proposed amendment to the food and drug regulations project no. 1659 schedule f this notification announces the availability of a letter that provides an opportunity to comment on the proposed addition of six medicinal ingredients to part i of schedule f to the food and drug regulations. description of the medicinal ingredients 1. the current listing for amiodarone and its salts is revised to amiodarone its salts and derivatives. the revised listing is necessary to include the new medicinal ingredient dronedarone a derivative of amiodarone. amiodarone its salts and derivatives are used to treat irregular heartbeat. direct supervision by a practitioner with routine laboratory monitoring is required. there may be a narrow margin of safety between the therapeutic and toxic doses of amiodarone its salts and derivatives. 2. azacitidine its salts and derivatives are used to treat patients with blood diseases related to abnormal production of blood cells in the bone marrow but who are not eligible for stem cell transplantation. individualized instructions direct supervision by a practitioner and laboratory monitoring are required. there may be a narrow margin of safety between the therapeutic and toxic doses of azacitidine its salts and derivatives. 3. certolizumab pegol is a human monoclonal antibody used to treat active forms of rheumatoid arthritis an inflammatory disorder that affects tissues and organs. individualized instructions or direct supervision by a practitioner and routine laboratory monitoring are required. there may be a narrow margin of safety between the therapeutic and toxic doses of certolizumab pegol. 4. the current listing for cladribine and its salts is revised to cladribine its salts and derivatives. the revised listing is necessary to include the new medicinal ingredient clofarabine a derivative of cladribine. cladribine its salts and derivatives are used to treat leukemia. individualized instructions direct supervision by a practitioner and laboratory monitoring are required. there may be a narrow margin of safety between the therapeutic and toxic doses of cladribine its salts and derivatives. 5. degarelix its salts and derivatives are used to treat advanced prostate cancer by reducing levels of the hormone testosterone. individualized instructions or direct supervision by a practitioner is required. there are potential undesirable and severe side effects at normal therapeutic dosage levels of degarelix its salts and derivatives. 6. urokinase is an enzyme that is used to treat patients with severe blood clotting in the lungs pulmonary emboli or heart coronary artery thrombosis . individualized instructions or direct supervision by a practitioner is required along with monitoring against sudden and serious bleeding or infection. there are potential undesirable and severe side effects at normal therapeutic dosage levels of urokinase. 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.