The mother of a 15-month old boy with cystic fibrosis said she was "terrified" about her child's future over fears the NHS might not prescribe the drug Kaftrio due to its cost.
Suzanne Doherty, from Dunbartonshire, said she has been waiting for her son Leo to be eligible for the drug since he was diagnosed with the condition at just four weeks old.
Cystic fibrosis (CF) is a condition that causes sticky mucus to build up in the lungs and digestive system, meaning it can lead to a significantly shorter life expectancy for many sufferers.
Kaftrio, which can cost £100,000 a year, is licensed for children over the age of two but health bosses are consulting on whether it is too expensive to prescribe to new patients.
Ms Doherty told BBC Scotland's Good Morning Scotland programme that when Leo was diagnosed with CF they were comforted by the knowledge of a drug being available to him at the age of two.
However, the drug costs £8,346 for a packet of 56 tablets, meaning NHS treatment could amount to between £100,000 and £200,000 per year for each patient.
The National Institute for Clinical Excellence (NICE), which guides the NHS in England, and the Scottish Medicines Consortium (SMC) are consulting on the use of Kaftrio for future patients due to its cost.
They said existing patients would still get the treatment regardless of its decision.
Ms Doherty said Leo had enjoyed good health until now but he is currently in hospital with a suspected chest infection.
She said: "As a parent obviously I don’t want to see my son in distress for the next two weeks, I don’t want to see him being given oxygen, being given IV antibiotics.
"This is what cystic fibrosis does. It can floor them for weeks on end.
"For a lot of parents, obviously with children older than that, it can be several visits over the years into hospital and it’s always roughly a two-week stay at a time."
Ms Doherty argued long and frequent stays in hospital, including the cost of continuous testing and appointments, could be avoided with use of the drug.
High price tag
She said: "Parents like myself will need to take time off to look after them. That would then mean claiming benefits.
"There would just be a chain of money that we would then need to survive on, through the government, that would probably exceed £100,000 a year."
Ms Doherty said: "It might seem like a lot of money, but it means my son can grow old. It means he can grow up and get a career and contribute back to society.
"It comes with a very high price tag but my question to NICE and SMC is, is £100k not worth my child’s life? Is it not worth any human’s life?"
Ms Doherty said alternative treatments appeared to be less effective and had more side effects.
"The result if he doesn’t get it, and those people who don’t get it, they are then going to be living a life full of ill health." Ms Doherty said.
Two other drugs for cystic fibrosis, Symkevi and Orkambi, are also at risk of no longer being prescribed.
Children being treated for cystic fibrosis by the NHS are often moved onto Kaftrio when they reach the age of six.
The drug has now been classed as safe for children aged two or older but for those yet to start it, it is not known if they ever will.
NICE and SMC will hold a four-week consultation before deciding if the three drugs will continue to be offered to new patients.
A spokesperson for the Scottish Medicines Consortium said those on the treatments will continue to receive them "irrespective of the outcome" of the ongoing consultations.