Pet Drug Reports

Ingredients

Active ingredient · pooled across combinations

Lufenuron: adverse event reports, pooled

11 ingredient sets in reports · 8 FDA-approved applications in the Green Book

39,711reports naming the ingredient, 1995–20262.9% of all reports · about 1,271 a year
1,171reports, 12 months to March 20261,173 in the 12 months before
35.5%classed serious, as reportedall reports: 38.6%
92.2%of reports concern dogscat 2.9%

Lufenuron appears, alone or combined with other ingredients, in 39,711 reports in FDA's animal adverse event database (January 1995 to March 2026). The figures here pool all 11 ingredient sets that include it.

The Green Book lists 8 FDA-approved applications containing it. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand.

1,171 reports arrived in the 12 months to March 2026, close to the 1,173 of the 12 months before. FDA posts reports quarterly with a delay of three to six months, so the newest months are incomplete and usually grow in later releases. That is about 1,271 reports a year over its reporting history and 2.9% of all reports.

Pooled across every set, the terms listed most often are ineffective, heartworm larvae (14.4%), vomiting (14.2%) and lack of efficacy (endoparasite) - hookworm (10.7%). Many drugs combine several ingredients, and many reports list several drugs, so a term on this page may relate to any of them or to none.

Of reports that state seriousness, 35.5% were classed as serious (38.6% across the whole database); 2.2% record a death or euthanasia (6.4% overall). Ingredients used in older or sicker animals, or in anaesthesia and cancer care, carry higher shares for that reason alone.

Ingredient sets that include lufenuron

Active ingredients recorded for the drugReportsShare of this page's reportsLatest 12 months
Lufenuron + Milbemycin Oxime27,52269.3%424
Lufenuron + Milbemycin Oxime + Praziquantel6,70416.9%761
Lufenuron + Praziquantel3,5268.9%1
Lufenuron2,3706%3
Lufenuron + Nitenpyram20%0
Afoxolaner + Lufenuron + Milbemycin Oxime20%2
Ivermectin + Lufenuron + Praziquantel + Pyrantel Pamoate10%0
Ivermectin + Lufenuron10%0
Lufenuron + Milbemycin Oxime + Spinosad10%0
Ivermectin + Lufenuron + Praziquantel10%0
Fenbendazole + Ivermectin + Lufenuron + Praziquantel + Pyrantel Pamoate10%0

Ordered by report count. FDA states that these data "cannot be used to estimate the risk associated with the product or compare one drug or device product with another"; counts follow sales volume and years on the market. A report can list more than one set, so shares can add to more than 100%.

Signs listed in reports, pooled

share of lufenuron reports listing the termall reports in the database

  1. Ineffective, heartworm larvae[legacy FDA term: the product did not have the expected effect (heartworm larvae)]14.4%5,705
  2. Vomiting14.2%5,631
  3. Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]10.7%4,233
  4. Lack of efficacy (endoparasite) - heartworm[the product did not have the expected effect: heartworm]8.9%3,523
  5. Diarrhoea[diarrhea]7.9%3,146
  6. Lethargy[unusually tired or inactive]5.3%2,090
  7. Ineffective, ascarids NOS[legacy FDA term: the product did not have the expected effect (ascarids nos)]5%2,000
  8. Ineffective, hooks[legacy FDA term: the product did not have the expected effect (hooks)]4.7%1,869
  9. Lack of efficacy - NOS[the product did not have the expected effect]3.5%1,371
  10. Depression[dull, quiet or withdrawn]3.4%1,343
  11. Lack of efficacy (endoparasite) - whipworm[the product did not have the expected effect: whipworms]3.3%1,328
  12. Anorexia[not eating]3.3%1,292
  13. Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]3.2%1,284
  14. Pruritus[itching]2.7%1,053
  15. Emesis[vomiting]2.4%938
  16. Lack of efficacy (endoparasite) - roundworm NOS[the product did not have the expected effect: roundworms]2.1%853
  17. Seizure NOS[seizure, type not specified]2%795
  18. Emesis (multiple)[vomiting more than once]1.8%701
  19. Ataxia[unsteady, uncoordinated movement]1.7%670
  20. Underfilling, Package[a product quality report, not a sign in an animal]1.7%656
  21. Lack of efficacy (endoparasite) - tapeworm[the product did not have the expected effect: tapeworms]1.4%569
  22. Bloody diarrhoea[diarrhea with blood]1.4%546
  23. Product problem[a product quality report, not a sign in an animal]1.3%529
  24. Overdose[more than the labelled amount was given]1.3%507
  25. Drug dose omission[a scheduled administration was missed]1.2%489
  26. Underdose[less than the labelled amount was given]1.2%469
  27. Lack of efficacy (roundworm)[the product did not have the expected effect: roundworms]1.1%456
  28. Death1.1%452
  29. Convulsion[seizure]1.1%451
  30. Other abnormal test result NOS[abnormal laboratory result, type not specified]1.1%444

Pooled across every ingredient set and every report that names the ingredient. One report can list several terms and several drugs; a term here may relate to any of them or to none.

Monthly reports by species, five years

Dog6,256 · peak 170
Apr 2021: 170May 2021: 125Jun 2021: 118Jul 2021: 158Aug 2021: 134Sep 2021: 117Oct 2021: 114Nov 2021: 103Dec 2021: 86Jan 2022: 106Feb 2022: 94Mar 2022: 132Apr 2022: 125May 2022: 156Jun 2022: 124Jul 2022: 101Aug 2022: 128Sep 2022: 112Oct 2022: 109Nov 2022: 85Dec 2022: 61Jan 2023: 99Feb 2023: 108Mar 2023: 91Apr 2023: 107May 2023: 107Jun 2023: 105Jul 2023: 103Aug 2023: 136Sep 2023: 78Oct 2023: 99Nov 2023: 82Dec 2023: 65Jan 2024: 110Feb 2024: 103Mar 2024: 109Apr 2024: 111May 2024: 117Jun 2024: 102Jul 2024: 107Aug 2024: 89Sep 2024: 92Oct 2024: 124Nov 2024: 76Dec 2024: 85Jan 2025: 88Feb 2025: 64Mar 2025: 82Apr 2025: 95May 2025: 113Jun 2025: 137Jul 2025: 120Aug 2025: 104Sep 2025: 101Oct 2025: 115Nov 2025: 82Dec 2025: 83Jan 2026: 75Feb 2026: 67Mar 2026: 672022202320242025
Cat3 · peak 2
Jun 2021: 2Aug 2022: 12022202320242025
Horse0 · peak 1
2022202320242025
Other190 · peak 9
Apr 2021: 5May 2021: 5Jun 2021: 2Jul 2021: 6Aug 2021: 4Sep 2021: 2Oct 2021: 5Nov 2021: 6Dec 2021: 2Feb 2022: 5Mar 2022: 6Apr 2022: 3May 2022: 4Jun 2022: 4Aug 2022: 7Sep 2022: 2Oct 2022: 6Nov 2022: 7Dec 2022: 2Jan 2023: 3Feb 2023: 1Mar 2023: 8Apr 2023: 3May 2023: 4Jun 2023: 4Jul 2023: 3Aug 2023: 2Sep 2023: 8Oct 2023: 4Nov 2023: 7Dec 2023: 5Jan 2024: 1Feb 2024: 1Mar 2024: 5Apr 2024: 1May 2024: 9Jun 2024: 3Jul 2024: 7Aug 2024: 1Sep 2024: 1Oct 2024: 2Nov 2024: 2Dec 2024: 4Jan 2025: 4Mar 2025: 2Apr 2025: 1Jun 2025: 3Jul 2025: 1Aug 2025: 4Sep 2025: 2Nov 2025: 12022202320242025

By month of receipt; each panel has its own scale. The newest months are incomplete because FDA posts reports with a delay of three to six months.

01,6383,2751995: 22719951996: 4321997: 1231998: 27019981999: 4992000: 4092001: 25520012002: 1942003: 2242004: 53120042005: 5522006: 7492007: 97120072008: 1,1252009: 1,2562010: 1,19520102011: 1,2432012: 1,0692013: 1,27920132014: 2,9412015: 3,1342016: 3,27520162017: 3,1972018: 2,8442019: 2,60120192020: 2,2182021: 1,6132022: 1,38020222023: 1,2322024: 1,2622025: 1,20220252026: 209

Outcomes, report types and ages

Outcome recorded in the report

Recovered/Normal21.1%8,382
Recovered with Sequela0.4%169
Ongoing18.6%7,370
Died1.6%644
Euthanized0.6%243
Outcome Unknown29.6%11,735

What kind of report it was

Safety issue49.7%19,746
Lack of expected effectiveness36.8%14,627
Both safety and lack of expected effectiveness8.3%3,302
Manufacturing or product defect5.1%2,033
Other0%3

Species

Dog92.2%36,594
Cat2.9%1,148
Human exposure0.3%108
Other0%3
Goat0%2

Age of the animal

Under 1 year10.5%4,156
1 to 3 years33.5%13,311
4 to 7 years25.5%10,138
8 to 11 years16%6,336
12 years and over6.2%2,444
Age not given8.4%3,326

Coloured bar: reports naming lufenuron. Grey bar: all 1,357,245 reports. Outcomes are as stated by the reporter; FDA has not necessarily determined whether any product played a part.

In context

MeasureLufenuronAll reports
Reports39,7111,357,245
Latest 12 months against the 12 before0%-5%
Classed serious, of reports stating it35.5%38.6%
Death or euthanasia recorded, per 1,000 reports22.363.8
Filed as lack of expected effectiveness (wholly or partly)45.1%23%

Shares of reports, not of animals treated: how many animals receive the ingredient is not public. Ingredients used in anaesthesia, cancer care or in old animals carry more serious outcomes in their reports for that reason alone.

FDA-approved products containing lufenuron (Green Book)

Reference information, not report statistics. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand. The list below is the FDA Green Book as of 30 Sep 2026; nothing on this page says which of these products, if any, a report concerned.

Trade nameActive ingredientsSponsorApproved forApplication
Program SuspensionLufenuronElanco US Inc.CatsNADA 141-026
Program Flavor TabsLufenuronElanco US Inc.Dogs, CatsNADA 141-035
Program Cat Flavor TabsLufenuronElanco US Inc.CatsNADA 141-062
Sentinel Flavor TabsLufenuron, Milbemycin OximeIntervet, Inc.DogsNADA 141-084
Program 6 Month Injectable for CatsLufenuronElanco US Inc.CatsNADA 141-105
Sentinel Flavor Tabs and Capstar Flea Management SystemLufenuron, Milbemycin Oxime, NitenpyramIntervet, Inc.DogsNADA 141-204
Program Flavor Tabs and Capstar Flea Management SystemLufenuron, NitenpyramElanco US Inc.Dogs, CatsNADA 141-205
Sentinel SpectrumLufenuron, Milbemycin Oxime, PraziquantelIntervet, Inc.DogsNADA 141-333

Species are the major species the Green Book search lists for the application ("—" where it lists another species or none). Approval dates are not part of the Green Book listing files and are not shown. Pioneer applications (NADA) come first, then generics (ANADA).

Questions about lufenuron reports

How many FDA adverse event reports mention lufenuron?

39,711 reports through March 2026, 1,171 of them in the latest 12 months, counting lufenuron alone and in combinations.

Which brands do these reports concern?

That cannot be known from the public data. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand. The Green Book reference list on this page names approved products containing lufenuron without any counts.

In which combinations is lufenuron reported?

Lufenuron + Milbemycin Oxime (69.3% of these reports), Lufenuron + Milbemycin Oxime + Praziquantel (16.9% of these reports), Lufenuron + Praziquantel (8.9% of these reports), Lufenuron (6% of these reports) and Lufenuron + Nitenpyram (0% of these reports).

What reactions are reported for lufenuron?

ineffective, heartworm larvae (14.4%), vomiting (14.2%), lack of efficacy (endoparasite) - hookworm (10.7%), lack of efficacy (endoparasite) - heartworm (8.9%) and diarrhoea (7.9%). Shares are of reports naming the ingredient; one report can list several terms.

Which animals are these reports about?

dog (92.2%), cat (2.9%) and human exposure (0.3%).

Does a high count mean lufenuron is a problem ingredient?

A count cannot show that. FDA states that "there is no certainty that the reported drug or device caused the adverse event" and that the event "may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources." Widely used ingredients collect more reports because more animals receive them.

How do I report a problem?

Call the drug company using the number on the label, or send Form FDA 1932a to FDA. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Animal & Veterinary adverse event bulk files released 28 Sep 2026, which hold reports FDA's Center for Veterinary Medicine received through 31 Mar 2026. openFDA masks brand and manufacturer names in these files, so drugs are counted by the active ingredients each record discloses and no figure is attributed to a brand, application or company. Ingredient names, and the separate reference lists of approved products, follow the FDA Green Book as of 30 Sep 2026. Ingredient names follow the Green Book; salts and forms are kept as FDA lists them. Drug entries are matched by the active ingredients their unmasked ingredient field discloses. No report text, lot numbers or reporter details are published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.