"(2) A person who has been convicted of an offense under the act of April 14, 1972 (P.L. 233, No. 64), known as The Controlled Substance, Drug, Device and Cosmetic Act, or any equivalent Federal statute or equivalent statute of any other state, that may be punishable by a term of imprisonment exceeding two years."

There's your prohibitor, right there. At least that's the opinion I'd stand by. (No IANAL.)