Pharmacokinetics and Pharmacodynamics
- t1/2 = 12 – 24 min; t1/2 = 1.3 – 1.7 hr; t1/2 = 22 – 40 hr
- 24% Plasma Protein Binding (PPB) at 4 hours infusion
- 90% is excreted in the urine in 24 hr
Cancer Types where Carboplatin is used (Indications)
- Ovarian cancer
- Germ cell tumors
- Head and neck cancer
- Small cell and non–small cell lung cancer
- Bladder cancer
- Relapsed and refractory lymphoma
- Endometrial cancer
- Cervical cancer
Cisplatin vs Carboplatin
- Carboplatin can replace cisplatin in the treatment of ovarian cancer and lung cancer
- Carboplatin is inferior to cisplatin in germ cell, head and neck, gastric and esophageal cancers
- Not known whether it has equivalent efficacy to cisplatin in bladder, cervical, and endometrial cancers
Availability and Dosing
- Available as 50, 150, 450 mg vials
- Dosing of carboplatin is calculated based on glomerular filtration rate. The formula used for it is called as Calvert’s Formula.
- The AUC dose is calculated using the Calvert formula
Carboplatin dose = target AUC * (GFR + 25)
Why AUC is used to calculate dosing?
- A close relationship of changes in platelet counts, response and neutropenia to AUC.
- AUC is related to the renal function.
- AUC of 5-7 is used as response increases with the increase in the AUC upto this level, and plateaus beyond this dose.
- Unit – mg/ ml/ min.
- The value of 25 ml/min is a constant that used to correct for the nonrenal clearance of irreversibly tissue-bound carboplatin.
- In NS or 5% Dextrose
- Duration of administration is usually 1 to 4 hours.
- The 1-hour time frame is the most common.
- Much less renal toxicity than cisplatin, hence no need for vigorous hydration or forced diuresis.
- Increases with reduced creatinine clearance levels and with subsequent cycles
- Nausea and vomiting (less severe than with cisplatin, resolves in 24 hrs ),
- Pain at injection site
- Abnormal LFTs,
- Neurotoxicity (5%) with dose > 600 mg/m2, features similar to cisplatin,
- Hypersensitivity reactions ( > 6 cycles ),
- Disorders in fertility