Cal. Health & Safety Code § 1342.75

(a) Notwithstanding any other law, a group or individual health care service plan offering an outpatient prescription drug benefit shall provide coverage for at least one medication approved by the United States Food and Drug Administration in each of the following categories without prior authorization, step therapy, or utilization review:
1. (1) Medication for the reversal of opioid overdose, including a naloxone product or another opioid antagonist.
2. (2) Medication for the detoxification or maintenance treatment of a substance use disorder, including a daily oral buprenorphine product.
3. (3) A long-acting buprenorphine product.
4. (4) A long-acting injectable naltrexone product.
(b) This section does not prohibit a health care service plan from selecting an AB-rated generic equivalent, biosimilar, as defined in Section 262(i)(2) of Title 42 of the United States Code, or interchangeable biological product, as defined in Section 262(i)(3) of Title 42 of the United States Code, to meet the requirements of subdivision (a).