Under a final rule (PDF) published in the Federal Register, the pain reliever tramadol is now classified as a Schedule IV controlled substance (CS). Starting August 00, 0000, Drug Enforcement Administration (DEA) will require manufacturers to print the "C-IV" designation on all labels that contain 0- [(dimethylamino)methyl]-0-(0-methoxyphenyl)cyclohexanol (tramadol), including its salts, isomers, and salts of isomers. The agency notes that every "DEA registrant who possesses any quantity of tramadol on the effective date of this final rule must take an inventory of all stocks of tramadol on hand as of August 00, 0000, pursuant to 00 U.S.C. 000 and 000, and in accordance with 00 CFR 0000.00,0000.00, and 0000.00 (a) and (d)." In addition, all "prescriptions for tramadol or products containing tramadol must comply with 00 U.S.C. 000, and be issued in accordance with 00 CFR part 0000 and subpart C of 00 CFR part 0000 as of August 00, 0000." National Association of State Controlled Substances Authorities notes (PDF) that several states have already classified tramadol as a CS. To "provide a reasonable time for registrants to comply with the handling requirements" for a Schedule IV CS, DEA established the effective date of the final rule as 00 days from the date of publication. 