Two medicines that reduce the main cause of death for people with cystic fibrosis will not be made routinely available on the NHS in Scotland.

The Scottish Medicines Consortium (SMC) said it heard "powerful testimonies" from patients and medics about the "potential benefits" of the drugs but ruled them out over doubts on cost-effectiveness.

Cystic fibrosis is a debilitating life-shortening illness that creates a mucus build-up that causes chronic lung infections and progressive lung damage.

Orkambi is used to treat cystic fibrosis in patients aged two and older while Symkevi treats those aged 12 and up.

The SMC heard both are used to reduce hospital admissions.

The Cystic Fibrosis Trust previously said Orkambi could benefit more than 330 people in Scotland. While not a cure, it slows decline in lung function, which is the main cause of death for cystic fibrosis patients.

SMC chairman Dr Alan MacDonald said the consortium recognised the decisions would be "disappointing".

"We understand the profound impact that cystic fibrosis has on patients and their families and we are aware of the need for effective treatments that target the underlying cause," he said.

"Patient groups and clinicians gave powerful testimonies about the impact of the condition and the potential benefits of these medicines.

"As these are orphan medicines, our committee members were able to apply additional flexibility in their decision-making but there remained significant uncertainty around their overall health benefits in the long-term, in relation to their costs.

"In order to be able to accept these medicines the committee will need to be satisfied of their cost-effectiveness and we continue to work with the company to achieve that."

Health secretary Jeane Freeman said she understood the "great disappointment" that would be felt from the decisions.

She said: "Since the Government became aware of the SMC decision last month we have been working with the SMC, the manufacturer and with other interested parties to develop the principles of a solution that can make possible the widest availability of these medicines, wherever clinically appropriate.

"This work continues now, as a matter of urgency."

She said a "considerable number" of patients are accessing the medicines through the Scottish Government's system for individual access, adding: "The Government hopes that all parties continue to work together to achieve a positive outcome for all the children and adults with cystic fibrosis in Scotland."

Manufacturer Vertex said it hoped to reach a solution with the Scottish Government regarding broad access to the drugs for eligible patients over the coming weeks.

In the meantime, the company said it would continue to allow access on an individual basis based on clinical need, which currently applies to 65 patients across Scotland.

Cystic Fibrosis Trust chief executive David Ramsden said: "The SMC's advice will come as a shock to people with cystic fibrosis and their families in Scotland.

"While talk of further negotiation between Vertex Pharmaceuticals and the Scottish Government is positive, people living in Scotland need these life-saving drugs now.

"The tragic wait has to end and now is the time for the Scottish Government to remain committed and Vertex to do all they can to ensure that this chance does not slip away again."

Separately, the SMC approved four medicines for routine use on Scotland's NHS. Buprenorphine injections will now be routinely offered to treat narcotic addicts unsuitable for methadone treatment.

Patients with a type of blood cancer, those suffering from genetic disease disease transthyretin amyloidosis and psoriasis patients will benefit from the three remaining medicines.