California Code, Labor Code - LAB § 4600.2

(a) Notwithstanding Section 4600, if a self-insured employer, group of self-insured employers, insurer of an employer, or group of insurers contracts with a pharmacy, group of pharmacies, or pharmacy benefit network to provide medicines and medical supplies required by this article to be provided to injured employees, those injured employees that are subject to the contract shall be provided medicines and medical supplies in the manner prescribed in the contract for as long as medicines or medical supplies are reasonably required to cure or relieve the injured employee from the effects of the injury.  Medicines provided pursuant to the contract shall be subject to the drug formulary adopted by the administrative director pursuant to Section 5307.27, and such contracts may not limit the availability of medications otherwise prescribed pursuant to the formulary based on whether the pharmacy services are provided within or outside a medical provider network.

(b) Nothing in this section shall affect the ability of employee-selected physicians to continue to prescribe and have the employer provide medicines subject to the drug formulary and medical supplies that the physicians deem reasonably required to cure or relieve the injured employee from the effects of the injury.

(c) Each contract described in subdivision (a) shall comply with standards adopted by the administrative director.  In adopting those standards, the administrative director shall seek to reduce pharmaceutical costs and may consult any relevant studies or practices in other states.  The standards shall provide for access to a pharmacy within a reasonable geographic distance from an injured employee's residence.