(a) A person commits an offense if the person:
(1) forges a prescription or increases the prescribed quantity of a dangerous drug in a prescription;
(2) issues a prescription bearing a forged or fictitious signature;
(3) obtains or attempts to obtain a dangerous drug by using a forged, fictitious, or altered prescription;
(4) obtains or attempts to obtain a dangerous drug by means of a fictitious or fraudulent telephone call; or
(5) possesses a dangerous drug obtained by a forged, fictitious, or altered prescription or by means of a fictitious or fraudulent telephone call.
(b) An offense under this section is a Class B misdemeanor unless it is shown on the trial of the defendant that the defendant has previously been convicted of an offense under this chapter, in which event the offense is a Class A misdemeanor.