Increasingly, physicians in emergency departments are seeing cases of injecting drug users (IDU) with dangerously high International Normalized Ratio (INR) results. Some of these patients have admitted to buying warfarin from a “street” source and taking the medication without INR monitoring. This group are known to be at significant risk of developing venous thrombo‐embolic disease1 and have difficulties in accessing healthcare.2
The risk factor of femoral vein injecting and recognition of progressive symptoms of deep vein thrombosis (DVT) is common. Many IDU are also aware of treatment with warfarin, and, hence, self‐diagnose and treat using street acquired warfarin.
Complications associated with warfarin treatment include major haemorrhage. Also, a sub‐therapeutic INR does not protect against thrombus propagation and pulmonary embolism.
A 37‐year‐old man with a long history of injecting drug use, was admitted with extensive bilateral DVT, multiple septic pulmonary emboli and pneumonia with a para‐pneumonic effusion. During admission a temporary, indwelling inferior vena cava filter was inserted.
The patient failed to attend follow‐up, although he continued to take warfarin, purchasing it from a fellow IDU who obtained the drug on prescription. When the patient's INR was checked 2 months later, it was >10.
This patient bought warfarin from a street source. He self‐administered the anticoagulant in an attempt to treat and prevent worsening symptoms. We are aware of a number of other people presenting with bleeding symptoms to accident and emergency. These people indicate a willingness to have the correct treatment, however, an inability to access healthcare. Improved education and provision of healthcare facilities aimed at this group are recommended to prevent complications associated with treatment of venous thrombo‐embolism. This letter illustrates the need for clinicians who treat IDU to be aware of unexplained haemorrhagic complaints, which may be due to the use of street acquired warfarin.
References
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