♦Carboplatin
(kar’-bo-pla-tin)
Paraplatin,
CBDCA
Pregnancy Category D
Mechanism of Action
Carboplatin is a cell cycle-nonspecific alkylating agent that prevents cell replication by producing intra- and inter-DNA cross-links.
Indications
Ovarian cancer (advanced) previously treated with other cyto-toxic agents, including cisplatin. Endometrial cancer, relapsed and refractory acute leukemia, metastatic seminoma, small cell lung cancer, squamous cell carcinoma of the head and neck.
Metabolism/Excretion
About 70% is excreted in the urine 24 hours after administration. Plasma half-life: 1.1 to 2.0 hours. Postdistribution half-life: 2.6 to 5.9 hours.
Dosage Range
Adult
♦ Single agent: 360 mg/m2 on day 1 given every 4 weeks. In general, the carboplatin dose should not be repeated until the neutrophil count is 2000/mm3 and the platelet count is ≥100,000/mm3.
♦ Combination with cyclophosphamide: 300 mg/m2 on day 1 IV every 4 weeks.
♦ Formula dosing: Another method for calculating the initial carboplatin dose is the use of a mathematical formula based on the pre-existing renal function and desired platelet nadir. This approach takes into account the pre-treatment renal function, which might be overlooked using the formula based on body surface. The formula, proposed by Calvert, is as follows:
Total dose (mg) = (target AUC) × (glomerular filtration rate + 25)
AUC (area under the curve) is obtained by plotting the plasma level of a drug over time and measuring the area beneath the plotted curve. Glomerular filtration rate has a good correlation to creatinine clearance. Therefore, this value is used in the calculation for carboplatin. The target area under the curve of 4 to 6 mg/mL/ min using carboplatin as a single agent is often used.