How one pill overwhelms a 5 kg cat's systems
Ibuprofen blocks protective prostaglandins in cats at doses far below human therapeutic levels. Your cat's stomach lining begins eroding within hours, while kidney filtration systems strain to process the drug. Unlike dogs or humans, cats lack specific liver enzymes to break it down safely. That single pill isn't diluted or spread out — it's a full assault on their small body all at once.
The other cats may seem fine now, but you'll want to verify the pill count in the bottle. Cats sometimes bat medications under furniture where they're found days later. Sweep with a flashlight, checking under appliances and along baseboards. If any pills are unaccounted for, assume they're hiding somewhere accessible rather than assuming your other cats resisted temptation.
Kidney signals that can't wait for morning
Early kidney distress shows up in subtle ways: drinking more water than usual, urinating larger amounts, or conversely — producing no urine at all. For a 5 kg cat, even 12 hours of ibuprofen exposure can cause irreversible kidney tubule damage. Don't wait for these signs; by the time you notice increased thirst, the organs may already be struggling.
Watch for unusual litter box behavior tonight. Straining to urinate or avoiding the box altogether could indicate bladder irritation from acidic urine changes. Blood in urine appears later in the toxicity timeline, but early kidney protection measures can prevent it. Your vet may recommend hospitalization with IV fluids to flush the system before filtration problems begin.
Why other cats need monitoring despite not eating the pill
While your other cats didn't ingest the ibuprofen directly, they might have licked residue off the floor or the affected cat's fur. Cats groom each other frequently, and pill coatings often leave behind bitter traces. Check their gums for unusual redness or drooling, which could indicate minor mouth irritation from tasting the medication.
More importantly, this incident reveals medication access risks in your home. Any future pills dropped on the floor become potential hazards — cats see small objects as toys. Consider storing human medications in lidded containers rather than pill organizers that cats can knock over. Childproof doesn't mean cat-proof.
The stomach ulcer timeline you're racing against
Ibuprofen begins disrupting the stomach's protective mucus layer within 60-90 minutes. By six hours post-ingestion, microscopic bleeding may start, though visible vomit with coffee-ground material (digested blood) usually appears later. Your 5 kg cat has minimal reserves to compensate for blood loss or pain-induced appetite suppression.
Vets often administer gastroprotectants like sucralfate slurry to coat ulcerated areas, but these work best when given early. Don't try home remedies like milk or bread — they won't neutralize the drug and may interfere with professional treatments. Time matters more than anything right now; every minute the pill sits in their system increases organ damage risk.
The step-by-step response, from the first minute to the vet visit, is in our Dog Poison Control Emergency Guide emergency guide.