58 Pa. Code § 188.1
No driver, trainer, groom or official may use a controlled substance as defined in The Controlled Substance, Drug, Device and Cosmetic Act (35 P. S. §§ 780-101-780-144) or a prescription drug unless the substance was obtained directly or under a valid prescription or order from a licensed physician while acting in the course of professional practice. The driver, trainer, groom or official is responsible for giving notice to the presiding judge on a form provided by the Commission that he is using a controlled substance or prescription drug under a valid prescription or order from a licensed physician. No driver, trainer, groom or official using a controlled substance or prescription drug under a valid prescription or order will be permitted to participate in racing activities unless the physician has certified that use of the controlled substance or prescription drug will not adversely affect the driver's or official's ability to properly and safely carry out his responsibilities.
58 Pa. Code § 188.1
This section cited in 58 Pa. Code § 188.3 (relating to testing).