In this section, “opioid antagonist” means: naloxone hydrochloride; or any other similarly acting and equally safe drug approved by the federal Food and Drug Administration for the treatment of a drug overdose. This section applies to: insurers and nonprofit health service plans that provide coverage for prescription drugs under individual, group, or blanket health insurance policies or contracts that are issued or delivered in the State; and health maintenance organizations that provide coverage for prescription drugs under individual or group contracts that are issued or delivered in the State. An insurer, a nonprofit health service plan, or a health maintenance organization that provides coverage for prescription drugs through a pharmacy benefits manager is subject to the requirements of this section. An entity subject to this section that includes on its formulary an opioid antagonist may apply a prior authorization requirement for an opioid antagonist only if the entity provides coverage for at least one formulation of the opioid antagonist without a prior authorization requirement.