When enacted, the bill will allow for a system of generic substitution and reference pricing.
Campaigners against the legislation say that unlike most medications which are readily interchangeable, epilepsy medications are carefully concentrated for each individual to ensure good seizure control.
They warn that any variation in the manufacture and composition of a tablet or capsule introduces a factor that may disturb the balance. This may result in an otherwise avoidable or breakthrough seizure, even if the active ingredient is not changed.
A breakthrough seizure can have a significant negative effect for a person with epilepsy including for their employment status, ability to hold a driving license and social life.
A breakthrough seizure can also increase risk of physical injury and SUDEP (Sudden Unexpected Death in Epilepsy).
"Currently when a specific brand of medicine is prescribed for a person with epilepsy, a pharmacist can only supply that particular brand even when generic versions are available . . . This should remain the situation," says Professor Norman Delanty, Consultant Neurologist and Epileptologist and director of the Epilepsy Programme, Beaumont Hospital, and president of the Irish Epilepsy League.
"Anti- epileptic drugs should not be subject to generic substitution and should be permanently excluded from any legislation."
Countries that do not allow substitution of anti-epilepsy drugs for generics include the UK, Austria, Belgium, Czech Republic and Greece. In addition countries which have excluded many AEDs from substitution include Denmark, Finland, Germany, Portugal, Spain, Sweden and Switzerland.