Underdosing of other hormone antagonists, initial encounter

This code signifies that a patient has experienced an adverse effect due to receiving an insufficient amount of a hormone antagonist medication. This underdosing has led to a negative clinical outcome or failure to achieve the desired therapeutic effect during the initial period of treatment.

Apply this code when documentation clearly indicates that a patient's condition is worsening or not improving because a prescribed hormone antagonist was administered at a dose lower than therapeutically intended. This includes situations where the patient did not take enough of the medication, or the medication was prescribed or dispensed at an inadequate dose, and the patient is presenting for the first time for this specific underdosing event.

• Ensure documentation specifies "underdosing" and identifies the drug as a "hormone antagonist."
• Always use with an additional code for the specific hormone antagonist drug (from T36-T50) and a code for the nature of the adverse effect or condition resulting from the underdosing.
• The "A" seventh character indicates an initial encounter for this specific underdosing event.