| 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 |
[11] Metronidazole (as part of PPI triple therapy for H.pylori eradication): National Department of Health. Essential Drugs Programme. Medicine review: H.pylori eradication therapy for adults, 4 June 2020. http://health.gov.za/
Metronidazole (as part of PPI triple therapy for H.pylori eradication): Yuan Y, Ford AC, Khan KJ, et al. Optimum duration of regimens for Helicobacter pylori eradication. Cochrane Database Syst Rev. 2013;(12):CD008337. https://pubmed.ncbi.nlm.nih.gov/24338763/