People with multiple sclerosis will have to pay up to €500 a month for a new drug that could help them walk, after the HSE confirmed Fampyra is not covered under any of its community drugs schemes.
Famprya or fampridine has been licensed in Ireland and became commercially available though pharmacies for the first time this year.
A number of MS patients in Ireland have been using it as part of a late stage clinical trial.
The drug works by helping damaged nerve fibres to conduct messages better by blocking tiny pores on the fibres.
The HSE said its manufacturer, Biogen Idec, does not currently have an arrangement in place for its funding under the community drugs schemes in accordance with the provision of the Health (Pricing and Supply of Medical Goods) Act 2013.
It also said Biogen Idec had failed to demonstrate or provide any formal justification of the prices proposed.
But the executive said it is open to Biogen submitting a new revised application, and would consider any such application in line with the processes formally agreed with the pharmaceutical industry.
HSE clinical lead for the Medicines Management Programme Professor Michael Barry said he will consider including Fampyra under the HSE community drug scheme if there is new evidence to suggest that the drug has a beneficial effect for patients or if Biogen lowers the price.
Speaking on RTÉ's Morning Ireland, Prof Barry said that when the decision was made not to include the MS drug under the scheme in 2012, there was not sufficient evidence to suggest it was successful.
However, he said new evidence may change this decision.
He also said that the drug would cost nearly €7,000 per patient per year which would potentially cost the state €20m over five years.
He suggested that this could take money from other healthcare, such as cancer therapy.
Biogen said it is committed to advancing and supporting MS care in Ireland and "strives to make our therapies available to all patients who need them"
It said it is "committed to working with authorities to ensure people living with MS who qualify for our treatments have access to them."
The company added that it remains committed to understanding the full benefit of Fampyra through continued investment in a clinical trial programme.