proposed amendment to the food and drug regulations project no. 1591 schedule f the purpose of this letter is to provide an opportunity for comment on the proposed addition of eight medicinal ingredients to part i of schedule f to the food and drug regulations. description of the medicinal ingredients 1. ambrisentan is an endothelin receptor antagonist that is used to treat pulmonary arterial hypertension pah a condition characterized by high blood pressure in the pulmonary artery. 2. etravirine and its salts is an hiv non-nucleoside reverse transcriptase inhibitor nnrti . etravirine and its salts is used in the treatment of human immunodeficiency virus type 1 hiv-1 infection in patients for whom other hiv treatments are not effective. 3. methoxy polyethylene glycol-epoetin beta is a polymer-based erythropoietic compound that increases the number of red blood cells and hemoglobin level in the blood. methoxy polyethylene glycol-epoetin beta is used for the treatment of anemia in patients with chronic kidney disease. 4. the current listing for naltrexone and its salts is revised to naltrexone and its salts and derivatives. the revised listing is necessary to include the new medicinal ingredient methylnaltrexone bromide a derivative of naltrexone. naltrexone and its salts and derivatives are opioid receptor antagonists which block or lessen the action of opioid drugs such as morphine without causing a biological response of their own. methylnaltrexone bromide acts by reducing the effect of opioid drugs on the intestinal tract and is used to treat constipation in patients with advanced illness such as incurable cancer who are receiving opioid drugs on a continuous basis to alleviate pain. methylnaltrexone bromide is administered by injection under the skin. 5. nepafenac is a nonsteroidal anti-inflammatory drug nsaid that is used for management of eye pain and inflammation associated with cataract surgery. 6. panitumumab is a monoclonal antibody that acts on certain types of cancer cells and may prevent the cancer cells from growing or dividing. panitumumab is used to treat cancer of the colon or rectum that has spread to other parts of the body. 7. retapamulin is a topical antibiotic ointment that is used to treat bacterial skin infections such as impetigo and small infected cuts abrasions and sutured wounds. 8. sitagliptin and its salts is a member of a new class of medicines called dipeptidyl peptidase-4 dpp-iv inhibitors used to treat type ii diabetes. sitagliptin is used to improve blood sugar level in patients with type 2 diabetes mellitus in addition to diet and exercise. 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.