Poisoning by hydantoin derivatives

This code signifies an adverse reaction or overdose resulting from exposure to hydantoin derivatives, a class of anticonvulsant medications. This includes both accidental and intentional ingestions, as well as therapeutic misadventures leading to toxic effects. Patients may present with neurological symptoms, gastrointestinal distress, or other systemic manifestations of toxicity.

Assign this code when documentation clearly indicates poisoning by a hydantoin derivative, such as phenytoin (Dilantin), fosphenytoin, or ethotoin. This code is appropriate for cases of acute overdose, chronic toxicity due to accumulation, or adverse effects from drug interactions. Supporting documentation should detail the substance involved, the circumstances of the poisoning, and the patient's clinical presentation.

• Always code the specific manifestation of the poisoning first, followed by this code to identify the causative agent.
• Distinguish between poisoning (adverse effect, overdose) and adverse effects in therapeutic use (e.g., allergic reaction at therapeutic dose), which would typically be coded differently.
• Review documentation carefully to ensure the substance is indeed a hydantoin derivative, as other anticonvulsants fall into different drug classes.