| 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 |
[20] Allopurinol, oral – renal adjusted dosing: Siu YP, Leung KT, Tong MK, Kwan TH. Use of allopurinol in slowing the progression of renal disease through its ability to lower serum uric acid level. Am J Kidney Dis. 2006;47(1):51–59. https://www.ncbi.nlm.nih.gov/pubmed/16377385
Allopurinol, oral – renal adjusted dosing: Goicoechea M, de Vinuesa SG, Verdalles U, Ruiz-Caro C, Ampuero J, Rincón A, Arroyo D, Luño J. Effect of allopurinol in chronic kidney disease progression and cardiovascular risk. Clin J Am Soc Nephrol. 2010 Aug;5(8):1388-93. https://www.ncbi.nlm.nih.gov/pubmed/20538833
Allopurinol, oral – renal adjusted dosing: South African Medicines Formulary. 12th Edition. Division of Clinical Pharmacology. University of Cape Town, 2016.
Allopurinol, oral – renal adjusted dosing: Bennet et al. Drug Prescribing in Renal Failure. 5th Edition. Philadelphia: American College of Physicians. 2007;104.