| 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 |
[45] Amitriptyline, oral (migraine prophylaxis): National Department of Health: Affordable Medicines, EDP-Adult Hospital level. Medicine Review: Migraine prophylaxis, June 2018. http://www.health.gov.za/
Amitriptyline, oral (dose for migraine prophylaxis): Couch JR; Amitriptyline Versus Placebo Study Group. Amitriptyline in the prophylactic treatment of migraine and chronic daily headache. Headache. 2011 Jan;51(1):33-51. https://www.ncbi.nlm.nih.gov/pubmed/21070231
Amitriptyline, oral (dose for migraine prophylaxis): Loder E, Burch R, Rizzoli P. The 2012 AHS/AAN guidelines for prevention of episodic migraine: a summary and comparison with other recent clinical practice guidelines. Headache. 2012 Jun;52(6):930-45. https://www.ncbi.nlm.nih.gov/pubmed/22671714