Adverse effect of agents primarily affecting GI sys, subs

This code signifies a harmful or unintended reaction to a substance that primarily impacts the digestive system, occurring during a follow-up visit for the condition. It indicates that the patient is receiving ongoing care for a gastrointestinal issue caused by an adverse drug or chemical effect.

Apply this code when documenting subsequent encounters for patients experiencing gastrointestinal symptoms such as nausea, vomiting, diarrhea, constipation, or abdominal pain that are confirmed to be an adverse effect of a medication, chemical, or other substance. This is appropriate for follow-up appointments where the patient's condition is being monitored or managed after the initial adverse event.

• Always sequence this code after the code for the specific adverse effect (e.g., K52.1 for toxic gastroenteritis).
• Ensure the documentation clearly states the adverse effect is related to a substance and that it's a subsequent encounter.
• Do not use this code for poisoning, underdosing, or allergic reactions, as those have distinct coding categories.