OpenClaim

Trifluridine Side Effects

The most commonly reported side effects of trifluridine include death, disease progression, and fatigue, based on 10,870 FDA adverse event reports from 2004 to 2025. 3.7% of reports found the drug to be ineffective.

Trifluridine side effects

Percentages show how often each reaction appears relative to total reports for trifluridine.

1
Death28.5%3,102
2
Disease Progression16.6%1,801
3
Fatigue12.7%1,378
4
Nausea10.8%1,169
5
Diarrhoea9.4%1,027
6
Decreased Appetite6.3%683
7
Vomiting5.8%629
8
White Blood Cell Count Decreased4.4%483
9
Asthenia4.4%479
10
Drug Ineffective3.7%406
11
Anaemia3.4%373
12
Neutropenia3.3%354
13
Constipation3.0%330
14
Weight Decreased3.0%329
15
Off Label Use3.0%328

These are voluntary reports and do not establish that trifluridine caused these reactions.

Report severity

78.1%Serious8,489 reports
27.0%Hospitalizations2,936 reports
38.9%Fatal4,228 reports

Seriousness is determined by the reporter, not by OpenClaim.

Trifluridine drug interactions

Other drugs that appear in adverse event reports alongside trifluridine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Tipiracil92.0%10,003
2
Bevacizumab7.3%792
3
Regorafenib3.3%354
4
Irinotecan-hydrochloride2.7%289
5
Oxaliplatin2.6%279
6
Fluorouracil2.2%234
7
Capecitabine1.4%154
8
Panitumumab1.3%142
9
Levoleucovorin1.2%128
10
Cetuximab0.7%79
11
Leucovorin-calcium0.5%52
12
Fruquintinib0.4%44
13
Aflibercept0.4%39
14
Nivolumab0.3%36
15
Cenegermin-bkbj0.3%32

Taken alongside

1
Ondansetron12.2%1,322
2
Acetaminophen8.5%925
3
Oxycodone7.7%833
4
Amlodipine7.1%772
5
Prochlorperazine6.9%749
6
Gabapentin6.8%740
7
Omeprazole5.7%622
8
Lisinopril5.5%593
9
Metoprolol5.4%588
10
Aspirin5.2%566
11
Ergocalciferol5.1%549
12
Levothyroxine-sodium4.8%524
13
Pantoprazole-sodium4.8%521
14
Atorvastatin-calcium4.6%496
15
Furosemide4.4%481

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports trifluridine side effects

41.1% of trifluridine adverse event reports involve female patients and 56.4% involve male patients. The largest age group is adult at 50%. These figures reflect who reports side effects, not underlying risk.

Sex

Female41.1%
Male56.4%
Unknown2.5%

Age group

< 2<0.1%
2–11<0.1%
12–17<0.1%
18–6450.4%
65+49.5%

What is trifluridine used for

Conditions and purposes for which patients were taking trifluridine when the adverse event was reported.

Abdominal NeoplasmAdenocarcinomaAdenocarcinoma Of AppendixAdenocarcinoma Of ColonAgranulocytosisAnaemiaAnaemia Of Chronic DiseaseAnal CancerAnorectal DisorderAppendix CancerAdenocarcinoid Tumour Of The AppendixAdenocarcinomaAdenocarcinoma GastricAdenocarcinoma MetastaticAdenocarcinoma Of Appendix

Showing 15 of 267 indications

Trifluridine brand names and reporting trend

Trifluridine is sold under the brand name Lonsurf.

Brand names

Lonsurf519

Quarterly reports (20042025)

20042010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking trifluridine with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.