This section applies only to a pharmacy benefits manager that provides pharmacy benefits management services on behalf of a carrier. A pharmacy benefits manager may not prohibit a pharmacy or pharmacist from: providing a beneficiary with information regarding the retail price for a prescription drug or the amount of the cost share for which the beneficiary is responsible for a prescription drug; discussing with a beneficiary information regarding the retail price for a prescription drug or the amount of the cost share for which the beneficiary is responsible for a prescription drug; or if a more affordable drug is available than one on the purchaser’s formulary and the requirements for a therapeutic interchange under §§ 15–1633.1 through 15–1639 of this subtitle are met, selling the more affordable alternative to the beneficiary. This section may not be construed to alter the requirements for a therapeutic interchange under §§ 15–1633.1 through 15–1639 of this subtitle.