Patients with heart conditions are being denied approved drugs which could reduce their risk of stroke and any future need for long-term institutional care, a cardiology expert has warned.
Doctors are "absolutely frustrated" at the "cumbersome" process required to get some treatments, Professor Keith Fox told MSPs.
Doctors can use an Individual Patient Treatment Request to prescribe drugs not approved for use on the NHS, but Prof Fox said there are also more common conditions for which a drug has been approved and licensed but is not available.
During an evidence session before Holyrood's Health Committee on access to new medicine, he described the difficulties facing consultants in getting new anti-coagulant drugs for patients with atrial fibrillation (irregular heartbeat).
"We have a really serious issue with a major under-recognition of the condition atrial fibrillation," said Prof Fox, who is Duke of Edinburgh professor of cardiology at Edinburgh University.
Around 125,000 people in Scotland have the condition, with about 15% of those aged over 80, he told the committee. "Why is it important? Because a quarter of those will have a stroke within five years," Prof Fox said.
Doctors are "absolutely frustrated" because they cannot use a treatment "systematically for a group of patients" even though it is approved for use on the NHS, he said.
Instead, doctors must go through the process on a patient-by-patient basis, which is "impossible" given the number of cases. "Getting through the process is so cumbersome that it is a barrier to those patients getting treatment that is proven in the evidence, accepted by the regulatory bodies, and accepted by the professionals," Prof Fox said.
"If you prevent stroke, you're preventing dementia and long-term institutional care among the elderly population.
"So what is our frustration is that here are treatments that can change that process, and change the proportion of individuals who will need long-term institutional care and they're not being implemented."