Irinotecan: uses, dosing, side effects & brands
Irinotecan is a topoisomerase inhibitor sold in the U.S. under 3 brand and generic names, for breast neoplasms, non-small-cell lung carcinoma and colonic neoplasms. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Topoisomerase Inhibitor
- Treats (across its forms)
- Breast Neoplasms, Non-Small-Cell Lung Carcinoma and Colonic Neoplasms
- Available as
- Injectable · Solution
- Sold as
- 3 products — Camptosar, Irinotecan Hydrochloride and Onivyde
- Prescription?
- Prescription only
- Generic available?
- Yes
- Boxed warning
- Boxed warning
How Camptosar is dosed
From the FDA label for Camptosar (application NDA020571). Other irinotecan products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Colorectal cancer combination regimen 1: CAMPTOSAR 125 mg/m 2 intravenous infusion over 90 minutes on days 1, 8,15, 22 with LV 20 mg/m 2 intravenous bolus infusion on days 1, 8, 15, 22 followed by 5-FU intravenous bolus infusion on days 1, 8, 15, 22 every 6 weeks. ( 2.1 ) • Colorectal cancer combination regimen 2: CAMPTOSAR 180 mg/m 2 intravenous infusion over 90 minutes on days 1, 15, 29 with LV 200 mg/m 2 intravenous infusion over 2 hours on days 1, 2, 15, 16, 29, 30 followed by 5-FU 400 mg/m 2 intravenous bolus infusion on days 1, 2, 15, 16, 29, 30 and 5-FU 600 mg/m 2 intravenous infusion over 22 hours on days 1, 2, 15, 16, 29, 30. ( 2.1 ) • Colorectal cancer single agent regimen 1: CAMPTOSAR 125 mg/m 2 intravenous infusion over 90 minutes on days 1, 8, 15, 22 then 2-week rest. ( 2.2 ) • Colorectal cancer single agent regimen 2: CAMPTOSAR 350 mg/m 2 intravenous infusion over 90 minutes on day 1 every 3 weeks. ( 2.2 ) 2.1 Colorectal Cancer Combination Regimens 1 and 2 Administer CAMPTOSAR as a 90-minute intravenous infusion followed by LV and 5-FU. The currently recommended regimens are shown in Table 1. A reduction in the starting dose by one dose level of CAMPTOSAR may be considered for patients with any of the following conditions: prior pelvic/abdominal radiotherapy, performance status of 2, or increased bilirubin levels. Dosing for patients with bilirubin >2 mg/dL…
Everything below is the FDA label for Camptosar (injectable). Irinotecan is also sold as solution, and those are different medicines to take — follow the label for the one you were prescribed.
Camptosar side effects
Common adverse reactions (≥30%) observed in combination therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, mucositis, neutropenia, leukopenia (including lymphocytopenia), anemia, thrombocytopenia, asthenia, pain, fever, infection, abnormal bilirubin, alopecia. ( 6.1 ) Common adverse reactions (≥30%) observed in single agent therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, neutropenia, leukopenia (including lymphocytopenia), anemia, asthenia, fever, body weight decreasing, alopecia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc, at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Common adverse reactions (≥30%) observed in combination therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, mucositis, neutropenia, leukopenia (including lymphocytopenia), anemia, thrombocytopenia, asthenia, pain, fever, infection, abnormal bilirubin, and alopecia. Common adverse reactions (≥30%) observed in single agent…
Who shouldn’t take Camptosar
CAMPTOSAR Injection is contraindicated in patients with a known hypersensitivity to the drug or its excipients. • Hypersensitivity to CAMPTOSAR or its excipients ( 4 )
Camptosar drug interactions
Strong CYP3A4 Inducers: Do not administer strong CYP3A4 inducers with CAMPTOSAR. ( 7.2 ) • Strong CYP3A4 Inhibitors: Do not administer strong CYP3A4 inhibitors with CAMPTOSAR. ( 7.3 ) 7.1 5-Fluorouracil (5-FU) and Leucovorin (LV) In a phase 1 clinical study involving irinotecan, 5-fluorouracil (5-FU), and leucovorin (LV) in 26 patients with solid tumors, the disposition of irinotecan was not substantially altered when the drugs were co-administered. Although the C max and AUC 0–24 of SN-38, the active metabolite, were reduced (by 14% and 8%, respectively) when irinotecan was followed by 5-FU and LV administration compared with when irinotecan was given alone, this sequence of administration was used in the combination trials and is recommended [see Dosage and Administration (2) ] . Formal in vivo or in vitro drug interaction studies to evaluate the influence of irinotecan on the disposition of 5-FU and LV have not been conducted. 7.2 Strong CYP3A4 Inducers Exposure to irinotecan or its active metabolite SN-38 is substantially reduced in adult and pediatric patients concomitantly receiving the CYP3A4 enzyme-inducing anticonvulsants phenytoin, phenobarbital, carbamazepine, or St. John's wort. The appropriate starting dose for patients taking these or other strong inducers such as rifampin and rifabutin has not been defined. Consider substituting non-enzyme inducing therapies at least 2 weeks prior to initiation of CAMPTOSAR therapy. Do not administer strong CYP3A4 inducers with CAMPTOSAR unless there are no therapeutic alternatives. 7.3 Strong CYP3A4 or UGT1A1 Inhibitors Irinotecan and its active metabolite, SN-38, are metabolized via the human cytochrome P450 3A4 isoenzyme (CYP3A4) and uridine diphosphate-glucuronosyl transferase 1A1 (UGT1A1), respectively, [see Clinical Pharmacology (12.3) ] . Patients receiving concomitant ketoconazole, a CYP3A4 and UGT1A1 inhibitor, have increased exposure to irinotecan and its active metabolite SN-38. Coadministration of CAMPTOSAR with other inhibitors of CYP3A4 (e.g., clarithromycin, indinavir, itraconazole, lopinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telaprevir, voriconazole) or UGT1A1 (e.g., atazanavir, gemfibrozil, indinavir) may increase systemic exposure to irinotecan or SN-38. Discontinue strong CYP3A4 inhibitors at least 1 week prior to starting CAMPTOSAR therapy. Do not administer strong CYP3A4 or UGT1A1 inhibitors with CAMPTOSAR unless there are no therapeutic alternatives.
Every irinotecan product we track (3)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 64/100 | Prescription | Injectable | No data | — | View → | |
| 2 | Not yet rated | Prescription | Injectable | No data | — | View → | |
| 3 | Not yet rated | Prescription | Injectable | No data | — | View → |
How long irinotecan keeps
The date on a sealed pack is not the only one: some irinotecan labels start a second clock once the product is opened or mixed, as short as 4 hours.
Does irinotecan expire? The in-use limits and storage rules from its labelsIrinotecan and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for irinotecan: levels in milk, effects in breastfed infants, and the drugs it would consider insteadLimited data indicate that irinotecan is found in breastmilk for 2 days and its active metabolite is found in breastmilk for up to a week after a dose of 60 mg/square meter, although the highest amounts occur during the first 4 days after a dose. Higher maternal doses have not been studied and the oral absorption and toxicity in breastfed infants are not known. Based on this limited evidence, it appears that breastfeeding should be avoided for at least a week after a dose of irinotecan 60 mg/square meter. Higher dosages probably require a longer abstinence period. Some authors recommend discontinuing breastfeeding during irinotecan therapy. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk. Women who receive chemotherapy during pregnancy are more likely to have difficulty nursing their infant.
National Institute of Child Health and Human Development, record revised January 15, 2025. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about irinotecan
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 7,993 reports naming irinotecan, and the FDA flagged 96% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- diarrhoea890 reports
- myelosuppression652 reports
- nausea501 reports
- febrile neutropenia475 reports
- vomiting431 reports
- neutropenia423 reports
- neuropathy peripheral351 reports
- neoplasm progression323 reports
Read these as a signal, not a rate. A report does not mean irinotecan caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
Related calculators
Frequently asked questions
What is Camptosar?
Injection (irinotecan hydrochloride injection) is an antineoplastic agent of the topoisomerase I inhibitor class. CAMPTOSAR is supplied as a sterile, pale yellow, clear, aqueous solution.
What kind of drug is irinotecan?
The FDA classifies irinotecan as a topoisomerase inhibitor. Topoisomerase inhibitors target enzymes that cells rely on to cut and rejoin their DNA during cell division. By trapping these enzymes after they cut the DNA but before they can reseal it, the drugs leave the DNA broken, which halts cell division and kills rapidly dividing cancer cells. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take irinotecan with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run irinotecan against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is irinotecan sold under?
We track 3 irinotecan-containing products in the U.S.: Camptosar, Irinotecan Hydrochloride and Onivyde. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does irinotecan come in?
Across the brands we track, irinotecan is currently marketed as injectable and solution, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic irinotecan?
Yes. Our catalog lists 1 generic irinotecan product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Cite this page
- APA
- pharmaranks. (2026, July 24). Irinotecan: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/irinotecan
- MLA
- “Irinotecan: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/irinotecan.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for irinotecan on DailyMed (NIH) ↗ — including its boxed warning in full.