Carboplatin – Uses, Dosing, Administration, Side Effects

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Pharmacokinetics and Pharmacodynamics

  • cis-diammine-cyclobutanedicarboxylato-platinum
  • 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.

Administration

  • 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.

Toxicity

Dose-limiting

  • Myelosuppression
  • Increases with reduced creatinine clearance levels and with subsequent cycles

Common

  • Nausea and vomiting (less severe than with cisplatin, resolves in 24 hrs ),
  • Pain at injection site

Occasional

  • Abnormal LFTs,
  • Azotemia;
  • Neurotoxicity (5%) with dose > 600 mg/m2, features similar to cisplatin,
  • Hypersensitivity reactions ( > 6 cycles ),
  • Disorders in fertility

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