| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[12] Morphine, long-acting: National Department of Health, Essential Drugs Programme: Adult Hospital level STG, 2015. http://www.health.gov.za/
Morphine, long-acting, oral: South African Medicines Formulary. 12th Edition. Division of Clinical Pharmacology. University of Cape Town, 2016.
Morphine, long-acting, oral: National Department of Health: Affordable Medicines, EDP-PHC. Medicine Review. Oxycodone for chronic cancer pain in adults, June 2018. http://www.health.gov.za/
Morphine, long-acting, oral: Schmidt-Hansen M, Bennett MI, Arnold S, Bromham N, Hilgart JS. Oxycodone for cancer-related pain. Cochrane Database Syst Rev. 2017 Aug 22;8:CD003870. https://www.ncbi.nlm.nih.gov/pubmed/28829910