Adverse effect of antitussives, subsequent encounter

This code indicates a patient is experiencing an unintended and harmful reaction to a medication classified as an antitussive, such as dextromethorphan or codeine, during a follow-up visit. The adverse effect is not due to poisoning, underdosing, or an allergic reaction, but rather a known side effect of the drug when properly administered.

Apply this code when a patient presents for ongoing management or evaluation of an adverse effect from an antitussive that was previously initiated. This includes situations where the patient is being monitored for resolution of symptoms or adjusting treatment due to the adverse reaction.

• Always sequence this code after the code for the specific adverse effect (e.g., nausea, dizziness).
• Ensure the encounter is truly "subsequent" and not the initial presentation of the adverse effect.
• Distinguish adverse effects from poisoning (T48.3X1-T48.3X4), underdosing (T48.3X6-), or allergic reactions.