ICD-10-CM > S00-T88 > T36-T50 > T42 > T42.6 > T42.6X > T42.6X6 T42.6X6 Underdosing of other antiepileptic and sedative-hypnotic drugs Non-Billable/Non-Specific Codes T42.6X6A..., initial encounterT42.6X6D..., subsequent encounterT42.6X6S..., sequela