Carboplatin AUC Calculator
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Age:
Scr:
Sex:
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Height:
Weight:
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Target AUC:
(mg/ml/min) |
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Is this a previously treated patient? :
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Is the serum creatinine (Scr) currently stable:
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Background
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CALVERT FORMULA FOR CARBOPLATIN DOSING:
Total Dose (mg) = (target AUC) x (GFR + 25)
Calvert AH, Newell DR, Gumbrell LA, et al. Carboplatin dosage: prospective
evaluation of a simple formula based on renal function. J Clin Oncol.
1989;7:1748-1756.
AUC = target area under the concentration versus time curve
in mg/mL•min.
GFR was measured by 51Cr-EDTA clearance. Estimations of GFR
are frequently used in clinical practice, however, several important points
should be reviewed (see below).
Relevant package insert data:
Previously treated patients: a target AUC of 4-6 mg/mL•min using single
agent Carboplatin Inj appears to provide the most appropriate dose range.
For patients who previously DID NOT receive chemotherapy (untreated), a
target AUC of 7 (range: 6-8) mg/mL per minute has been recommended when
carboplatin is used alone.
Dose Adjustment Recommendations: Pretreatment platelet count and performance
status are important prognostic factors for severity of myelosuppression in
previously treated patients. The suggested dose adjustments for single agent
or combination therapy shown in the table below are modified from controlled
trials in previously treated and untreated patients with ovarian carcinoma.
Blood counts were done weekly, and the recommendations are based on the
lowest post-treatment platelet or neutrophil value.
Platelets
Neutrophils
Adjusted Dose* (From Prior Course)
>100,000
>2000
125%
50-100,000 500-2000
No Adjustment
<50,000
<500
75%
Important points
1) The use of the Calvert formula in patients with a GFR or CRCL less than
15 to 20 ml/min is not recommended based on insufficent accuracy.
Package insert: The data available for patients with severely impaired
kidney function (creatinine clearance below 15 mL/min) are too limited to
permit a recommendation for treatment.
2) Flucuating serum creatinine values DO NOT provide an accurate CrCl
estimate.
3) GFR estimation: Definitive guidelines or method of determination has not
been firmly established. Unreliable results may be obtained in patients who
are outside the normal weight range (e.g. obese or cachectic patients).
4) The package insert does not provide a specific formula for GFR
estimation.
5) AUC-based carboplatin dosing is more accurate than dosing according to
BSA.
6) Several factors must be considered in addition to the GFR to determine
the precise dosage. Additional factors that should be assessed include:
previous exposure to chemotherapy or radiotherapy, and overall health
status. |
References
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Carboplatin dosage
Calvert AH, Newell DR, Gumbrell LA, et al. Carboplatin dosage: prospective
evaluation of a simple formula based on renal function. J Clin Oncol.
1989;7:1748-1756.
Estimated Clearance Equations
Cockcroft and Gault equation:
Male: CrCl (ml/min) = (140 - age) x wt (kg) / (serum creatinine x 72)
Female: Multiply above result by 0.85
Reference:
Cockcroft DW, Gault MH. Prediction of creatinine clearance from
serum creatinine. Nephron 1976;16(1):31-41.
The original Cockcroft and Gault equation utilized total body weight,
however, the most commonly used version of this equation incorporates the
Ideal body weight (IBW) or an adjusted body weight (ABW) in obese patients
whose actual weight is significantly greater than their IBW.
Ideal body weight (IBW):
IBW (males) = 50 kg + 2.3 x (height [inches] − 60)
IBW (females) = 45.5 kg + 2.3 x (height [inches] − 60)
Reference:
Devine BJ. Gentamicin therapy. DICP. 1974; 8:650–5.
Adjusted body weight (ABW):
ABW (kg) = ideal body weight + [0.4 * (actual
body weight - ideal body weight)]
Reference:
1) Bauer LA. Applied clinical pharmacokinetics. New York: McGraw Hill,
Medical Publishing Division; 2001:93-179.
2) Winter, M.E., 2004. Basic pharmacokinetics. London: Lippincott Williams
and Williams.
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Jelliffe equation:
Male: (98 - (0.8 * (age - 20)) / (SCR in mg/dL)) x Patient’s BSA/1.73 M2
Female: Multiply above result by 0.9
References:
Jelliffe RW. Estimation of creatinine clearance when urine cannot be
collected. Lancet 1971;1:975-6.
Jelliffe RW. Creatinine clearance: Bedside estimate. Ann Inter Med. 1973;
79:604.
Body Surface Area:
Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if
height and weight be known. Arch Intern Med. 1916; 17:863–71.
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