Medicines containing hydrocodone, a highly addictive painkiller, will be subject to more restrictions under new rules published by the U.S. Drug Enforcement Administration (DEA) this week.

The DEA announced on Thursday that it is moving hydrocodone combination products (HCPs) from Schedule III to the more-restrictive Schedule II. Hydrocodone by itself is already a Schedule II drug. HCPs are drugs that contain both hydrocodone and specified amounts of other substances, such as acetaminophen or aspirin.

As a result of the new rules, which take effect in 45 days, drugs like Vicodin, Lortab, Norco and other generic versions will be subject to the same prescribing rules as codeine and other strong painkillers.

The maximum amount that can be prescribed is one 90-day supply of medication. After that, patients will have to see a health care professional if they require more. In some states, prescribing authority will be limited to physicians, not nurses or physician assistants, the Associated Press reported.

In addition, pharmacies will be required to follow stricter procedures on handling and storage of the drugs.

Hydrocodone products are among the most widely prescribed drugs in the United States. They are far less common elsewhere: Americans consume 99% of the hydrocodone produced worldwide, according to figures from the International Narcotics Control Board.

Last year the U.S. Food and Drug Administration (FDA) changed its position on the reclassification of hydrocodone. Previously, it was opposed to the move on the grounds that it would place a burden on health care providers and patients and lead to increased costs.

The reclassification was recommended by the assistant secretary for health of the U.S. Department of Health and Human Services and is supported by the DEA's own evaluation of relevant data.

"Today's action recognizes that these products are some of the most addictive and potentially dangerous prescription medications available," commented DEA Administrator Michele Leonhart.