Medicine Section

ACETAMINOPHEN

What happens and How will you manage and How do they get access?

• Often administered to sick cats by their owners
• Acetaminophen has a narrow margin of safety in cats. One adult tablet (325 to 500 mg) could be lethal.
• Clinical signs such as
  • Depression
  • Vomiting
  • Dyspnea
    • brown discoloration of the mucous membranes and blood due to methemoglobinemia
    • respiratory distress
  • Swelling of the face and paws
    • Hepatic necrosis can develop at almost any level of exposure.
• Treatment
  • Induce emesis and activated charcoal administered
  • Start oxygen therapy combined with a blood transfusion or polymerized bovine hemoglobin solution administrationfor methhaemoglobinemia
  • Oral administration of N-acetylcysteine solution is diluted to a 5% concentration with 5% dextrose or sterile water; this will yield a 50-mg/ml solution.
  • The loading dose is 140 mg/kg followed by 70 mg/kg every six hours for seven additional doses.
  • Intravenous fluids
  • Cimetidine (to inhibit CP450 liver enzymes that activate acetaminophen to the toxic metabolite), and ascorbic acid, which may be used to help reduce methemoglobin to hemoglobin.
  • The prognosis in these cases is fair to guarded.