Pet Drug Reports

Phenobarbitaladverse event reports that FDA received

Active ingredient

The Green Book lists no brand name for exactly this active ingredient.

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 December 1999 to June 2026, FDA received 1,680 adverse event reports that name a drug with phenobarbital as its active ingredient. Of the 1,680 reports, 1,543 (91.8%) are about dogs. 130 reports are about cats (7.7%).

In January to March 2026, FDA received 31 reports that name this drug. The signs that appear in the largest number of the 1,680 reports are "Seizure NOS", "Lethargy" and "Vomiting". A report is not proof that a drug caused a sign.

Reports that name this drug fell by 18.9% 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 91.8% of the reports that name this drug, and 72.6% of all reports.

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 31 reports that name phenobarbital: 23 dog, 8 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 1,680 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. Seizure NOS[seizure, type not specified]37.3%627 reports
  2. Lethargy[unusually tired or inactive]13.6%228 reports
  3. Vomiting10.1%170 reports
  4. Death by euthanasia[the animal was euthanized]7.3%122 reports
  5. Other abnormal test result NOS[abnormal laboratory result, type not specified]6.2%104 reports
  6. Ataxia[unsteady, uncoordinated movement]6%101 reports
  7. Lack of efficacy - NOS[the product did not have the expected effect]6%101 reports
  8. Emesis[vomiting]5.5%93 reports
  9. Diarrhoea[diarrhea]5.5%92 reports
  10. Death4.9%82 reports
  11. Behavioural disorder NOS[behaviour change, type not specified]4.8%80 reports
  12. Anorexia[not eating]4.5%76 reports
  13. Elevated serum alkaline phosphatase (SAP)[a liver and bone enzyme above the normal range]4.3%73 reports
  14. Elevated alanine aminotransferase (ALT)[a liver enzyme above the normal range]3.8%63 reports
Show the next 16 signs
  1. Increased seizure frequency3.7%62 reports
  2. Weight loss3.5%59 reports
  3. Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]3.3%55 reports
  4. Not eating3%51 reports
  5. Tremor2.7%46 reports
  6. Panting2.6%43 reports
  7. Weakness2.6%43 reports
  8. Vocalisation[crying out or unusual noise]2.2%37 reports
  9. Decreased appetite2.1%35 reports
  10. Underdose[less than the labelled amount was given]2.1%35 reports
  11. Twitching2%34 reports
  12. Anaemia NOS[low red blood cell count]2%33 reports
  13. Disorientation2%33 reports
  14. Grand mal seizure1.9%32 reports
  15. Limb weakness1.9%32 reports
  16. Overdose[more than the labelled amount was given]1.8%31 reports

The list shows 30 of 1,000 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)

Reports by species

  • Dog91.8%1,543
  • Cat7.7%130
  • Other Canids0.1%1

The share is of all 1,680 reports that name phenobarbital. The other reports give a different species or no species.

Reports for each month, Jul 2021 to Jun 2026

Dog442 reports. Largest count in one month: 19 (Apr 2024)
Cat62 reports. Largest count in one month: 5 (Jan 2026)
Horse0 reports

No chart: no month has 5 or more reports.

Other or not given2 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 phenobarbital, by the year in which FDA received them and by species
YearDogCatHorseOther or not givenAll species
202650140064
20251141102127
20241261700143
202365140079
20225450059
20218240086
20209250097
20198580194
2018101900110
2017130600136
201698800106
2015101301105
2014110600116
2013159803170
20121411000151
20111920021
201030003
200910001
200810001
200710001
200620002
200520002
200410001
200320002
200210001
200110001
199910001

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/Normal29.9%503
  • Recovered with Sequela[recovered, with a lasting effect]3.9%65
  • Ongoing28.8%484
  • Died5.3%89
  • Euthanized6.9%116
  • Outcome Unknown24%404

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 1,680 reports that name phenobarbital.

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

Kind of report

  • Safety issue84.3%1,416
  • Lack of expected effectiveness6.6%111
  • Both safety and lack of expected effectiveness6.5%110
  • Manufacturing or product defect2.5%42
  • Other0.1%1

1,615 reports say if the event was serious. 61.8% 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 year1.3%21
  • 1 to 3 years14.2%239
  • 4 to 7 years30.4%511
  • 8 to 11 years30.8%517
  • 12 years and over20.7%347
  • Age not given2.7%45

Weight of the animal

  • Under 5 kg (11 lb)14.9%251
  • 5 to 9.9 kg (11 to 22 lb)23.3%392
  • 10 to 24.9 kg (22 to 55 lb)24.1%405
  • 25 to 44.9 kg (55 to 99 lb)26.6%447
  • 45 kg and over (99 lb and over)6%100
  • Weight not given5.1%85

Breed, where the report gives one breed

A breed with many animals has many reports.

Route in the report

  • Oral56.3%945
  • Intravenous0.8%14
  • Other0.1%1
  • Parenteral0.1%1
  • Rectal0.1%1
  • Subcutaneous0.1%1

Each bar is on a scale of 0 to 100%.

Approved animal drugs with this active ingredient (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.

The Green Book lists no approved animal drug with this active ingredient. FDA also receives reports for human drugs and compounded drugs that veterinarians prescribe.

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. Phenobarbital: adverse event reports that FDA received. https://petdrugreports.com/drug/phenobarbital/ Source: FDA Center for Veterinary Medicine, openFDA Animal and Veterinary adverse event reports, export of . Reports received through .

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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 lists no brand name for exactly this active ingredient.

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 116 reports in the 12 months to June 2026. It received 143 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 1,680 reports received from December 1999 to June 2026, 84.3% are about a safety issue only. 13.2% are about a lack of expected effectiveness, alone or with a safety issue. 2.5% are about a defect of the product or its package.