Wash. Rev. Code § 41.05.533
(1) A health benefit plan offered to public employees and their covered dependents under this chapter that is not subject to chapter 48.43 RCW, that is issued or renewed after December 31, 2015, and that provides coverage for prescription drugs must implement a medication synchronization policy for the dispensing of prescription drugs to the plan's enrollees.
(a) If an enrollee requests medication synchronization for a new prescription, the health [benefit] plan must permit filling the drug:
(c) The health benefit plan shall adjust the enrollee cost-sharing for a prescription drug with a copayment that is dispensed for less than the standard refill amount for the purpose of synchronizing the medications by:
(2) Upon request of an enrollee, the prescribing provider or pharmacist shall:
(3) For purposes of this section, the following terms have the following meanings unless the context clearly requires otherwise:
[ 2015 c 213 s 2.]