Why three tablets overwhelm a 2.2 kg body
A Yorkshire terrier this size has no buffer against concentrated iron. Prenatal vitamins pack 27–65 mg per tablet — three tablets deliver up to 195 mg total, which translates to nearly 90 mg per kilogram of your dog's weight. That's well into the danger zone where iron starts burning through stomach tissue within hours, then floods the bloodstream to attack the liver.
Watch for vomiting (possibly with blood), diarrhea, or sudden lethargy in the next six hours. The deceptive phase where symptoms seem to ease doesn't mean safety — it's when iron shifts from gut damage to systemic poisoning.
The first actions for rapid absorption
Time matters more than you'd think with iron. These tablets were likely chewed, not swallowed whole, which speeds up dissolution in the stomach. Your vet may use binders to trap iron before it absorbs, but this only works if done early — after two hours, most damage control shifts to protecting organs.
Bring the vitamin bottle to the clinic. The exact iron formulation (ferrous fumarate vs. ferrous sulfate) changes how aggressively it needs treatment. Blood tests at 12 and 24 hours post-ingestion will track liver enzyme spikes.
Why small breeds crash faster
That 2.2 kg frame has minimal fat stores to dilute toxins. Iron's corrosive effects hit harder in compact bodies — ulcerations can perforate the stomach wall quicker than in larger dogs. Yorkshire terriers also tend to have sensitive gastrointestinal systems, amplifying the vomiting-diarrhea cycle.
Even if your dog seems stable after vomiting once, don't wait. Small dogs dehydrate dangerously fast when nauseous, and iron poisoning can suppress their urge to drink water despite needing fluids urgently.
The critical 48-hour observation window
Iron poisoning unfolds in distinct phases. Initial vomiting within 6 hours gives way to apparent improvement for 12–24 hours — this is when owners often relax, but it's actually the calm before liver damage manifests. Bloodwork around the 36-hour mark catches rising ALT and AST enzymes before jaundice or collapse occur.
Your vet will likely hospitalize for IV fluids containing liver protectants. Ask about monitoring for hemorrhagic gastroenteritis — iron thins the blood over time, making bloody stools a late-stage red flag.
The step-by-step response, from the first minute to the vet visit, is in our Iron Supplements & Prenatal Vitamins emergency guide.