Around 8000 Scots with multiple sclerosis are being denied access to a drug that cuts the risk of disabling relapses by as much as 50%, it has been claimed.

The warning from campaigners came after the Scottish Medicines Consortium (SMC), which is responsible for approving newly-licensed drugs, rejected fingolimod for the treatment of NHS patients with relapsing-remitting MS – the most common form of the condition.

It said the daily pill, which replaces injections for sufferers, does not offer value for money for the health service.

Clinical trials have found it is twice as likely to prevent relapses compared to beta-interferon, the most commonly prescribed MS drug available on the NHS.

However, MS Society Scotland said the decision would "leave some people with no effective treatment option".

Director Patricia Gordon said: "Access to MS treatments in the UK is very poor and our hope is that the SMC and Novartis [the drug's manufacturer] can work together to make this treatment available to the people who need it. We will continue to campaign for improved access to treatments for all people with MS."

Neurologist Dr Belinda Weller, of the Western General in Edinburgh, the principal investigator for the Scottish branch of the trial, said: "I want to have the best options for my patients and there is a huge unmet need for an oral form of medication. Seven of the eight patients in the Edinburgh trial were very enthusiastic about its effects."

Fingolimod is widely available in Europe, the US and Canada, with the National Institute for Health and Clinical Excellence (Nice) due to issue its guidance on the drug to the NHS south of the Border this week.

Scotland has one of the highest rates of MS in the world, thought to be due to a combination of genetic factors and vitamin D deficiencies.

MS sufferer Claire MacRae, 35, has been taking fingolimod as part of the clinical trial since January 2011, after suffering a disabling relapse in October 2010 while on another drug. Ms MacRae, of Uphall, West Lothian, said she would consider moving to the US to get the treatment after her trial finishes.

"I've never relapsed since I've been on it, and it's been so much better taking a daily tablet instead of the horrible weekly injections with beta-interferon," said Ms MacRae. "It's stabilised everything. I still have the numbness in my legs, and vision problems in my left eye, but there's been no new damage. I'm scared I'll have to go back to using a less effective drug and then I'll suffer more relapses and be even more disabled."

Ms MacRae was a keen snowboarder when she was diagnosed in 2007 and now uses a walking stick. She quit her job 18 months ago.

Novartis is seeking clarification from the SMC about its ruling. A spokeswoman said it intended to submit further evidence about its effectiveness "as soon as possible".

The SMC said in addition to the value for money aspect of the drug, its trials did not compare it against natalizumab – another MS drug commonly used in Scotland.

A spokesman added: "We look forward to receiving new information when the manufacturer is able to provide it.

"In the meantime, all NHS boards in Scotland have systems in place to review individual requests for this medicine from any clinician who thinks that ... its use is appropriate for their patient."