The diabetes drug Invokana, recently adopted by Nova Scotia's pharmacare program, is now the subject of a national class-action lawsuit.

Court documents filed at the Ontario Superior Court of Justice allege the drug can cause kidney damage or death in some of those who take it.

"We believe that Invokana is a very risky drug for kidney failure, and that the medical profession and users of the drug should be alerted to the dangers and consider very carefully whether they continue on Invokana," said Tony Merchant, the Regina-based lawyer whose company, Merchant Law Group, is behind the lawsuit.

The class action has not been certified. Merchant said he expects that to happen in the next six to seven months.

None of the allegations have been proven in court. 

Under Nova Scotia law, the action must first be certified as a class action before it can proceed.

Invokana was created by the multinational drug company Janssen Inc., and was approved by Health Canada in May 2014.

The Nova Scotia government added Invokana to the province's pharmacare formulary on Sept. 1, the third province to do so after Ontario and Quebec.

Scarborough woman at centre of lawsuit

Invokana isn't the only diabetes drug before the Canadian courts.

Lawyers in Halifax argued Tuesday in Nova Scotia Supreme Court for the certification of a class action suit against the drug Avandia from GlaxoSmithKline. Avandia is an insulin sensitizer, a different class of drugs from Invokana.

Invokana promises to lower blood sugar in Type 2 diabetics when used with diet and exercise.

It's a member of a new class of drugs called SGLT2 inhibitors, which act on the kidneys, lowering blood sugar by excreting excess glucose in the urine.

The class action statement of claim centres on a Scarborough, Ont., woman named Rosalba Joudry.

It alleges Joudry used Invokana for eight months, but stopped when she saw an advertisement for another Invokana class-action lawsuit on American TV.

Court documents say further tests showed Joudry was experiencing kidney failure.

The lawsuit claims more than $1 billion in damages on behalf of Canadian patients who have been allegedly harmed by the drug, accusing the drugmaker Janssen Inc. of negligence in testing Invokana, and failing to warn doctors of serious possible side effects.

'I think it's safe'

Tony Merchant is also calling for the drug to be taken off the Canadian market. 

"Part of what we are presenting in court is that the company ought to pull Invokana, that the knowledge that they have from being in the real market of the dangers if Invokana, that they ought not to continue to market Invokana."

None of these allegations has been tested in court.

Dr. Debbie Knight is a diabetes specialist in Dartmouth with 35 years of experience. She also works as a consultant for Janssen.

Knight is confident Invokana does no harm to diabetics' kidneys, "We know that even if you use it in people it with reduced kidney function, it does no further harm to the kidneys," she said.

"I think it's safe, yes. If I didn't think it was safe, I don't think I'd use it in any of my patients."

'We continue to work with Health Canada'

The U.S. Food and Drug Administration issued a warning in May that SGLT2 inhibitors, such as Invokana, may increase a patient's risk of ketoacidosis, a dangerous condition of high acidity in the blood.

An increased risk of ketoacidosis also forms part of the Ontario class action claim. Health Canada started a safety review of SGLT2 inhibitors in June for the same reason.

A Health Canada spokesperson says a review can lead to changes to a drug's conditions for approval, or withdrawal of approval altogether.

Jennifer McCormack, spokeswoman for Janssen Inc., said in an email, "We continue to work with Health Canada in their class assessment of the potential risk of diabetic ketoacidosis (DKA) with SGLT2 inhibitor use.

"Invokana (canagliflozin) provides important benefits to patients with Type 2 diabetes and we remain confident in the overall safety profile of Invokana," she said.

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