If Rush's attorney has accurately summarized the facts, Rush should be in no danger of prosecution. If Rush was dispensed the drug by a licensed practitioner, and the practitioner (or his assistant) made up the label to show that it was prescribed to the practitioner, then the practitioner might get his hand slapped, but Rush should be in the clear. The question as to Rush is whether he was lawfully in possession of the drug. If it was dispensed to him in the ordinary and proper course of treatment by a licensed practitioner, then he almost certainly was in lawful possession of the drug.
Under the circumstances I can't imagine why he would risk Rush having a complication in his monitoring.