| 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 |
[14] Carbamazepine, oral (trigeminal neuralgia): The National Institute for Health and Care Excellence. Neuropathic pain – pharmacological management, February 2017. NICE clinical guideline 173. http://guidance.nice.org.uk/CG173