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Carboplatin AUC Calculator

Age:    Scr:     Gender:
Height     Weight:
Target AUC  (mg/ml/min)
Is this a previously treated patient? :
Is the serum creatinine (Scr) currently stable:  
Restrict the maximum calculated clearance to this value

Background Info

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

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)]

Alternative equation:
ABW (kg) = ideal body weight + [0.3 * (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.

Disclaimer

All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgement. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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