(d) A practitioner may prescribe, administer, or dispense a controlled substance or other drug or device only (i) in good faith in the course of his professional practice, (ii) within the scope of the patient relationship, and (iii) in accordance with treatment principles accepted by a responsible segment of the medical profession. A practitioner may cause a controlled substance, other drug or device or drug to be administered by a professional assistant under his direction and supervision. see full law