Tenn. Code Ann. § 63-10-106

No agreement between a program administrator and a pharmacy shall establish reimbursement rates or procedures that result in reimbursement rates for services rendered to persons covered by the plan that are less than the usual and customary rate charged by that vendor and paid by ordinary consumers for the same or similar services. This section does not apply to any agreements involving a pharmacy that is a member of an organized pharmacy network, such as a preferred provider organization (PPO) or a professional service administration organization (PSAO).