OTTAWA - A constitutional challenge to the Trudeau government's restrictive law on assisted dying has been bolstered with the addition of a second plaintiff: a B.C. woman who suffers unbearable pain from a debilitating, incurable disease but can't get medical help to end her life because her death is not imminent.

Robyn Moro, a 68-year-old retired retail business owner, joins Julia Lamb in challenging the year-old law, which allows medically assisted dying only for individuals whose natural death is "reasonably foreseeable."

"What's the point of waiting until somebody's almost dead before you do anything about it?" Moro said in an interview.

"You might as well not have the law."

Moro suffers from Parkinson's disease, a degenerative disorder of the central nervous system. It has caused continual excruciating pain in her legs, acute nausea that has resulted in repeated hospitalization and tremors that shake her whole body.

Her condition is exacerbated by the fact that she's allergic to many of the medications normally prescribed for the disease and for pain relief.

"I can't imagine having any more pain than I have now and yet Parkinson's is a progressive disease," Moro said.

"It progresses and mine progresses pretty quickly and so, yes, it's terrifying to think that it will get worse and all I can take is a regular strength Tylenol."

Moro meets all the other eligibility criteria for an assisted death set out in the law: she is a consenting adult "in an advanced stage of irreversible decline" from a serious and incurable disease. But she's been denied her request for medical assistance in dying because she is not near death.

If the legal challenge fails or takes years to wend its way through the courts, Moro intends to end her life by refusing food and water - an agonizing end that can take up to two weeks before a person dies from dehydration.

"I've had enough," she said. "If that's the only way of ending my suffering then that's what I'll do."

And if she's forced to take that "terrifying" way out, she'd like to invite Prime Minister Justin Trudeau and Justice Minister Jody Wilson-Raybould, who crafted the assisted dying law, to witness her death.

"I think they should see the result of what they've done. It's fine to create a law and then walk away from it and not think about it too much," Moro said.

"But if they had to see people actually having to do themselves in, maybe it would shake them up a little bit."

The law was enacted last June in response to a landmark 2015 ruling by the Supreme Court of Canada, which struck down the prohibition on assisted dying as a violation of an individual's right to life, liberty and security of the person.

However, the law is much more restrictive than what the top court envisaged. The court directed that medical assistance in dying should be available to consenting, competent adults with "grievous and irremediable" medical conditions that are causing enduring suffering that they find intolerable.

There was no requirement that the condition be terminal or that a person be near death. Indeed, the court ruling specifically addressed individuals like Moro, who "may be condemned to a life of severe and intolerable suffering."

"A person facing this prospect has two options: she can take her own life prematurely, often by violent or dangerous means, or she can suffer until she dies from natural causes. The choice is cruel," the Supreme Court said.

The British Columbia Civil Liberties Association, which is spearheading the court challenge, contends that the law violates the charter by excluding individuals who could live for years with medical conditions, like Parkinson's, that cause intolerable suffering.

The BCCLA, which also spearheaded the original court challenge that led to the Supreme Court's ruling, launched the latest challenge within days of the law being enacted, with Julia Lamb as the sole plaintiff.

Lamb is a wheelchair-bound 26-year-old who suffers from spinal muscular atrophy, a degenerative disease that she fears will eventually consign her to years of unbearable suffering, unable to use her hands, breathe without a ventilator or eat without a feeding tube.

Her notice of civil claim says Lamb wants "the peace of mind" of knowing she can choose an assisted death should her condition become intolerable to her.

An affidavit has now been filed with the Supreme Court of B.C. to add Moro to the lawsuit.

"In the last three months, Robyn's pain has become unbearable to her," the affidavit says. "She cries from pain and frustration every day."

"Robyn finds her quality of life unacceptable. She feels that she is not living life but rather enduring it as a daily cruelty."

BCCLA counsel Jay Aubrey said the addition of Moro "strengthens the case because her situation highlights the urgency of this situation, as well as the awful position the legislation creates for people like Robyn."

No trial date has yet been set but the case is not expected to be heard until next year.