Drug · single active ingredient
Zoalene: adverse event reports
All products with this active ingredient · 4 FDA-approved applications in the Green Book
- Mostly chicken reports
- Oral route most often
- Brands masked by FDA
45 adverse event reports in FDA's database list a drug whose active ingredient is recorded as zoalene. The earliest was received in March 2000, the latest in February 2026. The Green Book lists 4 FDA-approved applications with this single active ingredient.
openFDA masks the brand and manufacturer in every report, so these figures describe the ingredient across all products and cannot be attributed to a brand.
In the 12 months to March 2026, 3 reports named it, down 25% from 4 in the 12 months before. Recent months are provisional: fDA posts reports quarterly with a delay of three to six months, so the newest months are incomplete and usually grow in later releases. Over its whole reporting history that is about 2 reports a year and 0% of all 1,357,245 reports (3.9% of all chicken reports). How many animals received it is not published, so a count says nothing about how often a problem occurs per dose.
Reporters most often listed death (64.4%), lack of efficacy - NOS (37.8%) and lack of efficacy (protozoa) - Coccidia (20%). A report can list several signs, so shares add to more than 100%; 29 different terms appear across these reports.
93.3% of reports concern chickens. Not every report describes illness: 64.4% were filed wholly or partly as lack of expected effectiveness. Of reports that state seriousness, 86.4% were classed as serious, and 80% of all reports record a death or euthanasia as an outcome, as reported. FDA has not necessarily determined whether any drug played a part.
Monthly reports by species, five years
Reports by the month FDA received them. Each panel has its own scale; the peak month is printed at the top right. The newest months are incomplete because FDA posts reports with a delay of three to six months.
Reports by year received
2026 covers reports received through March 2026 only.
Signs listed in reports
share of zoalene reports listing the termall chicken reports
- Death64.4%29
- Lack of efficacy - NOS[the product did not have the expected effect]37.8%17
- Lack of efficacy (protozoa) - Coccidia[the product did not have the expected effect: coccidia]20%9
- Ataxia[unsteady, uncoordinated movement]8.9%4
- Lethargy[unusually tired or inactive]8.9%4
- Ineffective, coccidia[legacy FDA term: the product did not have the expected effect (coccidia)]6.7%3
- Central nervous system depression4.4%2
- Decreased drinking4.4%2
- Somnolence4.4%2
- Unexplained death4.4%2
- Death by euthanasia[the animal was euthanized]2.2%1
- Dermatitis[inflamed skin]2.2%1
- Downer animal2.2%1
- Enteritis2.2%1
- Gangrene2.2%1
- Low weight gain2.2%1
- NT - Abnormal necropsy finding NOS[NOS: not otherwise specified]2.2%1
- Necropsy performed2.2%1
- Neuromuscular disorder NOS[NOS: not otherwise specified]2.2%1
- PR-heart, lesion(s)[legacy FDA term: lesions found in the heart]2.2%1
- PR-liver, lesion(s)[legacy FDA term: lesions found in the liver]2.2%1
- PR-pancreas, lesion(s)[legacy FDA term: lesions found in the pancreas]2.2%1
- PR-spleen, lesion(s)[legacy FDA term: lesions found in the spleen]2.2%1
- Recumbency[lying down and unable or unwilling to rise]2.2%1
- Reluctant to move2.2%1
- Underdose[less than the labelled amount was given]2.2%1
- Weakness2.2%1
Top 29 of 29 coded terms (VeDDRA, the veterinary reporting dictionary; plain-language gloss in brackets). One report can list several terms. The ticks show how often the same term appears in a wider pool of reports; they describe the reports, and FDA cautions that such figures cannot be used to estimate risk or to compare one product with another. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand.
Outcomes and report types
Outcome recorded in the report
What kind of report it was
Coloured bar: reports naming zoalene. Grey bar: all 1,357,245 reports in the database. Outcomes are the status at the time of the last report, as stated by the reporter; a report covering several animals can carry more than one outcome. FDA has not necessarily determined whether any drug played a part in any outcome.
Species and breeds in the reports
Breed shares follow how common each breed is. Crossbred animals and reports with no breed stay in the species figure only.
Age, weight and route
Age of the animal
Weight of the animal
Route of administration stated in reports: oral (45).
In context
| Measure | Zoalene | All chicken reports | All reports |
|---|---|---|---|
| Reports | 45 | 1,073 | 1,357,245 |
| Share of that pool's reports naming this drug | — | 3.9% | 0% |
| Classed serious, of reports stating it | 86.4% | 58.2% | 38.6% |
| Death or euthanasia recorded, per 1,000 reports | 800 | 524 | 63.8 |
| Filed as lack of expected effectiveness (wholly or partly) | 64.4% | — | 23% |
| Top term, share of reports | Death 64.4% | 38% | — |
This set accounts for 100% of all reports naming zoalene, so no separate ingredient column is shown. Shares are of reports, not of animals treated. The number of doses sold is not public, so none of these figures is a rate of occurrence, and differences between columns reflect which animals receive a drug and who reports as much as anything else.
FDA-approved products containing zoalene (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 1 Oct 2026; nothing on this page says which of these products, if any, a report concerned.
| Trade name | Active ingredients | Sponsor | Approved for | Application |
|---|---|---|---|---|
| Zoamix Type A Medicated Article | Zoalene | Phibro Animal Health Corp. | Chickens, Turkeys | NADA 011-116 |
| Zoalene 90 Medicated Coccidiostat | Zoalene | Phibro Animal Health Corp. | Chickens, Turkeys | NADA 013-747 |
| ZoaShield 25% | Zoalene | Elanco US Inc. | Chickens, Turkeys | ANADA 200-690 |
| Broiler Premix 18580; Turkey Premix 18581 Medicatedapproval voluntarily withdrawn | Zoalene | Roche Vitamins, Inc. | — | NADA 042-756 |
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 zoalene reports
How many adverse event reports has FDA received for zoalene?
45 reports record a drug with zoalene as its active ingredient in the openFDA release of 28 Sep 2026, covering reports received through March 2026. 3 of them arrived in the latest 12 months.
Which brand 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 lists 4 approved applications with this ingredient alone; the reference list on this page names them without any counts.
What signs are reported most often?
death (64.4%), lack of efficacy - NOS (37.8%), lack of efficacy (protozoa) - Coccidia (20%), ataxia (8.9%) and increased mortality rate (8.9%). These are the coded terms listed in reports; several can appear in one report, and a term's presence is not a finding that the drug was responsible.
Which species and breeds appear in these reports?
chicken (93.3%) and turkey (6.7%).
Are reports rising?
3 reports in the 12 months to March 2026, down 25% from 4 in 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. Counts also move with sales, publicity and time on the market.
Do these reports show that zoalene harms pets?
Report counts 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." FDA also notes that commonly used products may have more reports simply because more animals receive them.
Are these the side effects of zoalene?
They are signs listed in reports, not an established list of side effects. The adverse reactions observed in studies are printed on each product's FDA-approved label, which a veterinarian can go through with you. This page is a record of what was reported to FDA.
How do I report a problem with an animal drug?
FDA asks owners and veterinarians to call the drug company first (the number is on the label); companies must pass reports to FDA. Reports can also go directly to FDA on Form FDA 1932a. 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 1 Oct 2026. Drug entries are grouped by the active ingredients their unmasked ingredient field discloses; the application number that records also carry is not used. 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.