Underdosing of antimycobacterial drugs, initial encounter

This code indicates a patient is experiencing adverse effects or complications due to receiving an insufficient amount of antimycobacterial medication. This underdosing can lead to treatment failure, disease progression, or the development of drug resistance in conditions like tuberculosis or leprosy.

Apply this code when a patient presents for initial treatment of a condition directly resulting from or exacerbated by inadequate antimycobacterial drug dosage. This includes situations where the patient did not take enough medication, the prescribed dose was too low, or there was an issue with drug absorption.

• Always assign an additional code for the specific adverse effect or complication resulting from the underdosing.
• Use a secondary code from categories A15-A19 for tuberculosis or A30 for leprosy, if applicable, to specify the underlying mycobacterial infection.
• This "initial encounter" seventh character is used for the period when the patient is receiving active treatment for the underdosing complication.