Irinotecan information from DrugsUpdate
P - Contraindicated in pregnancy
L - Contraindicated in lactation
Irinotecan (Camptosar, Pfizer; Campto, Yakult Honsha) is a drug used for the treatment of cancer.
Irinotecan is a topoisomerase 1 inhibitor, which prevents DNA from unwinding. Chemically, it is a semisynthetic analogue of the natural alkaloid camptothecin. Its main use is in colon cancer, particularly in combination with other chemotherapy agents. This includes the regimen FOLFIRI which consists of infusional 5-fluorouracil, leucovorin, and irinotecan. Irinotecan was approved by the U.S. Food and Drug Administration (FDA) in 1994. During development, it was known as CPT-11.
Pharmacodynamics
Pharmacokinetics
Irinotecan, a derivative of camptothecin, works by inhibiting the enzyme topoisomerase I thereby interfering with the coiling and uncoiling of DNA during replication and causing irreparable damage.
Distribution
Irinotecan is moderately bound to plasma albumin (approx 65%) and SN-38 is extensively bound (approx 95%).
Metabolism
Converted to active metabolite SN-38 via hydrolysis in the liver.
Excretion
Both biliary and urinary excretion. SN-38 primarily removed by glucuronidation. Elimination half life of 6-12 hours.
Irinotecan Indications / Irinotecan Uses
Information Not Available
Irinotecan Adverse Reactions / Irinotecan Side Effects
Neutropenia, anaemia, thrombocytopenia; acute diarrhoea, sweating, hypersalivation, abdominal cramps, lachrymation, miosis, weakness; nausea, vomiting, alopecia and skin reactions; cardiovascular toxicity.
Potentially Fatal: Fatal sepsis due to myelosuppression; severe, chronic diarrhoea.
Precautions
Warnings
Diarrhea
Irinotecan injection can induce early and late forms of diarrhea, which may be severe and appear to be mediated by different mechanisms. May be life-threatening.
Myelosuppression
Deaths caused by sepsis following severe myelosuppression have been reported in patients treated with irinotecan. Temporarily discontinue therapy if neutropenic fever occurs or if the absolute neutrophil count drops below 1,000/mm 3 .
Special Precautions
Previous pelvic/abdominal irradiation; elderly; Raised plasma-bilirubin concentration; severe myelosuppression. Avoid extravasation.
Other Drug Interactions
Diuretics increase risks of dehydration secondary to vomiting/diarrhoea; prophylactic dexamethasone as an antiemetic may enhance lymphocytopenia; prochlorperazine may increase incidence of akathisia; antineoplastic agents (myelosuppression and diarrhoea). St John's wort, ketoconazole may reduce irinotecan exposure.
Other Interactions
Information Not Available
Dosage
Intravenous
Refractory colorectal malignancies
Adult: 125 mg/m2 infused IV over 90 min once weekly for 4 weeks followed by a 2 weeks rest period. Or, 350 mg/m2 infused IV over 90 minutes repeated once every 3 weeks.
Hepatic impairment: Dose reduction may be necessary.
Intravenous
Metastatic colorectal cancer
Adult: As 1st line treatment: 125 mg/m2 infused IV over 90 min on days 1,8,15 and 22 of a 6 weeks cycle. Alternatively 180 mg/m2 infused IV over 90 min on days 1,15 and 29 of a 6 weeks cycle.
Hepatic impairment: Dose reduction may be necessary.
Reconstitution
Dilute in 5% dextrose injection (preferred) or 0.9% sodium chloride injection to a final concentration of 0.12-2.8 mg/ml.
Food(before/after)
Information Not Available
List of Contraindications
Irinotecan and Pregnancy
Contraindicated in pregnancy
Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).
Irinotecan and Lactation
Contraindicated in lactation
Irinotecan and Children
Safety and efficacy not established
Irinotecan and Geriatic
Exercise particular caution in monitoring the effects of irinotecan in the elderly (ie, 65 years of age and older).
Irinotecan and Other Contraindications
Inflammatory bowel disease, bowel obstruction, severe hepatic impairment. Pregnancy and lactation.
Storage
Information Not Available
Lab interference
Information Not Available
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