Surgeons in Canada have reported that a man undergoing surgery developed greenish black blood after taking migraine medication.

BBC News reports that the 42-year-old man was undergoing surgery on his leg and surgeons discovered the colour of his blood had changed when they made an incision. The patient had been taking a daily dose of 200mg of migraine medication sumatriptan – which had resulted in a rare condition called sulfhaemoglobinaemia. This involves sulphur being introduced into oxygen-carrying haemoglobin in red blood cells.

The patient was undergoing surgery to release pressure in his limbs after having fallen asleep in a sitting position and developed the dangerous condition compartment syndrome.

Surgeons were performing urgent fasciotomies – ‘limb-saving procedures’ that involve surgical incisions to relieve pressure and swelling – when they discovered the green-black colour of his blood.

In compartment syndrome, swelling and pressure in limbs confined to a restricted space results in impaired blood flow and can cause localised damage to tissue and nerves.

Compartment syndrome is usually caused by trauma, internal bleeding or a wound dressing or plaster cast being applied too tightly.

The lead doctor working on the case – Dr Alana Flexman from St Paul's Hospital in  

Vancouver – told The Lancet journal:

‘The patient recovered uneventfully – and stopped taking sumatriptan after discharge. When seen five weeks after his last dose, he was found to have no sulfhaemoglobin in his blood.’

Doctors managed to save the man’s leg after the surgery.

Green-black blood colour is associated with Star Trek’s resident Vulcan Dr Spock, who had copper rather than iron in his blood, unlike human beings.

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