ICD-10-CM > S00-T88 > T36-T50 > T42 > T42.5 > T42.5X > T42.5X6 T42.5X6 Underdosing of mixed antiepileptics Non-Billable/Non-Specific Codes T42.5X6A..., initial encounterT42.5X6D..., subsequent encounterT42.5X6S..., sequela