Acetaminophen overdose treatment when acetaminophen levels are not available
The Ontario Poison Centre has become aware that several hospitals have been unable to secure enough reagents/cartridges to be able to process acetaminophen concentrations. Acetaminophen levels are now “send outs” in these communities with a turnaround time of 3-5 days.
This may influence care and prompt us to change our recommendations as to whom to treat & when to stop.
Should a health care facility (HCF) be unable to process an acetaminophen level in a timely fashion on site, an accurate history of the ingestion is paramount. IF the history of ingestion is such that the patient could have taken a toxic dose (the amount available to the patient was > 10g or 200 mg/kg), then empiric treatment with n-acetylcysteine (NAC) should be started. The usual loading dose over 4 hours, followed by typical dosing maintenance should be recommended. To be conservative, these patients should receive a total of 24 hours of NAC infusion. IF the facility can do other labs, stopping NAC at the end of 24 hours will require that:
- the AST OR ALT is under 100 IU,
- the patient is not acidemic & well, and
- the INR <= 2.0.
We would still recommend that the 4 hour acetaminophen level be sent out, and an acetaminophen level at the end of the 24 hour infusion. The HCF should be able to contact that patient (with a telephone number) once levels are back if unexpected results are reported.
Margaret Thompson, MD
Medical Director, Ontario & Manitoba Poison Centre
(serving the Health Care providers in Nunavut)