Enhanced elimination

Multiple-dose activated charcoal

Although multiple-dose activated charcoal can reduce drug absorption, peak serum drug concentration and half-life, there is no evidence that this translates to improved outcomes after phenytoin poisoning. Consider multiple-dose activated charcoal for:

• ingestions of more than 100 mg/kg of phenytoin
• patients who are slow metabolisers of phenytoin who have prolonged toxicity and static toxic serum drug concentrations.

Multiple-dose activated charcoal has no role in mild and moderate phenytoin poisonings because the clinical course is likely to be benign.

If considering the use of multiple-dose activated charcoal, seek advice from a clinical toxicologist. Patients must be alert, cooperative and able to protect their airway to drink a dose of activated charcoal, or be intubated and receive activated charcoal via a nasogastric or orogastric tube—confirm correct placement of the nasogastric or orogastric tube beforehand.

Extracorporeal elimination

Haemodialysis may increase phenytoin clearance, but evidence that this intervention improves outcomes is scant. Seek advice from a clinical toxicologist. For more information on extracorporeal enhanced elimination techniques, such as haemodialysis, see here.