Renal Dosing


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General Principles

General Principles

  1. Many medicines are excreted by the kidneys and require dose adjustment in renal impairment to avoid toxicity.
  2. Antimicrobial dosage depends on the type and severity of the infection, sensitivity of the causative organism and the general condition of the patient. For severe infections the higher end of the dose range should be used.
  3. For some drugs, although the size of the maintenance dose is reduced, it is important to still give a loading dose when recommended.
  4. Caution if concomitant hepatic and renal impairment – a further reduction in dosing may be indicated.
  5. There is inconsistency among published sources of information on drug dosing in renal impairment. Recommendations in these guidelines are largely derived from The Renal Drug Database (RDD), which in some cases may be higher than the manufacturer’s recommendations in the Summary of Product Characteristics (SPC) and the BNF.
  6. Doses of Antimicrobials in Renal impairment are outlined in Table . Antimicrobials marked with an asterix have significant differences in dosing between reference sources. In some cases a dose range is given – the higher end of the range should be used for severe infections. See HPRA.ie for licensed dose recommendations.
  7. “Usual” dose refers to the dose and interval recommended for adults with normal renal and hepatic function in GUH Antimicrobial Guidelines.


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Assessing Renal Function

Assessing Renal Function

1. Published information on the effects of renal impairment on drug elimination is usually stated in terms of creatinine clearance, calculated using Cockcroft & Gault equation, as a surrogate for GFR.

2. The Evolve system reports renal function as eGFR (estimated glomerular filtration rate) normalised to a body surface area of 1.73m 2 , calculated using the CKD-EPI equation.

3. Although the two measures of renal function are NOT interchangeable, for most drugs and for most adult patients of average build and height, eGFR (rather than CrCl) can be used to determine dosage adjustments.

4. The BNF now uses eGFR for dose reduction for most (but not all) drugs, as does the Dosing Table for Antimicrobials in Renal impairment . Exceptions to the use of eGFR, where calculation of creatinine clearance (Cockcroft & Gault equation) is recommended, include:

  • Elderly patients aged 75 years and over
  • Patients at extremes of muscle mass (BMI less than 18 kg/m 2 or greater than 40 kg/m 2 )
  • Nephrotoxic drugs and drugs with a narrow therapeutic index that are mainly renally excreted. The BNF doesn’t specify which drugs but examples specified in the Dosing Table include:
    • Aminoglycosides (e.g. Amikacin, Gentamicin, Tobramycin)
    • Vancomycin
    • Foscarnet
    • Ganciclovir
    • Valganciclovir

5. Using serum creatinine to derive eGFR has a number of limitations; serum creatinine levels are dependent on muscle mass and diet, therefore estimates should be interpreted with caution in certain individuals (such as the elderly, body builders, amputees, in muscle-wasting disorders and vegans)—estimates will be higher or lower than the true value.

6. Creatinine-derived measurements are also not useful in periods of rapidly changing renal function (e.g. critical care) or in patients with Acute Kidney Injury (AKI).

7. In principle, in the acutely critically ill patient with AKI, antimicrobials with wide therapeutic indices and minimal safety concerns e.g. beta lactams should/may be given at full dose for the first 24-48h. Regular monitoring of renal function is advised in acutely ill patients to ensure drug use and dosing is appropriate.

8. Dosing should be assessed on an individual patient basis, balancing risk versus benefit, and taking urine output and clinical picture into account.

9. The gentamicin calculator incorporates a creatinine clearance (CrCL) calculator, which calculates CrCl (ml/min) using Cockcroft and Gault . This may be used for dose adjustment for other antimicrobials.


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Cockcroft and Gault Equation

Cockcroft and Gault Equation

Creatinine Clearance (CrCl) (ml/min)

1.Calculate Ideal Body Weight (IBW) in kg (see below)

2. If actual body weight < IBW,  use actual body weight in this equation

N = 1.23 males & 1.04 females

Ideal Body Weight (IBW) (kg) =

Male:

50kg + (2.3kg x inches over 5 feet) OR 50kg + (0.9kg x cm over 152cm)

Female:

45.5kg + (2.3kg x inches over 5 feet) OR 45.5kg + (0.9kg x cm over 152cm)


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Renal Replacement Therapy

Renal Replacement Therapy

  • Intermittent Haemodialysis (IHD) : Assume GFR <10ml/min . Many drugs are removed by haemodialysis. If dialysed, it is recommended to time administration to take place post dialysis and at the same time every day including dialysis days (to avoid the need to give a supplemental dose post dialysis). In GUH medium flux filters are most commonly used for intermittent haemodialysis, although high flux filters may be used for some patients.
  • A haemodialysis unit guideline summarises dosing of Vancomycin, CefAZOLin, Daptomycin & Gentamicin for patients with chronic renal impairment on IHD.
  • Continuous renal replacement therapy (CRRT): Recommendations for dosing of antimicrobials for patients on CRRT in critical care are not covered in these guidelines. In GUH, continuous venovenous haemodiafiltration (CVVHDF) is the type of continuous renal replacement used. ICU pharmacist is available for advice during working hours.


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Dosing Table for Antimicrobials in Renal Impairment

Dosing Table for Antimicrobials in Renal Impairment

  1. This dosage adjustment table is intended for use in the treatment of infection of hospitalised patients only.
  2. It recommends dose adjustment using the patient’s eGFR value (or Creatinine Clearance using Cockcroft and Gault (CrCL) if specified).
  3. Please refer to General principles and Assessing Renal function . Clinical judgement should be used alongside any estimates derived from equations or suggested dose adjustments.
  4. For some medicines, the renal dose information is presented as a dose range –use the higher end of the dose range for severe infections. Antimicrobials marked with an *asterix have significant differences in dosing between reference sources.
  5. In situations where a range of dosing is recommended, patient, indication and severity of infection need to be considered. Specific factors include age, immune function, degree of renal impairment, risk of adverse effects etc.
  6. More detailed information on some antimicrobials is available in GUH IV guides . See links in individual monographs.
  7. “Usual” dose refers to the dose and interval recommended for adults with normal renal and hepatic function in GUH Antimicrobial Guidelines.

Doses of Antimicrobials in Renal Impairment (Adults)

Antimicrobial

eGFR (ml/min/1.73m 2 )

Comment

20 to 50

10 to 20

<10

Aciclovir IV

If obese, use ideal or adjusted body weight to calculate dose - See IV guideline for details.

eGFR 25 to 50

Usual dose

every 12h

eGFR 10 to 25

Usual dose

every 24h

eGFR <10

50% of usual dose every 24h

Maintain adequate hydration. Risk of crystalluria / neurological reactions increased.

Amikacin

CrCl < 80 : Reduce dose. See Amikacin Dosing Table

Monitor levels.

Must use CrCl (not eGFR).

*Amoxicillin IV/PO

eGFR 10 to 50

Usual

eGFR <10

250mg to 1g q8h

High dose regimens e.g. endocarditis & listeria meningitis: max 2g q8h

Amphotericin Liposomal

AmBisome ®

Usual

Highly nephrotoxic – monitor renal function, potassium  and magnesium

Anidulafungin

Usual

Artesunate

Usual

Ref: SPC

Atovaquone

eGFR 10 to 50

Usual dose

eGFR <10

Usual dose with caution

Monitor more closely in renal impairment.

Azithromycin

Usual but use with caution if eGFR <10

33% increase in systemic exposure to azithromycin in patients when GFR<10

Aztreonam

eGFR 30 to 50

Usual

eGFR 10 to 30

Usual first dose, then 50% of usual dose

eGFR <10

Usual first dose, then 25% of usual dose

Nebulised: Dose as in normal renal function

Benzylpenicillin

eGFR 20 to 50

Usual

eGFR 10 to 20

600mg to 2.4g q6h

eGFR <10

600mg to 1.2g q6h

Increased risk of neurotoxicity (seizures) in renal impairment

Use higher doses for severe infection only e.g. endocarditis

Caspofungin

Usual

*CefALEXin

eGFR 40 to 50

Usual

eGFR 10 to 40

500mg q8h

eGFR <10

500mg q12-24h

*CefAZOLin

eGFR 35-54

Usual dose q8h

eGFR 11-34

1-2g q12h

eGFR <10

1-2g q24h

Haemodialysis

See Haemodialysis Dosing Guidelines

Ref: Sanford, Stanford.

High doses in severe infection as per ID/Micro only.

Caution - Increased risk of convulsions in renal impairment

CefoTAXime

eGFR 5 to 50

Usual

eGFR <5

Reduce dose by 50% and keep frequency the same.

For severe/life-threatening infection contact Micro/ID

Reduce dose further if concurrent hepatic and renal failure.

CefTAROLine

Standard dose: 600mg q12h

eGFR 31 to 50

400mg q12h

eGFR 15 to 30

300mg q12h

eGFR <15

200mg q12h

High dose: 600mg q8h 400mg q8h 300mg q8h 200mg q8h

CefTAZidime

eGFR 31 to 50

1g to 2g q12h

eGFR 16 to 30

1g to 2g q24h

eGFR 6 to 15

500mg to 1g q24h

eGFR <5

500mg to 1g q48h

CefTAZidime/

Avibactam (Zavicefta)

On Micro or ID approval only

eGFR 31 to 50

1.25g q8h

eGFR 16 to 30

0.94g q12h

eGFR 6 to 15

0.94g q24h

eGFR <6

0.94g q48h

Ref: SPC

Ceftolozane/

Tazobactam (Zerbaxa)

On Micro or ID approval only

eGFR <50

Reduce dose. Renal dose depends on indication. See IV Guide.

CefTRIAXone

eGFR 10 to 50

Usual

eGFR <10

Usual to max 2g q24h

Meningitis only: 2g BD (see comment)

High dose (Ref Sanford) in meningitis in eGFR <10 to be discussed with Micro/ID .

Max 2g q24h if severe renal impairment in combination with hepatic impairment

CefUROXime IV

eGFR 20 to 50

Usual

eGFR 10 to 20

750mg to 1.5g

q12h

eGFR <10

750mg to 1.5g

q24h

*CefUROXime PO

Usual

Chloramphenicol

eGFR 10 to 50

Usual

eGFR <10

Usual - but use only if no alternative (BNF)

Monitor levels in renal impairment (but not routinely available). See IV guide for additional information

*Ciprofloxacin IV/PO

eGFR 30 to 50

Usual

eGFR 10 to 30

50 to 100% of usual dose

eGFR <10

50% of usual dose but if severe infection discuss with Micro or ID (may consider higher dose for short period)

Higher end of dose range for severe infection should be discussed with Micro/ID .

Caution-Higher risk of tendon injury in renal impairment - see Quinolone warning

*Clarithromycin IV/PO

eGFR 30 to 50

Usual

eGFR<30

250 to 500mg q12h. Use higher end of dose range for severe infection.

Avoid if severe hepatic failure also present. May cause vomiting if eGFR <10

Clindamycin IV/PO

Usual dose but see comment if eGFR <10

Dosage reduction or monitoring may be necessary in severe renal impairment (SPC, RDD)

Co-amoxiclav IV

eGFR 30 to 50

Usual

eGFR<30

1.2g q12h

*Co-amoxiclav PO

Moderate – Severe infection

Usual Dose

For mild infection, see SPC for alternative licensed dosing recommendations

Colistin IV

Conventional dosing (CF)        (1-2MU q8h)

CrCl <20

Reduce dose. Renal dose depends on indication. See IV Guide.

Must use CrCl (not eGFR).

Colistin IV

High dose regimen (non-CF) (9MU, then 4.5MU q12h)

On Micro or ID approval only

CrCl <50

Reduce dose. Renal dose depends on indication. See IV Guide .

Must use CrCl (not eGFR).

*Co-trimoxazole IV/PO

Treatment doses only

eGFR 30 to 50

Usual

eGFR 15 to 30

PJP : Usual dose for 3 days, then 30mg/kg q12h

Other indications: 50% of dose

eGFR <15 (Use only if haemodialysis facilities available)

PJP : 30mg/kg q12h

Other indications: Avoid if possible if levels cannot be monitored (or use 50% of dose if ID/Micro approved)

Monitor levels in renal impairment (but not routinely available)

Dapsone

eGFR 20 to 50

Usual dose

eGFR 10-20

Usual dose

Use with caution

eGFR <10

50-100mg daily. Use with caution. No dose reduction is required for malaria prophylaxis.

Regular blood counts in renal impairment

Daptomycin

On Micro or ID approval only

eGFR 30 to 50

Usual

eGFR <30

Usual dose q48h

Caution in renal impairment- monitor renal function & CPK closely if eGFR <80

Doxycycline

Usual

Erythromycin IV/PO

Usual

Increased risk of ototoxicity in renal impairment especially at high doses. Max 1.5g daily in severe renal impairment

Ethambutol

eGFR >30

Usual

eGFR <30

15 - 25mg/kg (Max 2.5g)

3 times/week

Preferably avoid in renal impairment. Monitor levels if eGFR <30 (but not routinely available)

Fidaxomicin

On Micro or ID approval only

Usual

Use with caution in severe impairment

Flucloxacillin IV/PO

eGFR 10 to 50

Usual

eGFR <10

Usually max 1g IV q6h but may require 2g IV q6h if recommended by Micro or ID e.g. for endocarditis

Use with caution if concomitant liver impairment/ consider lower doses.

Accumulation of electrolytes can occur

Fluconazole IV/PO

eGFR 10 to 50

Usual initial dose then 50-100% dose

eGFR <10

Give usual initial dose as a loading dose, then 50% of dose

Flucytosine IV

eGFR 20 to 40

50mg/kg q12h

eGFR 10 to 20

50mg/kg q24h

eGFR <10

50mg/kg stat, then dose according to levels. Dose of 0.5 to 1g daily is usually adequate.

Must use CrCl (not eGFR). Monitor levels (but not routinely available)

Foscarnet

Reduce dose. See IV Guide .

Must use CrCl (not eGFR).

Maintain adequate hydration.

Fosfomycin PO

On Micro or ID approval only

eGFR 10 to 50

Uncomplicated UTI: 3g as a single dose

eGFR <10

Avoid

Fosfomycin IV

On Micro or ID approval only

eGFR<40

Reduce dose according to indication. See IV Guide .

SPC advises use with caution in renal impairment

Fusidic Acid

Usual

Ganciclovir

CrCl <70

Reduce dose. See IV Guide .

Must use CrCl (not eGFR).

Maintain adequate hydration.

Gentamicin

CrCl <80 : Reduce dose. See Gentamicin Dosing Table

CrCl <10 on haemodialysis : See Haemodialysis Dosing Guidelines

Monitor levels. Must use CrCl (not eGFR).

Isavuconazole

On Micro or ID approval only
Usual

Isoniazid

eGFR 10 to 50

Usual

eGFR <10

200 to 300mg q24h

Itraconazole PO

Usual

Itraconazole IV

eGFR 30 to 80

Use with caution

eGFR<30

Avoid

IV vehicle may accumulate in renal impairment

Levofloxacin IV/PO

On Micro or ID approval only

eGFR 20 to 50

500mg stat, then 250mg q12h

eGFR 10 to 20

500mg stat, then 125mg q12h

eGFR <10

500mg stat, then 125mg q24h

Based on usual dose of 500mg q12h

Caution-Higher risk of tendon injury in renal impairment - see Quinolone warning

Linezolid IV/PO

On Micro or ID approval only

Usual

Monitor FBC closely if eGFR <10

Caution in CrCl <30. Monitor platelets and for serotonin syndrome in renal impairment

Meropenem

On Micro or ID approval only

eGFR 26 to 50

500mg to 2g q12h

eGFR 10 to 25

500mg to 1g q12h

eGFR <10

500mg to 1g q24h

Higher end of dose range for CNS / MDRO infection should be discussed with Micro/ ID.

Metronidazole IV/PO

Usual

Moxifloxacin IV/PO

On Micro or ID approval only

Usual

Caution-Higher risk of tendon injury in renal impairment - see Quinolone warning

Nitrofurantoin

eGFR <45

Contraindicated.

However, a short 3 to 7 day course may be used with caution in certain patients with an eGFR of 30 to 44 - to treat lower UTI with suspected/proven multidrug resistant pathogens when the benefits of nitrofurantoin are considered to outweigh the risks of side effects.

May be ineffective in eGFR <60ml/min (RDD) due to inadequate urinary concentration; risk of peripheral neuropathy. Monitor for pulmonary adverse events

*Ofloxacin

eGFR 10 to 50

200 to 400mg q24h

eGFR <10

100 to 200mg q24h

Caution-Higher risk of tendon injury in renal impairment - see Quinolone warning

Oseltamivir

Treatment dose

CrCl 31 to 60

30mg q12h

CrCl 11 to 30

30mg q24h

CrCl ≤10

30mg one dose

Ref HPSC (Dose in CrCl <10 based on expert opinion as per HPSC, PHE)

Use CrCl if available; otherwise use eGFR

Oseltamivir

Prophylaxis dose

CrCl 31 to 60

30mg q24h

CrCl 11 to 30

30mg q48h

CrCl ≤10

30mg one dose, repeat after 7 days

Ref: HPSC

(Dose in CrCl <10 based on expert opinion as per HPSC, PHE)

Use CrCl if available; otherwise use eGFR

Oxytetracycline

e GFR 10 to 50

Usual (but see comment)

eGFR <10

250mg q6h

Avoid if possible in renal impairment (RDD). May exacerbate renal failure. Use only if essential (SPC)

Pentamidine

eGFR 10 to 50

Usual

eGFR <10

PJP Severe infection : 4mg/kg once daily IV for 7-10 days, then 4mg/kg on alternate days to complete the course of at least 14 doses

PJP Non-severe infection :

4mg/kg IV on alternate days to complete the course of at least 14 doses

Phenoxymethyl-penicillin

Usual

Piperacillin/

tazobactam

eGFR 20 to 40

4.5g q8h

eGFR <20

4.5g q12h

Posaconazole IV/PO

Oral: Usual

IV: eGFR<50: Avoid IV if possible (use oral), unless benefit of IV outweighs risk.

IV vehicle may accumulate in renal impairment

Pyrazinamide

eGFR 30 to 50

Usual

eGFR <30

25-30mg/kg 3 times/week

Ref: BNF & WHO

Quinine IV

Oral: Usual

IV for treatment of malaria: see IV guide

Ref: BNF & WHO

Rifampicin

eGFR 10 to 50

Usual

eGFR <10

50 to 100% of usual dose

TB : Give usual dose

Use with caution  in renal impairment if dose above 600mg daily, elderly or co-existing liver impairment

Teicoplanin

eGFR 30 to 80

Give usual dose on days 1 to 4, then give usual dose q48h

eGFR <30

Give usual dose on days 1 to 4, then give usual dose q72h

Levels are not routinely available

Tigecycline

Usual

Tobramycin

Monitor levels.

Must use CrCl (not eGFR).

*Trimethoprim

eGFR 15-30

Use normal dose for treatment – See Comment.

eGFR <15

50-100% of normal dose (RDD)

May cause temporary rise in creatinine due to competition for renal secretion rather than a fall in CrCl, therefore avoid in those where acute rises in creatinine would complicate the clinical picture.

Can cause hyperkalaemia, do not use in patients with CrCl<30ml/min where hyperkalaemia is a problem or if they are on other medications which can cause hyperkalaemia (e.g. ACE inhibitor, spironolactone)

ValACIclovir

Reduce dose according to indication and renal function

HSV: eGFR <30: Reduce dose

Herpes zoster: eGFR <50: Reduce dose

CMV prophylaxis: eGFR <75: Reduce dose

See Renal Drug Database www.renaldrugdatabase.com

Maintain adequate hydration

ValGANCIclovir

CrCl <60

Reduce dose. See Renal Drug Database www.renaldrugdatabase.com and/or specialist centre advice.

Must use CrCl (not eGFR).

Maintain adequate hydration

Vancomycin IV

CrCl <50 : Reduce dose. See Vancomycin Dosing Table

CrCl <10 on haemodialysis : See Haemodialysis Dosing Guidelines

Monitor levels. Must use CrCl (not eGFR)

Voriconazole IV/PO

Oral: Usual

IV: eGFR<50: Avoid IV if possible (use oral), unless benefit of IV outweighs risk.

IV vehicle may accumulate in renal impairment

*Antimicrobials marked with an *asterix have significant differences in dosing between reference sources


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Vancomycin, CefAZOLin, Daptomycin & Gentamicin Dosing in Haemodialysis

Vancomycin, CefAZOLin, Daptomycin & Gentamicin Dosing Guidelines for Patients on Intermittent Haemodialysis

Loading dose

Maintenance dose

Administration

For inpatients, administer in haemodialysis unit and record on inpatient drug chart

Monitoring

Not usually necessary to hold the dose pending levels unless previous level high or toxicity suspected

Vancomycin

  • A loading dose is essential to ensure adequate plasma levels
  • Give 20mg/kg loading dose rounded to nearest 250mg

Weight

Dose

750mg with each dialysis

During latter part of dialysis, by infusion

  • Pre-dialysis trough level
  • Check first trough level before the second dose, then once weekly
  • Target trough 15 to 20mg/l
  • The goal is to ensure effective plasma levels

<50kg

750mg

500mg in 100ml NaCl 0.9%

or glucose 5% over 60 mins

50-69kg

1g

750mg to 1g in 250ml NaCl 0.9% or glucose 5% over 100 minutes

70-100kg

1.5g

1.5g in 250ml NaCl 0.9% or glucose 5% over 150 minutes

>100kg

2g

2g in 500ml NaCl 0.9% or glucose 5% over 200 minutes

CefAZOLin

No loading dose required

Give 2g/2g/3g three times weekly with each dialysis: 2g when next dialysis 2 days later, and 3g when next dialysis 3 days later

Post dialysis, by IV infusion in 50ml NaCl 0.9% or glucose 5% over 15 minutes

Reconstitute each 1g vial with 2.5ml Water for Injection

None required

Daptomycin

No loading dose required

Give 6/6/9 mg/kg three times weekly with each dialysis: 6mg/kg when next dialysis 2 days later, and 9mg/kg when next dialysis 3 days later

Post dialysis, by slow IV injection over 2 minutes

None required

Gentamicin

2mg/kg

to max 160mg

Use ABW, unless ABW >30% above IBW,

then use dosing wt =

IBW + 0.4 (ABW-IBW)*

1mg/kg with each dialysis (max 80mg)

Use ABW unless ABW

>30% above IBW,

then use dosing wt =

IBW + 0.4 (ABW-IBW)*

Post dialysis, by slow IV push over 2 minutes in wash back

  • Trough level at end of dialysis but immediately prior to dose
  • Target trough less than 2mg/l
  • The goal is to minimise toxicity and to ensure effective plasma levels

*IBW – ideal body weight; ABW – actual body weight.    IBW (kg) = 50 (45.5 for women) + (2.3 x inches over 5 feet)

Further Information: Vancomycin: 80-90% excreted unchanged by the kidneys. Not significantly removed by conventional HD, removal increased by high flux HD. Gentamicin: 100% excreted unchanged by the kidneys. 30% removed during 4 hour HD

Developed by GUH Pharmacy & Nephrology Depts

Ref: IDSA Guidelines for the diagnosis and management of intravascular catheter-related infection. Clin Infect Dis 2009;49:1-45


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References

References

  1. The Renal Drug Database www.renaldrugdatabase.com Accessed Feb 2021
  2. BNF accessed online via Medicines Complete Feb 2021
  3. Health Products Regulatory Authority. Summary of Product Characteristics (SPC): www.HPRA.ie
  4. The Sanford Guide to Antimicrobial Therapy Digital Update Accessed Feb 2021
  5. Johns Hopkins POC-IT ABX Guide. The Johns Hopkins University Accessed Feb 2021
  6. GUH IV Administration Guide
  7. Renal dosing of antibiotics: Are we jumping the gun? Clinical Infectious Diseases, 68 (9). 1596-1602 May 2019
  8. Nottingham University Hospital Antimicrobial Doses for Adults in Renal Impairment September 2019 https://www.nuh.nhs.uk/download.cfm?doc=docm93jijm4n629.pdf&ver=19071

Acknowledgements

Written by Marie Tierney & Dr. Úna NíRiain May 2012, Updated March 2021.

Reviewed by pharmacists and nephrologists in GUH, PUH. Approved by Antimicrobial Stewardship Team.