dose adjustment in renal failure ...practical approach for clinical pharmacists
TRANSCRIPT
Dosing adjustment in
Renal Failure “Practical approach”
Kareem El-Fass PharmD,BpharmHead of Nephrology Clinical Pharmacy Department
Kidney and Urology Centre (KUC)
Estimation &/or Measurement of GFR
Exogenous Filtration Markers
Inulin, iothalamate, DTPA, iohexol
Endogenous Filtration Markers
Creatinine
Cystatin
How is Cr eliminated ?Glomerular Filtration
Tubular Secretion
10-20 % in
Normal
40-50 % in
diseased states
How is S.Cr performing for Kidney function assessment ??
Is a patient with s.cr =1.2 mg/dl is essentially free of
renal insult ???
How is Cr performing for Kidney function ??
1. Nephrotic syndrome
2. Sickle cell anemia Tubular secretion of
Cr
Decrease Cr secretion
Lupus Nephritis 3. Lupus Nephritis
How is Cr performing ??
How is Cr performing ??
How is Cr performing for Kidney function ??
Is a patient with s.cr =1.2 mg/dl is essentially free of
renal insult ??? S.Cr =1.1 mg/dl
GFR =120 ml/min
S.Cr = 1.2 mg/dl
GFR =60 ml/min
How is Cr performing for Kidney function ??
How is Cr measured ?
1. Jaffe Method (Alkaline Picrate)
2. Isotope Dilution Mass Spectroscopy
(IDMS) (SCr [IDMS] = 0.95 x SCr [Jaffe]).
Crcl Vs GFR e
e-GFR for CKD Classification
eGFR GFR estimated by equations incorporating tubular
secretion such as 1.MDRD
eGFR GFR estimated by equations incorporating tubular
secretion such as 2. CKD-EPI KDIG
O 2012
eGFR1. When measured GFRs >60 where they
underestimate
2. When measured GFR <60 as they overestimate.
Now ……what equation shall we use for dosing ???
Cockcroft-Gault
ml/min
Actual BW Jaffe
only
FDA
Stable only
NKF Recommendations
1. Use of either CG or MDRD for dose
adjustments yields little difference .
2. When MDRD is used it should be normalized
ASHP 2010 Recommendations
1. Calculate CrCl using Cockcroft-Gault
equation
2. Identify suggested dosage adjustment
3. Determine if the dosage adjustment is
logical and appropriate for your patient
What to do for ??
1.Unstable creatinine (AKI)
What to do for ??
2. Different weightsPharmacotherapy 2012
What to do for ??
2. Different weights Weight category Equation to use
Underweight BMI of 18.5 kg/m2
Actual Body weight
Normal weight BMI of 18.5–24.9 kg/m2
IBW
Obese and Overweight BMI of 25 -40 kg/m2
Adjusted Body weight 0.4
Morbidly obese MBI 40 kg/m2 or higher
Lean body weight
What to do for ??
2. Different weights
What to do for ??
2. Different weights
http://www.pharmacologyweekly.com/app/medical-calculators/body-mass-index-bmi-weight-bsa-calculator
Where to go for CrCl and e-GFR Calculation ?
• http://www.globalrph.com/multiple_crcl_2012.cgi
How to get recommendations for dosing
• Check Many references Allopurinol
How to get recommendations for dosing
• Check Many references Allopurinol
How to get recommendations for dosing
• Check Many references Allopurinol
Take-Home Messages
1. Keep Cr limitations in your sight
2. Take care of equation you use and its limitation
3. Use appropriate body weight and s.cr
4. Check different resources
5. Clinical consequences follow-up