Poisoning by antidotes and chelating agents, not elsewhere classified

This code signifies an adverse reaction or toxic effect resulting from the administration of medications specifically designed to counteract poisons or remove heavy metals from the body. It describes an unintended and harmful outcome from antidotes (e.g., naloxone, flumazenil) or chelating agents (e.g., EDTA, deferoxamine).

Use this code when documentation clearly indicates a patient has experienced poisoning or an adverse effect from an antidote or chelating agent, rather than the original substance being treated. This typically occurs when the medication is given in excessive doses, inappropriately, or the patient has an idiosyncratic reaction. Documentation should specify the antidote or chelating agent involved and the resulting toxic effects.

• Always sequence this code as a primary diagnosis when the poisoning by the antidote/chelating agent is the reason for the encounter.
• Do not confuse with poisoning by the original toxic substance; this code is specifically for the adverse effect of the treatment.
• Look for documentation specifying "adverse effect of," "overdose of," or "toxic reaction to" a named antidote or chelating agent.