MONTREAL - Quebec health officials are warning that cocaine cut with an anti-parasitic medication is hitting the streets in the province and can cause a severe adverse reaction in illicit drug users.

The pharmaceutical levamisole -- most commonly used by veterinarians to treat worm infestations-- has been cropping up in the U.S. and Canada as a common adulterant to cut cocaine for street level consumption.

Use of the anti-parasitic drug by humans can cause nausea, dizziness and diarrhoea and -- with repeated exposure -- can lead to a reduced white blood cell count and a suppressed immune system.

The dangerous mix can also cause high blood pressure and an irregular heartbeat.

Last November, U.S. health authorities launched a health alert about the dangers of the blend after finding some 70 per cent of cocaine tested by drug enforcement authorities in July 2009 was positive for levamisole.

In a Quebec study, the public health institute found the presence of levamisole in eight out of ten blood samples taken from known drug users.

Cases have also cropped up in Alberta, Ontario and British Columbia.

Levamisole is no longer available in Canada but is still sold in the U.S.