Poisoning by antiallerg/antiemetic, accidental, subs

This code signifies an accidental overdose or adverse reaction to antiallergic or antiemetic medications that occurred unintentionally. It specifically applies to a patient's follow-up care for the effects of such poisoning, not the initial treatment. The patient is receiving ongoing management for the complications or sequelae of the initial poisoning event.

Use this code for subsequent encounters when a patient is being treated for residual effects, complications, or ongoing monitoring related to an accidental poisoning by antihistamines, antiemetics, or other antiallergic drugs. This includes follow-up visits for organ damage, neurological sequelae, or persistent symptoms resulting from the initial unintentional overdose. It would not be used for the initial emergency room visit or acute care.

• Always assign an external cause code (e.g., X44.-) to describe the circumstances of the poisoning.
• Do not use this code for initial encounters; instead, use the "A" (initial encounter) seventh character.
• Distinguish between accidental poisoning (unintentional) and intentional self-harm or assault.