"The state fought the case robustly, calling my client a liar and contradicting my client's evidence at every possible opportunity," Mr. Murray said in a telephone interview from his office in Ireland on Monday. "But, at the end of the plaintiff's case," he said, "the state buckled and settled the case, paid him compensation and paid all his costs."

In this country, the federal government and HoffmanLaRoche, mefloquine's developer, will be in a court in North Bay, Ont., on Friday to argue that a class-action suit brought by soldiers who took part in the Somalia mission of the early 1990s should not proceed because too much time has passed since the suit was launched in 2001.

The soldiers were forced to take the drug as part of a poorly monitored and possibly illegal clinical trial. Ronald Smith, the lead plaintiff in the Canadian case, says the drug left him with a host of residual mental-health issues including depression, aggressive behaviour, poor concentration, social isolation and suicidal thoughts.

Mr. Smith's suit sat dormant for 17 years as his lawyers debated who would take it to court. It was reactivated as evidence around the world began to link mefloquine to the types of symptoms experienced by Canadian soldiers in Somalia.

His statement of claim says the military required the soldiers to take the drug, but ignored the rules of the clinical trial, which said they must be watched for adverse reactions and treated for any side effects in a timely manner, among other things.

That was also the crux of the case launched by Mr. Cole in Ireland. Mr. Cole's suit related to the effects of mefloquine and the manner in which it was "administered to him and the manner in which it was screened and monitored," Mr. Murray said.

The Irish government conceded no liability but Mr. Murray says future cases should be much easier to fight because the testimony is on record. There are about 57 other Irish soldiers who have also launched suits related to mefloquine.

 

Health Canada updated the warning labels for the drug in 2016 to emphasize that certain side effects can persist for months or years after the drug is discontinued, and some may be permanent in some patients.

The Canadian military conducted a review of the medical literature this year and concluded there is no evidence that the drug causes long-lasting problems. But it now says alternative drugs are the preferred options for soldiers who deploy to countries where malaria is a risk.

Remington Nevin, a doctor at the Johns Hopkins University Bloomberg School of Public Health in Maryland, who has studied the drug's effects for nearly a decade, testified on behalf of Mr. Cole and expects to be called as a witness in the Canadian case, if it goes ahead.

"The Canadian government itself has taken until 2017 to conclude that there were problems with the drug significant enough to warrant it being made a drug of last resort," Dr. Nevin said. "So, if it took the Canadian government until 2017 to recognize this," he said, "it's not surprising that these issues have not made it to court until now."

Cathay Wagantall, the Conservative deputy critic for veterans affairs, said she is disappointed that the government is trying to stop the class-action suit by using the procedural argument that too much time has elapsed.

"This government is apologizing for numerous things and, at the same time, will not apologize for what happened in Somalia or at least take the steps to reopen the case and look at it truthfully," she said, "because these veterans know what they suffered and there's proof out there."