(a) It is unprofessional conduct for a licensed veterinarian to prescribe, administer, dispense, deliver, or order delivered any prescription drug without first having established a veterinarian-client-patient relationship and determined that such prescription drug is therapeutically indicated for the health and/or well-being of the animal(s). Prescription drugs include all controlled substances in Schedules I - V and legend drugs which bear the federal legends, recognized as such by any law of the State of Texas or of the United States.(b) It shall be unprofessional conduct and a violation of the rules of professional conduct for a licensed veterinarian to prescribe, provide, obtain, order, administer, possess, dispense, give, or deliver to or for any person prescription drugs that are not necessary or required for the medical care of animals, or where the use or possession of such drugs would promote addiction thereto. Prescription drugs are defined in subsection (a) of this section.(c) A licensed veterinarian prescribing, administering, dispensing, delivering, or ordering delivered any prescription drug must comply with the laws, including all rules, of both the United States and the State of Texas, including but not limited to Chapter 483 of the Texas Health and Safety Code.