Oncura

FOLFIRI: what to expect, day by day

Colorectal14-day cycle5 effects documented

An every-2-week infusion with a take-home 5-FU pump. The key thing to watch is diarrhea — an early crampy type during infusion, and a later type a few days after that needs prompt anti-diarrheal treatment.

5-FU + leucovorin + irinotecan every 2 weeks. Irinotecan causes TWO diarrheas: an early cholinergic one during/right after the infusion (treated with atropine), and a late one from about day 5 that can be severe.

Get help straight away — this is true on any regimen, on any day.

A temperature of 100.4°F (38°C) or higher during treatment can mean a serious infection while your blood counts are low. Call your team or go to the ER — do not wait it out.

Also urgent: trouble breathing or chest pain · swelling of the face, lips or throat · new confusion or fainting · shaking chills · not being able to keep fluids down.

This is standing guidance shown to everyone. Nothing on this page is based on anything about you, and nobody is monitoring you.

Timed to the cycle

Day 1 is the day of your infusion. These are the effects a retrievable document ties to a day range for this regimen — not a prediction about you.

Diarrhea (early / cholinergic)

Typically around days 5–11

During or shortly after the irinotecan infusion, some people get crampy diarrhea along with sweating, watery eyes, or a runny nose. Your team can give atropine to prevent or treat it — tell your nurse right away if it starts.

Call your team: Tell your infusion nurse immediately if cramping/diarrhea starts during treatment.

reported by about ~45% of people · Timing from the manufacturer’s prescribing information · from Irinotecan

Diarrhea (late-onset)

Typically around days 5–11

A separate, often more serious diarrhea that typically starts around day 5. Start loperamide at the FIRST loose stool per your team's instructions and drink fluids — untreated it can cause dangerous dehydration. People with a UGT1A1 gene variant are at higher risk.

Call your team urgently: More than 6 stools above normal, diarrhea with fever, or any with lightheadedness — call urgently.

reported by about ~65% of people; severe in 20-30% · Timing from the manufacturer’s prescribing information · from Irinotecan

Neutropenia

Typically around days 8–27

A temporary drop in infection-fighting white cells; higher risk with the UGT1A1 gene variant.

Call your team urgently: A temperature of 100.4°F (38.0°C) or higher — an emergency.

reported by about ~54% of people; severe in 24-30% · Timing from a drug-monograph reference · from Irinotecan, Fluorouracil

Not tied to a cycle day

These build with the number of doses, or are measured from when treatment started, so a cycle day would be the wrong shape for them. Each keeps the timing its own source states.

Nausea

Sickness in the first 24 hours is the "acute" phase and usually peaks 2-3 hours in; anything from 24 to 120 hours is the "delayed" phase.

Usually well controlled with anti-nausea medicine given before treatment.

Call your team: Can't keep fluids down for more than 12 hours.

reported by about ~70% of people; severe in 2-10% · Timing from a clinical guideline · from Irinotecan, Fluorouracil

Hair loss

over the first weeks

Thinning or loss of hair that grows back after treatment ends.

reported by about ~60% of people · from Irinotecan

Where this comes from

  1. S1. Irinotecan (Camptosar) FDA prescribing information — FDA label
  2. S2. Fluorouracil (5-FU) FDA prescribing information — FDA label
  3. S3. Douillard JY, irinotecan+5FU/LV first-line CRC (2000) — PMID 10744089

Timing windows on this page rest on:

A window appears here only where a retrievable document ties it to a drug in this regimen. Where nothing could be found, the window was removed rather than estimated — so a missing time is an honest gap, not an oversight.

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