Underdosing of fentanyl or fentanyl analogs, init

This diagnosis code signifies that a patient has experienced adverse effects due to receiving an insufficient amount of fentanyl or a related synthetic opioid. This underdosing can lead to inadequate pain control, withdrawal symptoms, or a recurrence of the condition for which the medication was prescribed.

Apply this code when documentation clearly indicates that the patient's current symptoms or condition are a direct result of receiving less than the prescribed or therapeutically effective dose of fentanyl or its analogs. This includes situations where a patient self-reduced their dose, a medication error occurred, or the prescribed dose was insufficient for their needs.

• Ensure the documentation explicitly states "underdosing" or clearly describes symptoms attributable to an insufficient dose of fentanyl.
• Confirm this is the initial encounter for the underdosing event; subsequent encounters would use a different seventh character.
• Always code the specific manifestation of the underdosing (e.g., uncontrolled pain, withdrawal symptoms) first, followed by this underdosing code.