ICD-10-CM > S00-T88 > T36-T50 > T48 > T48.1 > T48.1X > T48.1X6 T48.1X6 Underdosing of skeletal muscle relaxants [neuromuscular blocking agents] Non-Billable/Non-Specific Codes T48.1X6A..., initial encounterT48.1X6D..., subsequent encounterT48.1X6S..., sequela