWH) to take away the need for monitoring.

    Three part question

    In [IV drug users with DVT] are [low molecular weight heparins better than coumarins] at [safe and effective anticoagulation]?

    Search strategy

    Medline 1966-07/04 and Journals@OVID using the OVID interface. [exp Substance abuse, intravenous OR intravenous drug use$.mp OR exp Substance-Related disorders OR exp Injections, intravenous OR drug OR exp Heroin Dependence OR exp Heroin OR OR illicit drug$.mp OR exp street drugs OR injecting drug use$.mp OR drug depend$.mp OR drug] AND [exp deep vein thrombosis OR deep vein thromb$.mp OR deep venous throm$.mp OR] AND [exp Heparin OR OR exp Heparin, Low molecular weight OR low molecular weight OR fractionated OR OR OR OR OR OR OR OR OR exp warfarin OR OR exp coumarins OR] Limit to human AND English language.

    Search outcome

    Altogether 276 papers were identified of which 274 were irrelevant or insufficient quality for inclusion. The remaining two papers are shown in table 2.

    Table 2


    There is evidence that LMWHs are a safe and effective treatment for DVT. The drug is a recognised alternative to warfarin in certain patient groups such as pregnant women. Supervision of the INR with warfarin allows clinicians to monitor the effectiveness of the anticoagulant. With LMWHs there is no way of knowing if the patient is taking the drug, and as IDUs are traditionally seen as a chaotic patient group, then this would be a concern. There are no RCTs comparing LMWHs with coumarins in the management of intravenous drug users. Thus there is currently very limited evidence on the best ways to manage this patient group.


    Low molecular weight heparin seems to be a safe method of anticoagulation and may be considered as an alternative to warfarin in the anticoagulation of IDUs because it does not require ongoing monitoring. However, the evidence is very limited. Local guidelines should be followed.

    Report by Michael Russell,Medical StudentChecked by Deborah Dawson, Clinical Research Nurse