Chemotherapy

 

 

Camptothecins

 

CLASS OF DRUG

PLANT DERIVATION

EXAMPLE

CAMPTOTHECINS

Chinese plant Camptotheca acuminate.

Irinotecan

Topotecan

 

Derived from the Chinese plant Camptotheca acuminate.

Two of its analogues are irinotecan and topotecan.

All camptothecins target Topoisomerase I and are cell cycle specific acting in the S phase.

Resistance mechanisms are via down-regulation of topoisomerase I and MDR gene expression.

 

Irinotecan

  • Can be used in the treatment of rhabdomyosarcoma.
  • Given IV

 

Topotecan

  • Given IV in adults as a second line agent in advanced ovarian cancer and refractory small-cell lung cancer, and for the treatment of haematological malignancies.
  • Also being considered in the treatment of pediatric solid tumours, such as rhabdomyosarcoma and neuroblastoma.
  • Reversible, non-cumulative myelosuppression, alopecia and gastrointestinal disturbances are its most common toxicities.
  • Given IV.  Intrathecal administration is being studied for the treatment of neoplastic meningitis.

 

Summary of Toxicities:

Drug

Toxicity

Special considerations

Irinotecan

Neutropenia, anemia (nadir is dose and schedule dependent)

 

Diarrhea (early or late onset)

 

GI disturbances (nausea, vomiting, anorexia, abdominal pain)
  • May require medication to control diarrhea (atropine for early, loperamide for late)
  • Patients with severe diarrhea should be monitored for dehydration and given fluid and electrolyte replacement as needed
  • Teach family parameters for when to call health care provider for increased stools. Patients should be instructed to have antidiarrheals on hand and to start treatment at the first sign of diarrhea

Topotecan

Myelosuppression (nadir 12-15 days)

 

Alopecia

 

GI disturbances (nausea, vomiting, anorexia, diarrhea, constipation)

  • IT doses should be administered over 5 minutes to avoid potential adverse reactions

 

 

 

 

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