The Canadian Cancer Society is warning people not to self-medicate with the cheap, widely available drug known as DCA.

Dichloroacetate is a drug used to treat lactic acid buildup in children as well as people with diabetes and AIDS — conditions that differ from cancer.

The drug has shown promise as a cancer treatment in studies on rats but it has never been tested on human cancer patients.

Heather Logan, the director of cancer control policy at the society who trained as a nurse, has worked with people fighting to prolong their lives. Logan said she sympathizes with those who are buying the drug and mixing it at home as a last resort, but stresses there are serious safety concerns.

"The challenge is with this drug, we don't actually know whether this may hasten their death, and it may also seriously impact their quality of life for the months that they have remaining," Logan told CBC Newsworld on Thursday.

Potential for nerve damage

Peripheral neuropathy is a serious side-effect of DCA that causes damage to the nerves in the hands and feet.

The side-effect may also occur in chemotherapy, but doses are carefully checked and doctors watch for symptoms. 

People taking the drug at home may not be aware of DCA's side-effects, ignore the symptoms, and end up with permanent nerve damage, Logan said.

It is also unknown whether DCA's side-effects are accentuated by interacting with cancer drugs or herbal products.

For the same reasons, Health Canada also urges people with cancer not to take untested drugs.

The only way to find out whether a drug is a safe cancer treatment is to test it in clinical trials on humans.

Dr. Evangelos Michelakis, a professor of medicine at the University of Alberta in Edmonton, discovered the drug's anti-cancer potential in animals and is trying to expedite its testing on humans.

Michelakis told an Edmonton newspaper that he is distressed that people with cancer are self-medicating with a drug that could be harmful to them.