title: Renal drug dosing recommendations: evaluation of product information for brands of the same drug.
abstract: OBJECTIVE
  To review the product information (PI) for various brands of the same generic drugs and investigate the extent to which information is currently available on dosing in renal impairment and the concordance between the dosing recommendations for the same generic drug.
  
  
  METHODS
  The Monthly Index of Medical Specialities (MIMS) was examined for 28 generic drugs recommended to be used with caution in renal impairment. For each generic drug all available brands listed as having solid oral dosage form were recorded. For each identified brand, the current PI was consulted and data referring to renal impairment was collated. The dissimilarity between these PI regarding the renal dosage recommendation was determined.
  
  
  RESULTS
  There was generally a lack of detailed information in the PI on the use of drugs in patients with renal impairment. The majority of PI documents (88 of 155 PI; 57%) provided quantitative dosage recommendations, but this was often not detailed enough to help users to make an informed decision. For 37 PI documents (24%), an altered dosage regimen was proposed without a quantifiable measure of renal function reported in the dose recommendation. The renal function severity category terms used and the associated quantitative values were also not consistent. It was observed that the recommendations varied among different brands of hydromorphone, morphine, oxycodone, tramadol, metformin and topiramate.
  
  
  CONCLUSIONS
  The reporting of renal function quantification methods, and associated dosage recommendations, in PI requires standardisation to ensure optimal drug dosing. Regularly updating of PI is also necessary.
authors.affiliation: Unit for Medication Outcomes Research and Education (UMORE), School of Pharmacy.
authors.forename: A
authors.initials: A
authors.lastname: Khanal
authors.forename: G M
authors.initials: GM
authors.lastname: Peterson
authors.forename: R L
authors.initials: RL
authors.lastname: Castelino
authors.forename: M D
authors.initials: MD
authors.lastname: Jose
mesh_terms: D000284:Administration, Oral; D019386:Alendronate / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000009:adverse effects; D002491:Central Nervous System Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D000075202:Contraindications; D004305:Dose-Response Relationship, Drug; D054796:Drug Dosage Calculations; D004348:Drug Labeling; D016568:Drugs, Generic / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D005919:Glomerular Filtration Rate; D006074:Gout Suppressants / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D007674:Kidney Diseases / Q000139:chemically induced* / Q000517:prevention & control; D007677:Kidney Function Tests; D009294:Narcotics / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D011619:Psychotropic Drugs / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D011899:Ranitidine / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D051436:Renal Insufficiency, Chronic / Q000378:metabolism
chemical_list: D002317:Cardiovascular Agents; D002491:Central Nervous System Agents; D016568:Drugs, Generic; D006074:Gout Suppressants; D007004:Hypoglycemic Agents; D009294:Narcotics; D004364:Pharmaceutical Preparations; D011619:Psychotropic Drugs; D011899:Ranitidine; D019386:Alendronate
keywords: GFR; drug dosing; glomerular filtration rate; kidney function; product information; renal impairment