Pet Drug Reports

Mebendazole + Trichlorfon (Telmin B)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 FDA

From January 1987 to October 1995, FDA received 75 adverse event reports that name a drug with mebendazole and trichlorfon as its active ingredients. Of the 75 reports, 71 (94.7%) are about horses. 4 reports are about dogs (5.3%).

In January to March 2026, FDA received no reports that name this drug. The signs that appear in the largest number of the 75 reports are "Abdominal pain", "Diarrhoea" and "Anorexia". A report is not proof that a drug caused a sign.

Fewer than 20 reports named this drug in the 12 months before June 2026, so this page gives no change. Reports about horses are 94.7% of the reports that name this drug, and 1.4% of all reports.

Search engines list a drug page with 500 reports or more in all years. The page also needs 30 reports or more in the 12 months to June 2026. This page is under one of these numbers. The site keeps the page and keeps it out of search engines.

Since the last update of the FDA data

The latest update of the FDA data, recorded on , changed no count of this page.

January to March 2026 is the latest closed quarter in the data. In that quarter FDA received 0 reports that name mebendazole + trichlorfon: 0 dog, 0 cat, 0 horse, 0 other or not given.

All updatesFeed of updates (RSS)

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 75 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.

  1. Abdominal pain68%51 reports
  2. Diarrhoea[diarrhea]41.3%31 reports
  3. Anorexia[not eating]18.7%14 reports
  4. Hypersalivation[drooling]16%12 reports
  5. Depression[dull, quiet or withdrawn]14.7%11 reports
  6. Death10.7%8 reports
  7. Behavioural disorder NOS[behaviour change, type not specified]6.7%5 reports
  8. Pain NOS[NOS: not otherwise specified]5.3%4 reports
  9. Dyspnoea[difficulty breathing]4%3 reports
  10. Hyperhidrosis4%3 reports
  11. Loose stool4%3 reports
  12. Recumbency[lying down and unable or unwilling to rise]4%3 reports
  13. Weakness4%3 reports
  14. Abortion2.7%2 reports
Show the next 16 signs
  1. Aggression2.7%2 reports
  2. Agitation2.7%2 reports
  3. Ataxia[unsteady, uncoordinated movement]2.7%2 reports
  4. Collapse2.7%2 reports
  5. Convulsion[seizure]2.7%2 reports
  6. Oedema of the extremities[swollen legs or paws]2.7%2 reports
  7. Trembling2.7%2 reports
  8. Apprehension1.3%1 reports
  9. Biting -aggression1.3%1 reports
  10. Blindness1.3%1 reports
  11. Bloody diarrhoea[diarrhea with blood]1.3%1 reports
  12. Bradycardia[slow heart rate]1.3%1 reports
  13. Buccal irritation1.3%1 reports
  14. Confusion1.3%1 reports
  15. Fever1.3%1 reports
  16. Gut sounds increased1.3%1 reports

The list shows 30 of 42 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)

Reports by species

The share is of all 75 reports that name mebendazole + trichlorfon. The other reports give a different species or no species.

Reports for each month, Jul 2021 to Jun 2026

Dog0 reports

No chart: no month has 5 or more reports.

Cat0 reports

No chart: no month has 5 or more reports.

Horse0 reports

No chart: no month has 5 or more reports.

Other or not given0 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
Reports that name mebendazole + trichlorfon, by the year in which FDA received them and by species
YearDogCatHorseOther or not givenAll species
199500101
199310304
199200404
199100808
199000707
19892015017
1988109010
19870024024

1995 has the reports that FDA received through Oct 1995. Download the years (CSV)

What the reports record

Outcome at the time of the report

  • Recovered/Normal0%0
  • Recovered with Sequela[recovered, with a lasting effect]0%0
  • Ongoing0%0
  • Died10.7%8
  • Euthanized0%0
  • Outcome Unknown0%0

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 75 reports that name mebendazole + trichlorfon.

A report about more than one animal can have more than one outcome.

Kind of report

  • Safety issue100%75
  • Lack of expected effectiveness0%0
  • Both safety and lack of expected effectiveness0%0
  • Manufacturing or product defect0%0
  • Other0%0
Show age, weight, breed and route

Age of the animal

  • Under 1 year1.3%1
  • 1 to 3 years4%3
  • 4 to 7 years20%15
  • 8 to 11 years8%6
  • 12 years and over8%6
  • Age not given58.7%44

Weight of the animal

  • Under 5 kg (11 lb)0%0
  • 5 to 9.9 kg (11 to 22 lb)0%0
  • 10 to 24.9 kg (22 to 55 lb)0%0
  • 25 to 44.9 kg (55 to 99 lb)2.7%2
  • 45 kg and over (99 lb and over)54.7%41
  • Weight not given42.7%32

Breed, where the report gives one breed

A breed with many animals has many reports.

Route in the report

  • Oral100%75

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

  • Telmin B

What the Green Book records give

Applications with an approval in force
2
Approved species
Equids
Dose forms
Paste, Powder
Routes
Oral, Nasogastric
Sale
OTC (over the counter), 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.

Applications in the Green Book of 2 Nov 2026, pioneer applications (NADA) first
Brand nameActive ingredientsSponsorApproved speciesApplication
Telmin B Equine WormerMebendazole, TrichlorfonIntervet, Inc.HorsesNADA 100-402
Telmin B PasteMebendazole, TrichlorfonIntervet, Inc.HorsesNADA 138-954

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

All drugs by active ingredient. Brand names A to Z

FDA pages for this drug

The site checked these addresses on . The links open in a new tab.

Cite this page

Pet Drug Reports. Mebendazole + Trichlorfon: adverse event reports that FDA received. https://petdrugreports.com/drug/mebendazole-trichlorfon/ 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 no reports in the 12 months to June 2026. It received no 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 75 reports received from January 1987 to October 1995, 100% are about a safety issue only.