Why two tablets overwhelm a 3 kg cat
A single prenatal vitamin often contains 60–65 mg of elemental iron, meaning your cat ingested over 120 mg. For perspective, the toxic threshold starts at just 20 mg/kg—your cat’s tiny body took in 40 mg/kg, double the danger line. Iron doesn’t just irritate the stomach; it floods the bloodstream, overwhelming the liver’s ability to process it. Even if vomiting seems to remove some, absorbed iron continues damaging cells.
The corrosive effect begins in the stomach lining, causing pain and black, tarry stools from internal bleeding. But the bigger threat is hepatic injury: iron accumulates in the liver, generating free radicals that destroy tissue. This isn’t a "wait and see" situation—aggressive veterinary treatment with chelation therapy may be needed to bind the iron before it causes irreversible harm.
The deceptive two-phase crisis ahead
Within 6 hours, you might see vomiting, diarrhea, or lethargy as the iron attacks the GI tract. Some cats briefly appear to recover after 12–24 hours as symptoms ease, but this is a false calm. Phase two hits as iron concentrates in organs, leading to collapse, jaundice (yellow gums), seizures, or coma. By then, treatment options narrow drastically.
Time matters more than visible signs. Blood tests checking iron levels and liver enzymes should begin immediately, even if your cat seems stable. IV fluids help protect the kidneys, and medications like gastroprotectants can reduce bleeding, but delaying care until phase two often means facing liver failure or death.
Why your other cats dodged a bullet
It’s fortunate the other cats ignored the vitamins—smaller ingestions still carry risk, but two tablets would have been equally dire for them. Cats lack the enzymes to efficiently excrete excess iron, so their bodies store it toxically. Unlike dogs, they’re also less likely to chew odd objects, which may explain why only one investigated.
That said, monitor the others for any unusual licking or lethargy. While they probably didn’t ingest anything, iron powder from broken tablets can stick to paws and be groomed off later. Wipe their faces and paws with a damp cloth, and check for leftover tablet fragments in their sleeping areas.
What to do in the next 30 minutes
Call your nearest emergency vet—describe "iron overdose in a 3 kg cat" clearly, as not all clinics stock the antidote (deferoxamine). If they can’t administer it, they’ll direct you to a facility that can. Bring the vitamin bottle to confirm iron content; generic terms like "prenatal" aren’t enough—vets need the milligrams per tablet.
Do not induce vomiting or give food/water unless instructed. Iron corrodes the esophagus when regurgitated, and fluids can accelerate absorption. Wrap your cat in a towel for safe transport—pain may make them restless or aggressive. Note any timestamps: when you found the tablets, any vomiting episodes, or changes in breathing. Every detail helps the vet prioritize treatment.
The step-by-step response, from the first minute to the vet visit, is in our Iron Supplements & Prenatal Vitamins emergency guide.