Renal Impairment Summary

Scope of this guidance

This guideline and associated dosage adjustment tables is intended for use in the management of community infections only.  The dosage tables contain simplified information for use of either eGFR or CrCl value. 

Clinical judgement should be used alongside any estimates derived from equations or suggested dose adjustments. This guideline does not apply to pregnant patients, critically ill patients where renal function is changing rapidly or those with acute kidney injury. Caution should be used when prescribing in dehydrated or oedematous patients. For further information on dosing in renal impairment, please consult the product SPC on www.hpra.ie.

Specialist advice should be sought to identify suitable alternative agents if the drug to be prescribed is cautioned or contraindicated in the renal prescribing tables.

Checking renal function is an important component of antimicrobial stewardship and safe prescribing

  • Several commonly prescribed antimicrobials do require dose adjustment in moderate to severe renal impairment.
  • Many antimicrobials do not need dose adjustment in mild renal impairment. It is important not to undertreat infections.
  • Checking renal function and adjusting antimicrobial dose or treatment regimen when appropriate:
    • optimises clinical outcome
    • prevents avoidable early discontinuation of antimicrobial therapy due to toxicity and adverse drug reactions
    • limits the selection of antimicrobial resistant strains.

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How to make dose adjustments in renal impairment

  • Prior to prescribing review recent estimates of renal function alongside the past pattern.
  • If renal impairment is considered likely on clinical grounds, renal function should be checked before prescribing any drug which requires dose modification.  Note that patients > 65 years of age are likely to have some degree of renal impairment.
  • Estimated glomerular filtration rate (eGFR) and creatinine clearance (CrCl) are two estimates of renal function available to prescribers.
  • eGFR (calculated by MDRD or CKD-EPI formula, units: ml/min/1.73m2):
    • usually calculated and reported by the laboratory when reporting renal function.
    • appropriate for most adult patients of average build and height and most drugs.
    • most likely to be inaccurate in people at extremes of body type (e.g. patients with limb amputations, severely malnourished and morbidly obese individuals).
  • CrCl (calculated by Cockcroft-Gault formula, units: ml/min):
    • For the antibiotics listed on this website, creatinine clearance (CrCl) calculated using the Cockcroft-Gault equation should be used to determine dosage adjustments, as opposed to eGFR, in the following clinical situations:

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  • CrCl can be calculated using applications such as MDCalc (https://www.mdcalc.com/creatinine-clearance-cockcroft-gault-equation)
    • If patient is overweight/obese, enter height to allow automatic calculation of adjusted body weight or ideal body weight as appropriate.
    • For further information on how to calculate CrCl using the MDCalc application, click on the thumbnail image below

MDCalc worked example (Click on the thumbnail image below for the full PDF)

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  • Use eGFR OR calculated CrCl figure to direct to relevant dosing column in tables below. 
Renal Impairment Prescribing Table – Antibacterials (Click on the thumbnail image below for the full PDF)

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Renal Impairment Prescribing Table – Antivirals (Click on the thumbnail image below for the full PDF)

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Renal Impairment Prescribing Table – Antifungal (Click on the thumbnail image below for the full PDF)

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Renal Impairment Prescribing Table - Anthelmintics (Click on the thumbnail image below for the full PDF)

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Reviewed September 2020