Adverse effect of antidotes and chelating agents, subs

This code signifies a patient experiencing an unintended, harmful reaction to a medication administered to counteract a poison or remove heavy metals from the body. It specifically applies to adverse effects of antidotes or chelating agents, not the original poisoning or metal toxicity itself.

Apply this code when a patient presents for follow-up care or management of symptoms directly attributable to an adverse effect from an antidote or chelating agent. Examples include renal dysfunction after chelation therapy, or a hypersensitivity reaction to an antidote.

• Always sequence this code after the code for the specific adverse effect (e.g., rash, acute kidney injury).
• Do not use this code for therapeutic drug monitoring or expected side effects.
• Ensure documentation clearly links the adverse effect to the antidote/chelating agent and indicates a subsequent encounter.