A Numbers Game That Doesn’t Add Up
Elanco claims adverse reactions to Zorbium® occur in “about 1 in 10,000” cats. Let’s take them at their word and see what the numbers should look like—and why they don’t match what we’re actually seeing in FDA data.
If Elanco’s “1 in 10,000” Rate Were True
Here’s what the FDA adverse event database should show:
To generate 2,800 adverse events at Elanco’s claimed rate of 1 in 10,000, Zorbium® would need to have been used in 28 million cats.
That would make Zorbium® one of the most widely-used veterinary drugs in history. Administered to roughly half of all cats in the United States.
The Manufacturing Reality Check
But here’s what we know about actual production capacity:
Zorbium® is produced exclusively by Ivy Animal Health, a small facility in Kansas with approximately 60 employees.* When Elanco acquired Ivy in 2007, it was a cattle implant manufacturer focused on “beef-producing customers.” The facility underwent a complete business transformation to manufacture a cat pain medication—a dramatic pivot that suggests specialized, limited production.
Using pharmaceutical industry benchmarks, a 60-employee facility could reasonably produce 100,000-330,000 units over the 33 months since FDA approval. Even the most generous production estimates fall far short of the millions needed to support Elanco’s safety claims.
What the FDA Data Actually Shows
The FDA’s Veterinary Adverse Event Reporting System reveals:
- 2,800 total adverse events reported for Zorbium®
- 301 confirmed deaths
The Numbers Game: Working Backward
Let’s work backward from Elanco’s claim:
If Elanco is right about 1 in 10,000:
- 2,800 adverse events ÷ 10,000 = 28 million doses administered
- That’s 38% of all cats in America (out of ~74 million total cats).
- That would mean tens of thousands of veterinary clinics, each equipped for DEA Schedule III handling, are quietly and consistently administering Zorbium® at a rate that surpasses the launch of any cat drug in history.
- Every participating clinic would need Schedule III storage, naloxone on hand, and detailed record-keeping.
- It would make Zorbium® the most successful veterinary drug launch ever.
If production estimates are realistic (100k-330k units):
- Adverse event rate: 1 in 36 to 1 in 118 cats
- 85 to 280 times higher than Elanco’s public claims
And here’s the deadliest statistic from FDA data: When cats do have adverse reactions to Zorbium®, 1 in every 9 cats dies. That’s not a minor side effect—that’s a life-threatening outcome rate of more than 11%.
The Telltale Silence
Here’s what’s revealing: when pharmaceutical companies achieve major market penetration, they announce it. Sales milestones become marketing tools and investor talking points.
Elanco’s silence on Zorbium® sales figures, combined with their exclusive manufacturer’s limited production capacity, suggests volumes far below what would be needed to support their “1 in 10,000” safety narrative.
A Pattern of Concealment
In 2023, Ivy Animal Health received three “Voluntary Action Indicated” classifications from the FDA—regulatory speak for “we found problems, fix them voluntarily or we’ll take official action.”* Additionally, Elanco itself has received FDA warning letters for various compliance issues.*
The Bottom Line
The math doesn’t work. Either:
- Elanco has achieved unprecedented market penetration with a drug manufactured at a small facility that underwent a complete business transformation, reaching 28 million cats with no fanfare or sales announcements, OR
- Their “1 in 10,000” safety claim vastly understates the real risk to cats receiving this medication.
The adverse event data doesn’t lie. The production capacity is limited. The facility has documented compliance issues.
Pet owners deserve the real numbers, not marketing spin that makes a drug appear 85-280 times safer than it actually is.
*Disclaimers:
- *Based on available public information indicating Ivy Animal Health as the exclusive manufacturer listed in FDA documentation
- *FDA Voluntary Action Indicated classifications were related to veterinary pharmaceutical manufacturing; specific details not publicly available
- *Elanco warning letters relate to various products and facilities, not necessarily Zorbium® specific
Analysis based on FDA Veterinary Adverse Event Reporting System data through 33 months post-approval, pharmaceutical manufacturing industry benchmarks, and publicly available facility information. Production estimates represent reasonable ranges based on facility size and comparable operations. Posted 7.29.25 If this research helps with your FOIA requests, please consider citing this page as a source.