Adverse effect of unsp drug/meds/biol subst, subs

This code signifies a patient experiencing a negative or unintended reaction to a medication, biological substance, or other drug, where the specific substance causing the reaction is not documented. The "subsequent encounter" designation indicates that the patient is receiving follow-up care for this adverse effect after the initial treatment.

Use this code when a patient presents for ongoing management of an adverse drug reaction, and the medical record does not specify the particular drug or substance responsible. This is appropriate for follow-up visits, medication adjustments, or monitoring of the adverse effect's resolution.

• Always attempt to identify the specific drug or substance causing the adverse effect to use a more precise code.
• Ensure the documentation clearly indicates this is a follow-up encounter for the adverse effect, not the initial presentation.
• Pair this code with codes for the specific manifestation of the adverse effect (e.g., rash, nausea).