Irinotecan
Irinotecan is a chemotherapy medication classified as a topoisomerase I inhibitor used primarily to treat metastatic colorectal cancer. It works by binding to the topoisomerase I-DNA complex, preventing DNA relegation and causing irreversible DNA damage that leads to cancer cell death. It may be used as a single agent or in combination with other chemotherapy drugs.
Irinotecan is an antineoplastic agent used to treat metastatic colorectal cancer by inhibiting topoisomerase I and causing cancer cell death.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L01CE02
- RxNorm
- 51499
- Generic
- Irinotecan
- Class
- atc-l01
- Brands
- Onivyde, Camptosar
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks to the fetus
regular fetal monitoring via ultrasound
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring and growth assessments
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid if possible
avoid use near term due to risk of premature labor and fetal toxicity
fetal monitoring and uterine activity monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingdiscontinue breastfeeding
do not breastfeed during treatment and for at least 7 days after last dose
monitor infant for signs of toxicity
Use of this medication in this population requires careful consideration of risks and benefits.
geriatric
elderlyconsider starting at lower end of dosing range
monitor closely for adverse effects including diarrhea and myelosuppression
more frequent monitoring of blood counts and renal function
Use with caution and monitor for adverse effects.
pediatric_age
pediatricweight-based dosing with close monitoring
used for pediatric cancers including neuroblastoma and rhabdomyosarcoma; hydration and anti-diarrheal prophylaxis recommended
close monitoring of blood counts and fluid status
Use with caution and monitor for adverse effects.
renal_impairment
moderate to severereduce dose in severe impairment
dose reduction recommended for patients with creatinine clearance less than 30 mL/min
monitor renal function and adjust dose accordingly
Use with caution and monitor for adverse effects.
hepatic_impairment
hepatic impairmentreduce dose based on bilirubin levels
reduce starting dose for patients with bilirubin above 1.5 mg/dL; avoid use if bilirubin exceeds 3x ULN
monitor liver function tests and bilirubin levels closely
Use with caution and monitor for adverse effects.
Statistics and clinical data
Commonly prescribed since
FDA approval year for Camptosar
Drug class
Antineoplastic agent classification
Common uses
Primary therapeutic indications
Mechanism of action
Pharmacological mechanism
Metastatic colorectal cancer (first-line and second-line treatment), small cell lung cancer, and pancreatic cancer (in combination with other agents). May be used as part of FOLFIRI regimen (fluorouracil, leucovorin, and irinotecan).
Irinotecan is a camptothecin derivative that inhibits topoisomerase I, an enzyme that relieves torsional strain in DNA by inducing reversible single-strand breaks. By binding to the topoisomerase I-DNA complex, irinotecan and its active metabolite SN-38 prevent DNA relegation, causing irreversible double-strand breaks that lead to cell death (apoptosis).
Administered intravenously; requires regular monitoring of blood counts and liver function. Common side effects include severe diarrhea, nausea, vomiting, and myelosuppression. Premedication with anticholinergics may be needed for early-onset diarrhea. Contraindicated in patients with severe renal impairment or known hypersensitivity. Pregnancy category D - should not be used during pregnancy.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy