Surplus, outdated, or damaged drug samples shall be disposed of as follows:

(1) Returned to the manufacturer; or

(2) Witnessed destruction by such means as to assure that the drug cannot be retrieved. However, controlled substances shall be returned to the manufacturer or disposed of in accordance with rules adopted by the commission: PROVIDED, That the commission shall adopt by rule the regulations of the federal drug enforcement administration or its lawful successor unless, stating reasonable grounds, it adopts rules consistent with such regulations.