non-elective
/ˌnɒnɪˈlɛktɪv/adjective
1Of a post, committee, etc.: not filled by election. Of a person: not chosen by election.
2That is mandatory; not discretionary; specifically (a) Education (of a course of study) prescribed; (b) Medicine (of a treatment or procedure) medically necessary.
Origin
Mid 19th century; earliest use found in National Era. From non- + elective.