ICD-10-CM > S00-T88 > T36-T50 > T43 > T43.0 > T43.01 > T43.016 T43.016 Underdosing of tricyclic antidepressants Non-Billable/Non-Specific Codes T43.016A..., initial encounterT43.016D..., subsequent encounterT43.016S..., sequela