ICD-10-CM > S00-T88 > T36-T50 > T43 > T43.3 > T43.3X > T43.3X6 T43.3X6 Underdosing of phenothiazine antipsychotics and neuroleptics Non-Billable/Non-Specific Codes T43.3X6A..., initial encounterT43.3X6D..., subsequent encounterT43.3X6S..., sequela