irinotecan

Trade Name:

Camptosar®

Other Names:

Camptosar®

Synonym:

CPT-11

Appearance:

Clear, light-yellow solution mixed into larger bags of fluids

Monograph Name:

irinotecan

Monograph Body:

Drug Monograph

A - Drug Name

irinotecan

SYNONYM(S): CPT-11

COMMON TRADE NAME(S): Camptosar®

B - Mechanism of Action and Pharmacokinetics

Irinotecan is a semi-synthetic derivative of camptothecin, an alkaloid extract from camptotheca acuminata. Camptothecin and its analogue belong to the class of topoisomerase I inhibitors. Irinotecan and its active metabolite, SN-38, bind to the topoisomerase DNA complex, preventing religation of the single-strand breaks in the DNA molecule. The drug and its active metabolite are believed to exert their cytotoxic effects during the S-phase of cell cycle.

Distribution

Peak plasma concentrations of irinotecan are reached by the end of intravenous infusion, whereas those of the SN-38 metabolite occur about 0.5 to 2 hours after the infusion period. Irinotecan exposure increased in a dose-dependent manner over the usual range, where SN-38 increases less than proportionally with dose. No impact of gender on pharmacokinetics.

Cross blood brain barrier?

No information found

PPB

30–68% (irinotecan);
95% (SN-38) (mainly albumin)

Metabolism

Irinotecan is metabolized to its active form, SN38, in the presence of hepatic or gastrointestinal carboxylesterase. Both irinotecan and SN-38 undergo pH-dependent, reversible hydrolysis from the active closed-ring lactone to an open inactive carboxylate form. Irinotecan is also metabolized in part by CYP3A4 and UGT1A1 to inactive metabolites.

Active metabolites

SN-38

Inactive metabolites

yes

Elimination

The complete disposition of irinotecan in human has not been fully elucidated. SN-38 subsequently undergoes conjugation (by UDP glucuronyl transferase – UGT1A1) to form a glucuronide metabolite and is excreted in bile. Approximately 10% of the North American population is homozygous for the wild-type UGT1A1*28 allele, which results in reductions in UGT1A1 enzyme activity and higher SN38 systemic exposure.

Urine

Low (11-20% unchanged, 5% as metabolites)

Half-life

5.8-11.7 h (irinotecan); 7.7-17 h (SN38)

C - Indications and Status

Health Canada Approvals:

Single-agent treatment for recurrent colorectal cancer after treatment with fluorouracil-based chemotherapy
As a component of combination first-line chemotherapy for patients with metastatic colorectal cancer

Other Uses:

Gastrointestinal cancer (gastric, pancreatic, small bowel and appendix)
Ewing's sarcoma
Small cell lung cancer

D - Adverse Effects

Emetogenic Potential:

Moderate

Extravasation Potential: None

The adverse effects listed below were reported in > 10% of patients from 3 pooled clinical trials of single-agent, weekly irinotecan in previously treated metastatic colorectal cancer and includes severe or life-threatening events (from these trials or other sources).

ORGAN SITE	SIDE EFFECT* (%)	ONSET**
Cardiovascular	Bradycardia (during infusion)	I
	Hypotension (rare)	E
	Thromboembolism (5%)	E
Dermatological	Alopecia (61%)	E
	Rash (13%)	E
Gastrointestinal	Abdominal pain (57%) (severe 16%)	I E
	Anorexia, weight loss (55%)	I E
	Constipation (30%)	E
	Diarrhea (51%) (early; late 88%, severe 31%)	I E
	Dyspepsia (11%)	E
	Flatulence (12%)	E
	GI obstruction (rare)	E
	GI perforation (rare)	E
	Mucositis (12%)	E
	Nausea, vomiting (86%) (severe 17%)	I E
General	Edema (10%)	E
	Fatigue (76%) (severe 12%)	I
	Other (28%) (cholinergic symptoms)	I
Hematological	Myelosuppression ± infection, bleeding (28%) (grade 3/4)	E
Hepatobiliary	↑ LFTs (13%) (4% severe)	E
	Pancreatitis (rare)	E
Hypersensitivity	Hypersensitivity (rare)	I
Metabolic / Endocrine	Hyperglycemia (uncommon)	E
	Tumour lysis syndrome (rare)	I
Musculoskeletal	Musculoskeletal pain (15%)	E
Nervous System	Dizziness (15%)	I E
	Dysarthria (or speech disorder; rare, transient)	I
	Headache (17%)	I E
	Insomnia (19%)	I E
Renal	Renal failure (rare)	E
Respiratory	Cough, dyspnea (22%)	I E
	Pneumonitis (infrequent)	I E
	Rhinitis (16%)	I E
Vascular	Flushing (11%)	I

* "Incidence" may refer to an absolute value or the higher value from a reported range.
"Rare" may refer to events with < 1% incidence, reported in post-marketing, phase 1 studies,
isolated data or anecdotal reports.

** I = immediate (onset in hours to days) E = early (days to weeks)
D = delayed (weeks to months) L = late (months to years)

The most common side effects for irinotecan include nausea, vomiting, fatigue, alopecia, abdominal pain, anorexia, weight loss, diarrhea, constipation, myelosuppression ± infection, bleeding and cholinergic symptoms.

The most common and severe adverse effect of irinotecan is diarrhea. Two distinct types of diarrhea associated with irinotecan have been identified – an early onset cholinergic syndrome and late-onset diarrhea. The early-onset cholinergic effects, usually transient, may arise up to 24 hours after treatment and includes profound warmth, rhinitis, lacrimation, increased salivation, diaphoresis or flushing, followed by abdominal cramping and sudden diarrhea. They are thought to be related to the anticholinesterase activity of irinotecan and are more likely to occur at higher dose levels. Acute events are managed successfully by administering IV or SC atropine 0.25 to 1 mg. Because of the short half-life of atropine, using it to prevent cholinergic symptoms is controversial; however, prophylactic atropine should be considered (unless contraindicated) in patients experiencing cholinergic symptoms.

Late diarrhea (occurring more than 24 hours after administration) may lead to dehydration or electrolyte imbalances, and can be life-threatening. The mechanism of late onset diarrhea is not well understood, but it appears to be linked to a secretory process that may be a secondary consequence of an irinotecan cytotoxic effect on the GI mucosa. It occurs in 80% of patients and the median onset time is 5-11 days, depending on the irinotecan dosing schedule. Late diarrhea must be treated promptly with loperamide, 4 mg at the first onset of late diarrhea and then 2mg every 2 hours until the patient is diarrhea-free for at least 12 hours. During the night the patient may take 4mg of loperamide every 4 hours. At these doses, loperamide is not recommended to be used for more than 48 consecutive hours due to the risk of paralytic ileus. Fluid intake should be maintained to avoid dehydration. Premedication with loperamide is not recommended and laxatives should be avoided. Antibiotics should be used in patients with ileus, fever or severe neutropenia.

Irinotecan-induced neutropenia is dose-related, generally brief, and non-cumulative, with a typical onset between days 15 and 21 and recovery between days 28 and 35. The frequency of grade 3 or 4 neutropenia is higher in patients who had prior pelvic or abdominal irradiation, had elevated serum bilirubin or who received the drug over less than 90 minutes. Consider the use of G-CSF in patients experiencing severe neutropenia. An increased risk of neutropenia was observed in patients homozygous for the UGT1A1*28 allele. Consider reducing the irinotecan starting dose (appropriate dose not established) in these patients and those with a history of myelosuppression with previous treatment.

Pneumonitis has been reported infrequently (predominantly in studies from Japan) following administration of irinotecan. This has been described as dyspnea, a non-productive cough, or a diffuse pulmonary infiltrate on chest x-ray. The etiology of these problems is unknown, and it is not clear whether they truly are caused by irinotecan or are actually a manifestation of the disease, primary lung cancer, or lung metastases.

Speech disorders (e.g. dysarthria, stuttering, voice changed) have been reported in post-marketing of irinotecan, with most cases occurring during or shortly after the irinotecan infusion and resolved spontaneously within minutes to hours. The cause of these speech disorders appeared to be unknown; some cases occurred with other neurologic, cholinergic or hypersensitivity symptoms.

E - Dosing

Refer to protocol by which the patient is being treated.

Screen for hepatitis B virus in all cancer patients starting systemic treatment. Refer to the hepatitis B virus screening and management guideline.

Adequate antiemetic therapy and prophylactic loperamide must be provided.

Patients should not be treated with irinotecan until they have recovered from prior toxicity: platelets ≥ 100 x 10⁹/L, ANC ≥ 1.5 x 10⁹/L, GI toxicity recovered to baseline (without loperamide for at least 24 hours) and all other toxicities to Grade ≤ 1.

Patients with ileus, fever or febrile neutropenia should receive antibiotics.

Consider a reduction in the starting dose described below for:

elderly patients (≥ 70 years)
patients with prior abdominal or pelvic irradiation
patients with a poor performance status (ECOG of 2)
patients with mild increases in bilirubin (including Gilbert's syndrome)
patients homozygous for UGT1A1*28 allele or patients with a history of myelosuppression with previous treatment

For cholinergic adverse effects (early diarrhea):

Prophylactic atropine may be considered in patients who have experienced cholinergic symptoms
Diarrhea (including abdominal cramps) may be severe and delayed with irinotecan; use loperamide 4mg at the onset of diarrhea, then 2mg every 2 hours until patient is diarrhea-free for 12 hours. During the night the patient may take 4mg of loperamide every 4 hours

Adults:

Single agent:

q1w:   125 mg/m² weekly for 4 weeks with a 2 week rest period.
            Dose may be increased to 150mg/m² in the absence of toxicity.

q3w:   ≥ 70 years:    300mg/m²
            < 70 years:   350mg/m²

In combination with 5-fluorouracil and leucovorin:

q2w: 180 mg/m² (See FOLFIRI regimen)
6-week regimen: 125mg/m² D1, 8, 15 ,22 (IFL regimen)

Dosage with Toxicity:

All dose adjustments should be based on the worst preceding toxicity.

Single Agent:

Dose Level	Dose (mg/m²)
	Weekly Regimen	Q 3 Weeks Regimen
0	125	350
-1	100	300
-2	75	250
-3	50	200

Toxicity grade³	Suggested dose During treatment course of Weekly schedule²	At start of subsequent course¹
Toxicity grade³		Weekly schedule²	3-weekly schedule²
1	No change	No change	No change
2	↓ 25mg/m²	Diarrhea alone – no change	Diarrhea alone – no change
		Hematologic alone – no change	Hematologic alone – no change
		Other ³ : ↓ 25mg/m²	Other ³: ↓ 50mg/m²
3	Omit, then ↓ 25mg/m² when ≤ grade 2	↓ 25mg/m²	↓ 50mg/m²
4 or febrile neutropenia	Omit, then ↓ 50mg/m² when ≤ grade 2	↓ 50mg/m²	↓ 50mg/m²
Pneumonitis	Hold; investigate and if confirmed, discontinue.
_{¹ Relative to the starting dose used in the previous cycle. Start new cycle when the parameters below are met. ²Patients should not be retreated until GI toxicity resolved to baseline (without loperamide for at least 24 h), platelets ≥ 100 x 10⁹/L, ANC ≥ 1.5 x 10⁹/L and other toxicities recovered to ≤ grade 1. If no recovery after a 2-week delay, consider discontinuing treatment.} _{³ Excludes alopecia, anorexia, and fatigue}

In Combination Treatment:

Dose Levels:

Regimen	Drug	Starting dose (mg/m²)	Dose level -1 (mg/m²)	Dose Level -2 (mg/m²)
FOLFIRI	Irinotecan	180	150	120
	Leucovorin infusion	400or 200^#	No change	No change
	5-FU bolus	400	320	240
	5-FU infusion* (start day 1 over 46 h)	2400	2000	1600
	Alternative schedule for 5-FU infusion (over 22 h on days 1 and 2)	600	480	360
IFL	Irinotecan	125	100	75
	Leucovorin bolus	20	20	20
	5-FU bolus	500	400	300

_{*This 5-FU infusion dosing has not been approved by Health Canada, but was used in some phase III trials.}
_{# Dose depends on regimen used.}

Dose Adjustments for Irinotecan in Combination with Fluorouracil:

Toxicity Grade		During a Cycle of Therapy² (IFL)	At the start of subsequent cycles^{1, 2}(IFL or FOLFIRI)
Hematologic
Grade 1		No change	No change
Grade 2		↓ by 1 dose level	No change
Grade 3		Omit until ≤ grade 2 , then ↓ by 1 dose level	↓ by 1 dose level
Grade 4 or febrile neutropenia		Omit until ≤ grade 2 , then ↓ by 2 dose levels	↓ by 2 dose levels
Diarrhea
Grade 1: 2-3/day > pre-treatment		Delay until recovery to baseline then give same dose	No change
Grade 2: 4-6/day > pre-treatment		Omit until recovery to baseline then ↓ by 1 dose level	No change
Grade 3: 7-9/day > pre-treatment		Omit until recovery to baseline then ↓ by 1 dose level	↓ by 1 dose level
Grade 4: ≥ 10/day > pre-treatment		Omit until recovery to baseline then ↓ by 2 dose levels	↓ by 2 dose levels
Other Non-hematologic toxicities (excludes alopecia, anorexia and fatigue). For mucositis/stomatitis, decrease 5FU only, not irinotecan.
Grade 1	No change		No change
Grade 2	Omit until ≤ grade 1, then ↓ by 1 dose level		No change
Grade 3	Omit until ≤ grade 2, then ↓ by 1 dose level		↓ by 1 dose level
Grade 4	Omit until ≤ grade 2, then ↓ by 2 dose levels		↓ by 2 dose levels
_{¹ Relative to the starting dose used in the previous cycle. Start new cycle when the parameters below are met.} ^₂_{Patients should not be retreated until GI toxicity resolved to baseline (without loperamide for at least 24 h), platelets ≥ 100 x 10⁹/L, ANC ≥ 1.5 x 10⁹/L and other toxicities recovered to ≤ grade 1. If no recovery after a 2-week delay, consider discontinuing treatment.}

Dosage with Hepatic Impairment:

Elimination is decreased in hepatic impairment with increased exposure to SN-38. Patients with bilirubin 1-1.5 x ULN or Gilbert’s syndrome are at an increased risk of myelosuppression.

Bilirubin ¹		Transaminases	Irinotecan dose
22-35 µmoL/L (1-1.5 x ULN) or with Gilbert’s syndrome			Monitor closely; may consider dose reduction
> 35 µmoL/L	or	>3 x ULN (without liver metastases) or >5 x ULN (with liver metastases)	Not recommended.
¹Consider investigating for reversible causes such as biliary obstruction and re-evaluate after stent

Dosage with Renal Impairment:

No specific studies, but as the kidney is not a major route of excretion, no adjustment anticipated to be required.

Dosage in the elderly:

Monitor patients ≥ 65 years closely for increased risk of diarrhea. Patients ≥ 70 years of age using the q3w schedule should receive 300mg/m² or 100 mg/m² if using weekly dosing.

Children:

Safety and efficacy not established.

F - Administration Guidelines

Mix in 500mL bag (D5W-preferred or NS) in a concentration range between 0.12 to 3 mg/mL; infuse IV over 90 minutes
Do not refrigerate admixtures in NS (may result in precipitation)
Avoid freezing irinotecan and its admixtures since this may result in drug precipitation
Do not admix with other drugs
Protect from light
Prior to the initial irinotecan treatment, patients should be given a sufficient supply of loperamide and instructed on its appropriate use
Avoid grapefruit, starfruit, Seville oranges, their juices or products during irinotecan treatment

G - Special Precautions

Contraindications:

Patients with a known hypersensitivity to the product or any of its ingredients
Irinotecan should not be co-administered with azole antifungals (ketoconazole etc, see Interactions section)
Avoid in patients with hereditary fructose intolerance since the product contains sorbitol
Avoid the use of live or live attenuated vaccines

Other Warnings/Precautions:

Not recommended for use in patients with ECOG performance status 3 or 4, or in patients with moderate or severe increases in bilirubin.
Carefully monitor and consider dose reduction for elderly patients, patients with poor performance status (= 2), limited marrow reserve, 3rd space accumulation, Gilbert’s syndrome and patients with reduced UGT1A1 activity; they may be more susceptible to the toxic effects of irinotecan.
Concurrent administration of irinotecan with irradiation is not recommended. Patients with prior pelvic or abdominal irradiation are at an increased risk of severe myelosuppression following irinotecan therapy.

Other Drug Properties:

Carcinogenicity: Unknown
The long-term carcinogenic potential of irinotecan has not been studied.

Pregnancy and Lactation:

Embryotoxicity: Yes
Teratogenicity: Yes
Pregnancy:

Irinotecan is not recommended for use in pregnancy.
- Adequate contraception should be used by patients who can become pregnant and their partners during treatment, and for 6 months after the last dose.
- Adequate contraception should be used by patients who produce sperm and their partners during treatment, and for 3 months after the last dose.
Excretion into breast milk: Documented in animals

Breastfeeding is not recommended during treatment and for 7 days after the last dose.
Fertility effects: Unknown

H - Interactions

AGENT	EFFECT	MECHANISM	MANAGEMENT
Dexamethasone	Lymphocytopenia	Additive	Monitor blood count
Dexamethasone	Hyperglycemia (especially in patients with glucose intolerance)	Lowers glucose tolerance	Monitor blood glucose
Prochlorperazine	↑ akathisia observed when given on same day as irinotecan weekly	Unknown	Caution; avoid on same day of irinotecan treatment
Diuretics	↑ dehydration	Additive	Monitor or Avoid
Azole antifungals	↑ irinotecan toxicity	↑ exposure of SN38 (110%)	CONTRAINDICATED. (Discontinue ≥ 1 week before first dose of irinotecan)
Other inhibitors of CYP3A4 (ciprofloxacin, clarithromycin, verapamil, grapefruit juice, etc)	↑ irinotecan toxicity	↑ exposure; increased formation of SN38	Avoid concomitant use or adjust irinotecan dose
CYP3A4 inducers (i.e. phenytoin, rifampin, dexamethasone, carbamazepine, phenobarbital, St. John’s Wort, etc)	↓ irinotecan effects	↓ exposure because of lower SN38 levels	Avoid concomitant use – switch to non-enzyme inducing anticonvulsants; discontinue St. John's Wort ≥ 1 week prior to irinotecan.
Curcumin (tumeric)	may reduce effect of irinotecan	inhibits Irinotecan induced apoptosis	Avoid concomitant use
Atazanavir	↑ effect of irinotecan	inhibits UGT1A1 and CYP3A4	Avoid concomitant use
Bevacizumab	Unclear. Potential increased toxicity of irinotecan	Some pharmacokinetic studies have suggested ↑ SN38 levels with coadministration of bevacizumab	Caution
Neuromuscular blocking agents (ie. suxamethonium, succinylcholine)	Prolonged neuromuscular blocking effects	Additive anticholinesterase activity	Caution
UGT1A1 inhibitors (i.e. sorafenib, protease inhibitors)	↑ effect of irinotecan	Inhibition of UGT1A1 (up to 120% ↑ exposure in SN-38)	Caution. Monitor for signs and symptoms of irinotecan toxicity.
laxatives	Worsens diarrhea	Additive	Avoid

I - Recommended Clinical Monitoring

Treating physicians may decide to monitor more or less frequently for individual patients but should always consider recommendations from the product monograph.

Refer to the hepatitis B virus screening and management guideline for monitoring during and after treatment.

Recommended Clinical Monitoring

Monitor Type	Monitor Frequency
CBC	Baseline and before each dose
Liver function tests	Baseline and before each cycle (q 3 week regimen) or monthly (weekly x 4 regimen)
Toxicity rating of diarrhea and other GI effects, cholinergic symptoms, pneumonitis, neurological, bleeding, infection, dehydration, fatigue, pancreatitis, thromboembolism	At each visit

Grade toxicity using the current NCI-CTCAE (Common Terminology Criteria for Adverse Events) version

Suggested Clinical Monitoring

Monitor Type	Monitor Frequency
Renal function tests	Periodic
Blood glucose, especially in patients with diabetes	Baseline and as clinically indicated

K - References

Berg D. Irinotecan Hydrochloride: drug profile and nursing implications of a topoisomerase I inhibitor in patients with advanced colorectal cancer. ONF 1998;25(3):535-43.

Drengler RL, Kuhn JG, Schaaf LJ et al. Phase I and pharmacokinetic trial of oral irinotecan administered daily for 5 days every 3 weeks in patients with solid tumor. J Clin Oncol 1999: 17(2):685-96.

Irinotecan. Lexicomp Online, Lexi-Drugs Online, Hudson, Ohio: Wolters Kluwer Clinical Drug Information, Inc.; 2018; October 26, 2018

McEvoy GK, editor. AHFS Drug Information 2013. Bethesda: American Society of Health-System Pharmacists, p. 1089-93.

Product Monograph: Avastin® (bevacizumab). Hoffmann-La Roche Ltd., February 23, 2012.

Product Monograph: Camptosar® (irinotecan). Pfizer Canada Inc., December 9, 2014.

Product Monograph: Irinotecan. Pfizer Canada Inc., February 11, 2015 and September 14, 2022.

Product Monograph: Nexavar® (sorafenib). Bayer Inc., May 1, 2013.

Somasundaram S, Edmund NA, Moore DT, Small GW, Shi YY, Orlowski RZ. Dietary curcumin inhibits chemotherapy-induced apoptosis in models of human breast cancer. Cancer Res 2002 Jul 1;62(13):3868-75.

Tournigand C, André T, Achile E, et al. FOLFIRI followed by FOLFOX6 or the reverse sequence in advanced colorectal cancer: a randomized GERCOR study. J Clin Oncol 2004;22(2):229-37.

Wiseman LR, Markham A. Irinotecan: a review of its pharmacological properties and clinical efficacy in the management of advanced colorectal cancer. Drugs 1996;52(4):606-23.

August 2025 Updated Pregnancy/Lactation section

L - Disclaimer

Refer to the New Drug Funding Program or Ontario Public Drug Programs websites for the most up-to-date public funding information.
The information set out in the drug monographs, regimen monographs, appendices and symptom management information (for health professionals) contained in the Drug Formulary (the "Formulary") is intended for healthcare providers and is to be used for informational purposes only. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects of a particular drug, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for a given condition. The information in the Formulary is not intended to constitute or be a substitute for medical advice and should not be relied upon in any such regard. All uses of the Formulary are subject to clinical judgment and actual prescribing patterns may not follow the information provided in the Formulary.
The format and content of the drug monographs, regimen monographs, appendices and symptom management information contained in the Formulary will change as they are reviewed and revised on a periodic basis. The date of last revision will be visible on each page of the monograph and regimen. Since standards of usage are constantly evolving, it is advised that the Formulary not be used as the sole source of information. It is strongly recommended that original references or product monograph be consulted prior to using a chemotherapy regimen for the first time.
Some Formulary documents, such as the medication information sheets, regimen information sheets and symptom management information (for patients), are intended for patients. Patients should always consult with their healthcare provider if they have questions regarding any information set out in the Formulary documents.
While care has been taken in the preparation of the information contained in the Formulary, such information is provided on an “as-is” basis, without any representation, warranty, or condition, whether express, or implied, statutory or otherwise, as to the information’s quality, accuracy, currency, completeness, or reliability.
CCO and the Formulary’s content providers shall have no liability, whether direct, indirect, consequential, contingent, special, or incidental, related to or arising from the information in the Formulary or its use thereof, whether based on breach of contract or tort (including negligence), and even if advised of the possibility thereof. Anyone using the information in the Formulary does so at his or her own risk, and by using such information, agrees to indemnify CCO and its content providers from any and all liability, loss, damages, costs and expenses (including legal fees and expenses) arising from such person’s use of the information in the Formulary.

Info Sheet Name:

irinotecan (patient)

Info Sheet Introduction:

For treating cancer of the colon, rectum or other cancers

Info Sheet Date: Thursday, August 21, 2025 Info Sheet body:

irinotecan

Pronunciation:

eye-reen-oh-TEE-can

Other Name(s):

Camptosar®

Appearance:

Clear, light-yellow solution mixed into larger bags of fluids

This handout gives general information about this cancer medication.

You will learn:

who to contact for help
what the medication is
how it is given
what to expect while on medication

This handout was created by Ontario Health (Cancer Care Ontario) together with patients and their caregivers who have also gone through cancer treatment. It is meant to help support you through your cancer treatment and answer some of your questions.

This information does not replace the advice of your health care team. Always talk to your health care team about your treatment.

Who do I contact if I have questions or need help?

My cancer health care provider is: _____________________________________________

During the day I should contact: _______________________________________________

Evenings, weekends and holidays: _____________________________________________

This page gives general information about this cancer medication.

You will learn:

who to contact for help
what the medication is
how it is given
what to expect while on this medication

This information was created by Ontario Health (Cancer Care Ontario) together with patients and their caregivers who have also gone through cancer treatment. It is meant to help support you through your cancer treatment and answer some of your questions.

This information does not replace the advice of your health care team. Always talk to your health care team about your treatment.

What is this treatment for?

For treating cancer of the colon, rectum or other cancers

What should I do before I start this treatment?

Tell your health care team if you have or had significant medical condition(s), such as:

liver, heart or lung problems
diabetes
hereditary fructose intolerance or
any allergies

Remember To:

Tell your health care team about all of the other medications you are taking.
Keep taking other medications that have been prescribed for you, unless you have been told not to by your health care team.

You will have a blood test to check for hepatitis B before starting treatment. See the Hepatitis B and Cancer Medications pamphlet for more information.

How is this treatment given?

This drug is given by injection into a vein.

Other medications you may be given with this treatment

To Treat Diarrhea

The irinotecan in your treatment regimen can cause diarrhea. Diarrhea is when you have loose bowel movements (watery poo) or you need to have bowel movements (go poo) more often than usual. Diarrhea may start a few days after your treatment.

You will be given a medication called loperamide (Imodium®) to help treat your diarrhea. Take this medication only if you need it.

Keep your loperamide with you all the time. When diarrhea starts, take the loperamide right away.

If you start to have diarrhea:

Take 2 tablets (4 mg) of loperamide right away.
Take 1 tablet (2 mg) every 2 hours after that.
During the night you may take 2 tablets (4 mg) every 4 hours.
Keep taking loperamide until you have no diarrhea for 12 hours.

DO this while on treatment

DO check with your health care team before getting any vaccinations, surgery, dental work or other medical procedures.

DO NOT do this while on treatment

Stop Icon

DO NOT take any other medications, such as vitamins, over-the-counter (non-prescription) drugs or substances, or natural health products without checking with your health care team.

DO NOT start any complementary or alternative therapies, such as acupuncture or homeopathic products, without checking with your health care team.

DO NOT use tobacco products (such as smoking cigarettes or vaping) or drink alcohol while on treatment without talking to your health care team first. Smoking and drinking can make side effects worse and make your treatment not work as well.

DO NOT eat or drink grapefruit, starfruit, Seville oranges or their juices (or products that contain these) while on this treatment. These may increase the quantity of the medication in your blood and increase the side effects.

DO this while on treatment

Check Mark Icon

DO check with your health care team before getting any vaccinations, surgery, dental work or other medical procedures.

DO NOT do this while on treatment

Stop Icon

DO NOT take any other medications, such as vitamins, over-the-counter (non-prescription) drugs or substances, or natural health products without checking with your health care team.

DO NOT start any complementary or alternative therapies, such as acupuncture or homeopathic products, without checking with your health care team.

DO NOT use tobacco products (such as smoking cigarettes or vaping) or drink alcohol while on treatment without talking to your health care team first. Smoking and drinking can make side effects worse and make your treatment not work as well.

DO NOT eat or drink grapefruit, starfruit, Seville oranges or their juices (or products that contain these) while on this treatment. These may increase the quantity of the medication in your blood and increase the side effects.

Will this treatment interact with other medications or natural health products?

Yes, this medication can interact with other medications, vitamins, foods, traditional medicines and natural health products. Interactions can make this medication not work as well or cause severe side effects.

Tell your health care team about all of your:

prescription and over-the-counter (non-prescription) medications
other drugs and substances, such as cannabis/marijuana (medical or recreational)
natural health products such as vitamins, herbal teas, homeopathic medicines, and other supplements, or traditional medicines

Check with your health care team before starting or stopping any of them.

Talk to your health care team BEFORE taking or using these :

Anti-inflammatory medications such as ibuprofen (Advil^® or Motrin^®), naproxen (Aleve^®) or Aspirin^®.
Over-the-counter products such as dimenhydrinate (Gravol^®)
Natural health products such as St. John’s Wort
Traditional medicines
Supplements such as vitamin C
Grapefruit juice
Alcoholic drinks
Tobacco
All other drugs or substances, such as marijuana or cannabis (medical or recreational)

What to do if you feel unwell, have pain, a headache or a fever

Always check your temperature to see if you have a fever before taking any medications for fever or pain (such as acetaminophen (Tylenol^®) or ibuprofen (Advil^®)).
- Fever can be a sign of infection that may need treatment right away.
- If you take these medications before you check for fever, they may lower your temperature and you may not know you have an infection.

How to check for fever:

Keep a digital (electronic) thermometer at home and take your temperature if you feel hot or unwell (for example, chills, headache, mild pain).

You have a fever if your temperature taken in your mouth (oral temperature) is:
- 38.3°C (100.9°F) or higher at any time
OR
- 38.0°C (100.4°F) or higher for at least one hour.

If you do have a fever:

Try to contact your health care team. If you are not able to talk to them for advice, you MUST get emergency medical help right away.
Ask your health care team for the Fever pamphlet for more information.

If you do not have a fever but have mild symptoms such as headache or mild pain:

Ask your health care team about the right medication for you. Acetaminophen (Tylenol^®) is a safe choice for most people.

Talk to your health care team before you start taking ibuprofen (Advil^®, Motrin^®), naproxen (Aleve^®) or ASA (Aspirin^®), as they may increase your chance of bleeding or interact with your cancer treatment.

Talk to your health care team if you already take low dose aspirin for a medical condition (such as a heart problem). It may still be safe to take.

How will this treatment affect sex, pregnancy and breastfeeding?

Talk to your health care team about:

How this treatment may affect your sexual health
How this treatment may affect your ability to have a baby, if this applies to you

This treatment may harm an unborn baby. Tell your health care team if you or your partner are pregnant, become pregnant during treatment, or are breastfeeding.

If there is any chance you may become pregnant, you and your partner together must use 2 effective forms of birth control at the same time until 6 months after your last dose. Talk to your health care team about which birth control options are best for you.
If you are a patient that can get somebody pregnant, you and your partner together must use 2 effective forms of birth control at the same time until 3 months after your last dose. Talk to your health care team about which birth control options are best for you.

Do not breastfeed while on this treatment and for 7 days after your last dose.

What are the side effects of this treatment?

You may not have all of the side effects below. You may have side effects that are not listed.

Side effects and what to do	When to contact doctor?
More Common Side Effects (50 or more out of 100 people)

Diarrhea (early onset) and other early side effects of irinotecan

Starts during the infusion or within 24 hours
Some other symptoms include excessive sweating, belly cramps, runny nose, watery eyes, more saliva in the mouth, face or neck flushing or pinpointed pupils.
Let your healthcare team know right away if this happens. Medication(s) may be given to you to control these symptoms

Diarrhea (delayed onset)

Starts more than 24 hours to a few days after your irinotecan dose.
May be severe in some cases with dehydration

If you have diarrhea :

Take anti-diarrhea drug(s) as instructed by your healthcare team. Refer to "How it is given" section for instructions on using loperamide (Imodium®)
Avoid foods or drinks with artificial sweetener (e.g. chewing gum, “diet” drinks), coffee and alcohol, until your diarrhea has stopped.
Eat many small meals and snacks instead of 2 or 3 large meals.
Drink at least 6 to 8 cups of liquids each day. Talk to your health care team if you can’t drink 6-8 cups of liquids each day when you have diarrhea. You may need special liquids with salt and sugar, called Oral Rehydration Therapy.
If diarrhea lasts more than 24 hours while taking anti-diarrhea drugs or if you have fever, get emergency medical help right away.

See the Diarrhea pamphlet for more information.

Talk to your health care team if no improvement or if severe.

If diarrhea lasts more than 24 hours while taking anti-diarrhea drugs or if you have fever, get emergency medical help right away.

Nausea and vomiting

May occur in hours to days after your treatment. It is easier to prevent nausea than to treat it if it happens.

To help prevent nausea:

Take anti-nausea medication(s) as prescribed to you by your doctor.
Drink clear liquids and have small meals. Get fresh air and rest.
Do not eat spicy, fried foods or foods with a strong smell.
Limit caffeine (e.g. coffee, tea) and alcohol.

If you have nausea or vomiting:

Take anti-nausea medication(s) as prescribed to you by your doctor.
Contact your health care team if the prescribed anti-nausea medications are not helping to control your nausea and vomiting.

Also see Nausea & Vomiting pamphlet for more information.

Talk to your healthcare team if nausea lasts more than 48 hours or vomiting lasts more than 24 hours

Fatigue (tiredness)

Be active and aim to get 30 minutes of moderate exercise (you are able to talk comfortably while exercising) on most days. Check with your health care team before starting any new exercise.
Pace yourself, do not rush. Put off less important activities. Rest when you need to.
Eat well and stay hydrated by drinking at least 6 to 8 glasses of water or other liquids every day (unless your doctor told you to drink more or less).
Avoid driving or using machinery if you are feeling tired

See our Fatigue pamphlet for more information.

Talk to your health care team if no improvement or if severe

Hair thinning or loss

Use a gentle soft brush and avoid hair sprays, bleaches, dyes and perms.
In most cases, your hair will grow back after treatment, but the texture or colour may change.

Talk to your health care team if this bothers you

Pains or cramps in the belly

If you have constipation or diarrhea it may be causing the pain in your belly.
If the pain is severe, gets worse or doesn’t go away, talk to your health care team about other possible causes.

Talk to your health care team if no improvement or if severe

Low appetite

You may not feel like eating or you may lose weight.
Try to eat foods that you like and eat small meals throughout the day.
You may need to take meal supplements to help keep your weight up.
Talk to your health care team if you have a low appetite.
See our Loss of appetite pamphlet for more information.

Talk to your health care team if no improvement or if severe

Side effects and what to do	When to contact doctor?
Common Side Effects (25 to 49 out of 100 people)

Constipation (less common than diarrhea)

To help prevent constipation :

Drink more liquids and eat well. Drink at least 6 to 8 cups of liquids each day unless you have been told otherwise.
Be Active. Exercise can help to keep you regular.
Try to eat more fiber (e.g. fruits with skin, leafy greens and whole grains). If you take opioid pain medication, ask your health care team if eating more fibre is right for you.

To help treat constipation :

If you have not had a bowel movement in 2 to 3 days you may need to take a laxative. Ask your health care team what to do.

See the Constipation Pamphlet for more information.

Talk to your health care team if no improvement or if severe

Low platelets in the blood

Watch for bleeding (such as unusual nosebleeds or bleeding from the gums) or bruising easily (this is rare).
Very rarely, severe symptoms can happen. If you notice black coloured stools (poo), red or pink coloured urine (pee), red or brown coloured mucus when you cough, severe headache/confusion or bleeding that will not stop, you need to talk to your health care team or go to the nearest emergency room right away.

See the Low Platelet Count pamphlet for more information.

Fever, chills, infection

You have a fever if your temperature taken in your mouth (oral temperature) is:

38.3°C (100.9°F) or higher at any time OR
38.0°C (or 100.4°F) or higher for at least one hour.

While you are getting treatment:

Keep a digital thermometer at home and take your temperature if you feel hot or unwell (for example, chills).
Avoid taking medications that treat a fever before you take your temperature (for example, Tylenol®, acetaminophen, Advil® or ibuprofen) as they may hide a fever.
Do not eat or drink anything hot or cold right before taking your temperature.
Wash your hands often to prevent infection.
Check with your doctor before getting any vaccines, surgeries, medical procedures or visiting your dentist.

If you have a fever, talk to your health care team or go to the closest emergency room.
See our Neutropenia (Low white blood cell count) pamphlet for more information.

Get emergency medical help right away

Side effects and what to do	When to contact doctor?
Less Common Side Effects (10 to 24 out of 100 people)

Cough; feeling short of breath

You may have cough and feel short of breath without any signs of infection, such as a sore throat or a stuffed nose.

Rarely this may be severe with chest pain, trouble breathing or coughing up blood. If this happens get medical help right away.

Talk to your health care team if no improvement or if severe

Trouble falling asleep

This may be caused by one of your medications and may improve once your body gets used to the medication or when your treatment ends.
Talk to your doctor if this bothers you.

Talk to your health care team if no improvement or if severe

Headache; muscle pain or cramps

Take your pain medication as prescribed by your doctor.
You can take acetaminophen (Tylenol®) tablets as needed for mild aches and pains. Ask your doctor or pharmacist about the right dose for you.
Talk to your doctor or pharmacist first before taking ibuprofen (Advil®, Motrin®), naproxen (Aleve®) or aspirin. These medication may increase bleeding risk.
Rest often and try light exercise as it may help.

Talk to your health care team if no improvement or if severe

Dizziness

You may feel light headed.
Lay down if this happens.
Get up and move slowly once you feel better.
Do not drive a motor vehicle or use machinery if you feel dizzy.

Talk to your health care team if no improvement or if severe

Abnormal liver lab tests

You may have yellowish skin or eyes, unusually dark pee or pain on the right side of your belly. Talk to your health care team if this happens.
Your doctor may monitor your liver regularly with a blood test.

Talk to your health care team if no improvement or if severe

Rash; dry, itchy skin

Rash may be severe in some rare cases and cause your skin to blister or peel. If this happens, get emergency medical help right away.

To prevent and treat dry skin,

Use skin moisturizer.
Protect your skin from the sun and the cold.
Use sunscreen with UVA and UVB protection and a SPF of at least 30.

Talk to your health care team if no improvement or if severe

Mouth sores

You may have round, painful, white or gray sores inside your mouth. They can occur on the tongue, lips, gums, or inside your cheeks. In more severe cases they may make it hard swallow, eat or to brush your teeth. They usually last 1 to 2 weeks.

To help prevent mouth sores:

Take care of your mouth by gently brushing and flossing regularly.
Rinse your mouth often. Do not use mouthwashes with alcohol.
Instead, try a homemade mouthwash:
Mix 1 teaspoonful of baking soda and 1 teaspoonful of salt in 4 cups (1L) of water.

If you have mouth sores:

Check with your health care team as soon as you notice mouth or lip sores or if it hurts to swallow.
Avoid hot, spicy, acidic, hard or crunchy foods. Your doctor may prescribe a mouthwash to relieve mouth sores and prevent infection.

See the Mouth Care pamphlet for more information.

Talk to your health care team as soon as possible

Heartburn; stomach upset

To help prevent heartburn:

Avoid fatty or spicy foods.
Remain upright after eating.
Drink clear liquids and eat small meals.

Talk to your health care team if no improvement or if severe

Mild swelling in arms and legs; puffiness

To help prevent swelling :

Eat a low-salt diet.
Avoid tight fitting clothing.

If you have swelling in your legs, keep your feet up when sitting.

Talk to your health care team if no improvement or if severe

Other rare, but serious side effects are possible with this treatment.

If you have any of the following, talk to your cancer health care team or get emergency medical help right away:

Swelling and hardening of a vein in your arms or leg
Feel confused, trouble seeing, speaking, or using your arms or legs
Severe or sudden belly pain, bloating or feeling of fullness and severe constipation
Pain in the centre of your belly that may extend to your back
Flushing, itchiness, rash, swollen lips, face or tongue, wheezing, chest and throat tightness
Fever, severe joint pain; lower back pain, swelling, pee less than usual and have unusual weight gain; muscle twitching, severe weakness or cramping and feel confused

For more information on how to manage your symptoms ask your health care provider, or visit: https://www.cancercareontario.ca/symptoms.

Notes

August 2025 Updated/revised information sheet

The information set out in the medication information sheets, regimen information sheets, and symptom management information (for patients) contained in the Drug Formulary (the "Formulary") is intended to be used by health professionals and patients for informational purposes only. The information is not intended to cover all possible uses, directions, precautions, drug interactions or side effects of a certain drug, nor should it be used to indicate that use of a particular drug is safe, appropriate or effective for a given condition.

A patient should always consult a healthcare provider if he/she has any questions regarding the information set out in the Formulary. The information in the Formulary is not intended to act as or replace medical advice and should not be relied upon in any such regard. All uses of the Formulary are subject to clinical judgment and actual prescribing patterns may not follow the information provided in the Formulary.

Info Sheet (English):

irinotecan patient.pdf Info Sheet (French):

irinotcan pour le patient.pdf Monograph:

irinotecan.pdf Phonetic Spelling:

eye-reen-oh-TEE-can

Eligibility Form:

Cetuximab with Irinotecan - Metastatic Colorectal, Small Bowel, or Appendiceal Cancer Cancer Type: Breast Central Nervous System Gastrointestinal Colorectal Esophagus Gastric / Stomach Hepatobiliary / Liver / Bile Duct Neuroendocrine (GI) Pancreas Rectal Small bowel and appendix Genitourinary Bladder / Urothelial Prostate Gynecologic Cervix Endometrial Ovary Head and Neck Lung Small Cell Sarcoma Ewing's Type of Content: Drug Monograph Status: Null Info Sheet Status: Null Global Date: Thursday, August 14, 2025 Universal Date: 2025-08-21 00:00:00 AddThis: Title URL: irinotecan Drug Display Status: Active Revision Summary:
Drug Monograph: Updated Pregnancy/Lactation section
Patient Info Sheet EN: Updated/revised information sheet
Patient Info Sheet FR: Updated/revised information sheet (Fiche d’information mise à jour/révisée)