proposed amendment to the food and drug regulations project no. 1597 schedule f 5 pages available in english and french this notification announces the availability of a letter that provides an opportunity to comment on the proposed addition of three medicinal ingredients to part i of schedule f to the food and drug regulations. description of the medicinal ingredients 1. idebenone is a benzoquinone derivative that is used to manage symptoms of freidreichs ataxia. freidreichs ataxia is an inherited disease that causes progressive damage to the nervous system resulting in symptoms ranging from difficulty walking to speech problems and also frequently leads to heart disease. idebenone should only be prescribed by or following consultation with practitioners who are experienced in the diagnosis and management of freidreichs ataxia. direct supervision by a practitioner is required during treatment. 2. idursulfase is an enzyme that is manufactured using recombinant deoxyribonucleic acid dna technology. idursulfase is used to treat deficiency ofthe enzyme iduronate-2-sulfatase in patients with hunter syndrome a seriousprogressive genetic disorder that can result in permanent damage such as visionand hearing loss heart disease breathing difficulties and joint stiffness. direct supervision by a practitioner and routine laboratory monitoring are required. 3. nesiritide belongs to a new drug class that is manufactured using recombinant deoxyribonucleic acid dna technology. nesiritide is used to treat patients in hospital who have symptoms of heart failure and have not responded to treatment with other drugs. direct supervision by a practitioner is required. nesiritide may cause undesirable or severe side effects at normal therapeutic dosage levels. the degree of regulatory control afforded by schedule f prescription drug status coincides with the risk factors associated with each medicinal ingredient. oversight by a practitioner is necessary to ensure that appropriate risk benefit information is considered before the drug containing the medicinal ingredient is administered and that the drug therapy is properly monitored. schedule f is a list of medicinal ingredients the sale of which is controlled under sections c.01.041 to c.01.049 of the food and drug regulations. part i of schedule f lists ingredients that require a prescription for human use and for veterinary use. part ii of schedule f lists ingredients that require a prescription for human use but do not require a prescription for veterinary use if so labelled or if in a form unsuitable for human use.