Monensin (Rumensin, Sweetlix Rumensin Pressed Block): adverse event reports that FDA received

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 4,867 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. Death48%2,338 reports
2. Anorexia[not eating]12.8%621 reports
3. Diarrhoea[diarrhea]12.5%608 reports
4. Accidental exposure[exposure that was not intended]10.1%490 reports
5. Lack of efficacy (protozoa) - Coccidia[the product did not have the expected effect: coccidia]9.9%484 reports
6. Milk production decrease6.9%337 reports
7. Recumbency[lying down and unable or unwilling to rise]6.9%334 reports
8. Inappropriate preparation of medication6.5%316 reports
9. Alteration of milk quality6.2%301 reports
10. Decreased appetite4.2%205 reports
11. Loose stool4.1%198 reports
12. Lack of efficacy - NOS[the product did not have the expected effect]3.9%190 reports
13. Not eating3.9%189 reports
14. Ruminal bloat3.6%174 reports

The list shows 30 of 859 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)

Reports by species

• Cattle70.1%3,412
• Turkey8.2%399
• Horse6.3%306
• Chicken3.9%191
• Sheep2.2%109
• Goat1.7%82

The share is of all 4,867 reports that name monensin. The other reports give a different species or no species.

Reports for each month, Jul 2021 to Jun 2026

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

2026 has the reports that FDA received through Jun 2026. Download the years (CSV)

What the reports record

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

Other pages with this ingredient

A report names a drug by its set of active ingredients. Each set has its own page. The list is in order of name.

• Monensin + Tylosin
• Monensin + Tylosin Phosphate

Next in the A to Z list

• Mirtazapine
• Misoprostol
• Molidustat
• Mometasone Furoate Monohydrate + Orbifloxacin + Posaconazole
• Moxidectin
• Moxidectin + Praziquantel

All drugs by active ingredient. Brand names A to Z

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 095-735The FDA record of the application for Rumensin 90, Rumensin 113.
• Green Book record of NADA 109-471The FDA record of the application for Sweetlix Rumensin Pressed Block.
• Green Book record of NADA 115-581The FDA record of the application for MoorMan's Mintrate Blonde Block RU, MoorMan's Mintrate Red Block RU.
• Green Book record of NADA 118-509The FDA record of the application for Pasture Gainer Block 20 R350, Pasture Gainer Block 20 R350 No SE, Pasture Gainer Block 37 R350, Pasture Gainer Block 37 R350 No SE.
• Green Book record of NADA 119-253The FDA record of the application for Cattle Block RU-MIN.
• Green Book record of NADA 141-621The FDA record of the application for Crystalyx IONO-LYX R800.
• Animal Drugs @ FDAThe search page of the Green Book, the FDA list of approved animal drugs.

The site checked these addresses on 2 Oct 2026. The links open in a new tab.

Cite this page

Pet Drug Reports. Monensin: adverse event reports that FDA received. https://petdrugreports.com/drug/monensin/ Source: FDA Center for Veterinary Medicine, openFDA Animal and Veterinary adverse event reports, export of 30 Oct 2026. Reports received through 26 Jun 2026.

Where the data come from

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 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 147 reports in the 12 months to June 2026. It received 125 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 4,867 reports received from January 1987 to June 2026, 86.4% are about a safety issue only. 10.5% are about a lack of expected effectiveness, alone or with a safety issue. 3.1% are about a defect of the product or its package.