| 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 |
[31] Salbutamol, IV: Neilson JP, West HM, Dowswell T. Betamimetics for inhibiting preterm labour. Cochrane Database Syst Rev. 2014 Feb 5;2:CD004352. http://www.ncbi.nlm.nih.gov/pubmed/24500892
Salbutamol, IV: South African Medicines Formulary. 12th Edition. Division of Clinical Pharmacology. University of Cape Town. 2016.