Poisoning by oth drug/meds/biol subst, accidental, init

This code signifies an accidental overdose or adverse reaction to a drug, medication, or biological substance not specifically classified elsewhere. It indicates that the patient's exposure was unintentional, such as taking the wrong dose, mistaking one medication for another, or an unexpected adverse effect. This is for the initial presentation of the poisoning event.

Apply this code when a patient presents with symptoms of poisoning due to an accidental exposure to a substance that doesn't have a more specific ICD-10-CM code. Examples include an accidental overdose of an over-the-counter medication, an unintentional ingestion of a household chemical mistaken for medicine, or an unexpected severe allergic reaction to a new biologic therapy.

• Always sequence this code first if it is the primary reason for the encounter.
• Requires an additional code to identify the specific drug or substance (e.g., from categories T36-T50).
• Ensure the "A" seventh character is used only for the initial encounter for treatment of the poisoning.