(a) A physician licensed under this subtitle may supply a patient with any drug, remedy, or clinical supply necessary to meet the patient’s immediate needs.
(b) This section does not permit a physician to operate a retail pharmacy without complying with Chapter 558.

(c) This chapter does not prohibit a physician from supplying to a patient, free of charge, a drug provided to the physician by a drug manufacturer for an indigent pharmaceutical program if, in the physician’s opinion, it is advantageous to the patient, in adhering to a course of treatment prescribed by the physician, to receive the drug.