Adverse effect of antidotes and chelating agents, sequela

This code signifies a long-term or residual condition resulting from a past adverse reaction to an antidote or chelating agent. It indicates that the patient experienced an undesirable effect from these medications, and that effect has now stabilized as a permanent or chronic issue.

Use this code when documenting a patient's current health problem that is a direct consequence of a previous adverse event caused by an antidote or chelating agent. This applies to conditions that are no longer acute but represent a lasting impairment or dysfunction. For example, chronic kidney damage following a severe reaction to a chelating agent.

• Always sequence this code after the code for the specific sequela (e.g., chronic kidney disease).
• Ensure documentation clearly links the current condition to a past adverse effect of an antidote or chelating agent.
• Do not use for acute adverse effects; those would be coded with the appropriate acute adverse effect code from the T50.6X series.