The health of a seven-year-old Nova Scotia girl is beginning to decline after she had to stop taking a breakthrough drug that treats her cystic fibrosis because her parents can't afford the medication.

Carys Nurse, of Middle Sackville, has a mutation of the deadly genetic disease that can be treated using Kalydeco. The problem is the pills cost $300,000 a year.

When Carys' mother, Stacey, was laid off from Fisheries and Oceans Canada due to budget cuts, she also lost her drug plan.

That plan had paid for 80 per cent of the cost of the drug over a seven month stretch, while the manufacturer, Vertex Pharmaceuticals Inc., covered the rest.

Without the drug plan, Stacey and her husband Paul can't afford Kalydeco. What pills they had have all run out — Carys took the final one last week.

"We've seen what it could do for her," Stacey Nurse said. "We'd like to keep her on it."

The Nurses have appealed to the provincial health department and to the drug company to cover Carys on compassionate grounds. No luck.

The drugs had helped Carys breathe deeply, put on weight and feel energetic.

"The blue pill, when I took it, my belly didn't hurt," she said.

Four days after she stopped taking the drug, her mother said Carys began suffering from cramps.

Kalydeco treats a rare form of cystic fibrosis. While it is typically covered in the United Kingdom and by Medicaid in the United States, it isn't in Canada.

Last week a Wilmot, N.S., man told CBC he can’t afford the drug, even though it could dramatically improve and extend his life.

Vertex has said the price of the drug reflects how well it works and the cost to develop it.

I think there's a lot of goodwill to be had for companies who actually do the ethical thing and try to make drugs more affordable to patient populations. - Matthew Herder, health law expert at Dalhousie University

But one local health law expert says some companies are jacking up prices for "orphan" drugs that treat a very small number of people.

"There's a real worry with that kind of approach, because you're going to alienate people in the process," said Matthew Herder, an assistant professor at Dalhousie University.

"I think there's a lot of goodwill to be had for companies who actually do the ethical thing and try to make drugs more affordable to patient populations."

A cystic fibrosis specialist at the IWK Health Centre says the cost troubles him. Dr. Dan Hughes said public coverage of the drug would swallow up the budget for all cystic fibrosis patients in the province.

"For one patient, for one year, is a third of the cost of our entire budget," he said. "So if you had three patients, there's the entire budget gone."