N.Y. Comp. Codes R. & Regs. tit. 10 § 80.65
A prescription, in order to be effective in legalizing the possession of controlled substances, shall be issued for legitimate medical purposes only. The responsibility for the proper prescribing and dispensing of controlled substances shall be on the physician, dentist, podiatrist, veterinarian or other authorized practitioner, but a corresponding liability shall rest with the pharmacist who fills the prescription. An order purporting to be a prescription, issued to an addict or habitual user of controlled substances, not in the course of professional treatment but for the purpose of providing the user with narcotics or other controlled substances sufficient to keep him comfortable by maintaining his customary use, is not a prescription within the meaning of subdivision 30 of section 3302 of the Public Health Law and the person knowingly filling such an order, as well as the person issuing it, shall be subject to the penalties provided for violation of the provisions of law relating to controlled substances.
N.Y. Comp. Codes R. & Regs. Tit. 10 § 80.65