Milbemycin Oxime + Spinosad (Trifexis): adverse event reports that FDA received
Combination of 2 active ingredients
The name in brackets is a brand name with these active ingredients.
The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand.
Read this first. FDA says this about the data:
An API dataset query result cannot be used to estimate the risk associated with the product or compare one drug or device product with another. When looking at the results, be aware that there is no certainty that the reported drug or device caused the adverse event. This dataset should not be the sole source of information for clinical decision-making or other assumptions about the safety or effectiveness of a product. The adverse event may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources.
FDA Center for Veterinary Medicine publishes these words. Source: Adverse Event Reports for Animal Drugs and Devices, read on . The data have the reports that FDA received through .
This page is not veterinary advice. For an animal that is ill, speak to a veterinarian.
Contacting a veterinarianHow to report to FDAFrom June 2009 to June 2026, FDA received 140,813 adverse event reports that name a drug with milbemycin oxime and spinosad as its active ingredients. Of the 140,813 reports, 129,740 (92.1%) are about dogs.
In January to March 2026, FDA received 166 reports that name this drug. The signs that appear in the largest number of the 140,813 reports are "Emesis", "Vomiting" and "Lethargy". A report is not proof that a drug caused a sign.
Reports that name this drug fell by 20.8% in the 12 months to June 2026, compared with the 12 months before. Reports for all animal drugs fell by 4.6% in the same periods. The newest months can get more reports in a later update. Reports about dogs are 92.1% of the reports that name this drug, and 72.6% of all reports.
Since the last update of the FDA data
The site recorded an update of the FDA data on . FDA changed these counts for January to March 2026:
- All species: from 153 to 166.
- Dog: from 142 to 155.
January to March 2026 is the latest closed quarter in the data. In that quarter FDA received 166 reports that name milbemycin oxime + spinosad: 155 dog, 0 cat, 0 horse, 11 other or not given.
Signs that the reports list
A sign is a coded term from the report. The words in brackets are a plain gloss of the term. The percentage is the share of the 140,813 reports that list the sign. One report can list more than one sign.
The sign that is in the largest number of the reports comes first.
- Emesis[vomiting]29.5%41,538 reports
- Vomiting22.7%32,022 reports
- Lethargy[unusually tired or inactive]13.3%18,768 reports
- Unpalatable[legacy FDA term: the animal would not take it]8.6%12,067 reports
- Lack of efficacy - NOS[the product did not have the expected effect]8.1%11,438 reports
- Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]5.1%7,201 reports
- Diarrhoea[diarrhea]4.7%6,629 reports
- Ineffective, heartworm larvae[legacy FDA term: the product did not have the expected effect (heartworm larvae)]4%5,632 reports
- Lack of efficacy (endoparasite) - heartworm[the product did not have the expected effect: heartworm]3.6%5,117 reports
- Seizure NOS[seizure, type not specified]3%4,209 reports
- Behavioural disorder NOS[behaviour change, type not specified]2.7%3,793 reports
- Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]2.1%2,983 reports
- Shaking1.9%2,701 reports
- Weight gain1.9%2,621 reports
Show the next 16 signs
- Anorexia[not eating]1.9%2,613 reports
- Product problem[a product quality report, not a sign in an animal]1.8%2,602 reports
- Ataxia[unsteady, uncoordinated movement]1.8%2,552 reports
- Emesis (multiple)[vomiting more than once]1.8%2,514 reports
- Other abnormal test result NOS[abnormal laboratory result, type not specified]1.8%2,503 reports
- Not eating1.8%2,490 reports
- Itching1.6%2,260 reports
- Decreased appetite1.5%2,093 reports
- Overdose[more than the labelled amount was given]1.5%2,061 reports
- Weight loss1.4%1,992 reports
- Death1.4%1,952 reports
- Pruritus[itching]1.4%1,947 reports
- Accidental exposure[exposure that was not intended]1.2%1,757 reports
- Trembling1.2%1,655 reports
- Lack of efficacy (flea)[the product did not have the expected effect: fleas]1.1%1,521 reports
- Odor, Abnormal[a product quality report, not a sign in an animal]1.1%1,496 reports
The list shows 30 of 1,988 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)
Reports by species
- Dog92.1%129,740
- Cat0.2%300
- Human exposure0.2%249
- Other Canidsunder 0.1%8
- Otherunder 0.1%6
- Wolfunder 0.1%2
The share is of all 140,813 reports that name milbemycin oxime + spinosad. The other reports give a different species or no species.
Reports for each month, Jul 2021 to Jun 2026
No chart: no month has 5 or more reports.
No chart: no month has 5 or more reports.
The month is the month in which FDA received the report. Each chart has its own scale. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.
Reports by year
- Dog
- Cat
- Horse
- Other or not given
| Year | Dog | Cat | Horse | Other or not given | All species |
|---|---|---|---|---|---|
| 2026 | 277 | 0 | 0 | 15 | 292 |
| 2025 | 703 | 1 | 0 | 70 | 774 |
| 2024 | 894 | 2 | 0 | 52 | 948 |
| 2023 | 1,199 | 5 | 0 | 75 | 1,279 |
| 2022 | 1,700 | 6 | 0 | 116 | 1,822 |
| 2021 | 2,744 | 5 | 0 | 205 | 2,954 |
| 2020 | 4,528 | 14 | 0 | 350 | 4,892 |
| 2019 | 5,974 | 9 | 0 | 274 | 6,257 |
| 2018 | 7,245 | 19 | 0 | 634 | 7,898 |
| 2017 | 9,140 | 18 | 0 | 803 | 9,961 |
| 2016 | 11,187 | 24 | 0 | 868 | 12,079 |
| 2015 | 15,037 | 36 | 0 | 1,456 | 16,529 |
| 2014 | 17,887 | 30 | 0 | 1,877 | 19,794 |
| 2013 | 23,142 | 59 | 0 | 2,118 | 25,319 |
| 2012 | 20,921 | 54 | 0 | 1,527 | 22,502 |
| 2011 | 7,157 | 18 | 0 | 333 | 7,508 |
| 2010 | 4 | 0 | 0 | 0 | 4 |
| 2009 | 1 | 0 | 0 | 0 | 1 |
2026 has the reports that FDA received through Jun 2026. Download the years (CSV)
What the reports record
Outcome at the time of the report
- Recovered/Normal53.7%75,563
- Recovered with Sequela[recovered, with a lasting effect]4.7%6,664
- Ongoing5.4%7,662
- Died1.6%2,250
- Euthanized0.9%1,236
- Outcome Unknown23.8%33,555
An outcome in a report is not proof that the drug caused it. The person who sends the report gives the outcome. Each share is of the 140,813 reports that name milbemycin oxime + spinosad.
A report about more than one animal can have more than one outcome.
Kind of report
- Safety issue70.9%99,889
- Lack of expected effectiveness11.8%16,631
- Both safety and lack of expected effectiveness4.3%5,991
- Manufacturing or product defect13%18,288
- Otherunder 0.1%14
126,750 reports say if the event was serious. 12% of them have the serious flag. The person who sends the report sets the flag.
Show age, weight, breed and route
Age of the animal
- Under 1 year15.4%21,621
- 1 to 3 years33.3%46,857
- 4 to 7 years22.6%31,810
- 8 to 11 years11.5%16,151
- 12 years and over4.5%6,296
- Age not given12.8%18,078
Weight of the animal
- Under 5 kg (11 lb)14.4%20,219
- 5 to 9.9 kg (11 to 22 lb)21.2%29,897
- 10 to 24.9 kg (22 to 55 lb)23.9%33,701
- 25 to 44.9 kg (55 to 99 lb)25.6%36,050
- 45 kg and over (99 lb and over)2.4%3,435
- Weight not given12.4%17,511
Breed, where the report gives one breed
- Labrador Retriever6.8%9,610
- Yorkshire Terrier3%4,222
- Chihuahua2.9%4,015
- Shih Tzu2.7%3,795
- German Shepherd Dog2.6%3,725
- Boxer2.6%3,678
- Golden Retriever2.3%3,234
- Pit Bull1.9%2,688
A breed with many animals has many reports.
Route in the report
- Oral91.8%129,272
- Cutaneousunder 0.1%49
- Topicalunder 0.1%35
- Otherunder 0.1%25
- Respiratory (Inhalation)under 0.1%9
- Intraocularunder 0.1%5
Each bar is on a scale of 0 to 100%.
Approved animal drugs with these active ingredients (FDA Green Book)
This section is reference data. It has no report count.
The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand.
Brand names
- Trifexis
What the Green Book records give
- Applications with an approval in force
- 1
- Approved species
- Dogs
- Dose forms
- Chewable Tablets
- Routes
- Oral
- Sale
- RX (prescription)
- Earliest approval date in the records
The species, dose forms and routes are the words of the Green Book records for all the applications together. One product can have fewer. The label of a product gives its approved use.
| Brand name | Active ingredients | Sponsor | Approved species | Application |
|---|---|---|---|---|
| Trifexis | Milbemycin Oxime, Spinosad | Elanco US Inc. | Dogs | NADA 141-321 |
Other pages with one of these ingredients
A report names a drug by its set of active ingredients. Each set has its own page. The list is in order of name.
Next in the A to Z list
FDA pages for this drug
- How to Report Animal Drug and Device Side Effects and Product ProblemsThe FDA page that tells an owner or a veterinarian how to send a report.
- Green Book record of NADA 141-321The FDA record of the application for Trifexis.Client Information Sheet of Trifexis (PDF): a label document that FDA posts with the record.
- Animal Drugs @ FDAThe search page of the Green Book, the FDA list of approved animal drugs.
The site checked these addresses on . The links open in a new tab.
Cite this page
Pet Drug Reports. Milbemycin Oxime + Spinosad: adverse event reports that FDA received. https://petdrugreports.com/drug/milbemycin-oxime-spinosad/ Source: FDA Center for Veterinary Medicine, openFDA Animal and Veterinary adverse event reports, export of . Reports received through .
Where the data come from
The counts come from the openFDA Animal and Veterinary adverse event files, export of 30 Oct 2026. The files have the reports that the FDA Center for Veterinary Medicine received through 26 Jun 2026. The files mask brand and manufacturer names. The site counts a drug by the active ingredients that each record gives, and gives no count to a brand, an application or a company. Ingredient names and the lists of approved products follow the FDA Green Book of 2 Nov 2026. The site does not use the application number that a record has.
The site does not publish report text, lot numbers or details of a reporter. FDA's record is the authority. See how the site counts reports, the data sources and the corrections page.
Questions about these reports
- Which brand are these reports about?
The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand. The Green Book section of this page lists the brand names with these active ingredients.
- Do the reports show that the drug caused the signs?
No. FDA states this about the data.
When looking at the results, be aware that there is no certainty that the reported drug or device caused the adverse event.
The adverse event may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources.
FDA Center for Veterinary Medicine. Source: Adverse Event Reports for Animal Drugs and Devices
- How many reports did FDA receive in the latest 12 months?
FDA received 659 reports in the 12 months to June 2026. It received 832 reports in the 12 months before. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.
- What kinds of report are in the count?
Of the 140,813 reports received from June 2009 to June 2026, 70.9% are about a safety issue only. 16.1% are about a lack of expected effectiveness, alone or with a safety issue. 13% are about a defect of the product or its package.